bcoder

使用layout_weight时需要设置layout_width或者layout_height=0dp

分类：Android, Java 阅读 (1,411) No Responses »

4月 122017

如下图，第二行的ImageView和TextView的layout_width属性都为wrap_content，layout_weight都为１，所以两者显示的权重并不是１：１

第四行ImageView和TextView的layout_width属性都为0dp，layout_weight都为１，所以两者显示的权重是１：１

笔者猜测应该是layout_content的值被优先计算，然后再计算layout_weight的值，所以造成第二行的问题

xml部局如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp"
    tools:context=".activities.LayoutWeightTestActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@color/aquamarine"
            android:text="@string/str_helloworld" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@color/burlywood"
            android:text="@string/str_helloworld" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:adjustViewBounds="false"
            app:srcCompat="@drawable/ic_launcher_background" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@color/coral"
            android:text="@string/str_helloworld" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            app:srcCompat="@drawable/luantailang" />

        <ImageView
            android:id="@+id/imageView3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            app:srcCompat="@drawable/luantailang" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/imageView4"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            app:srcCompat="@drawable/ic_launcher_background" />

        <TextView
            android:id="@+id/textView4"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@color/deepskyblue"
            android:text="TextView" />
    </LinearLayout>

</LinearLayout>

100

101

102

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:padding="10dp"

tools:context=".activities.LayoutWeightTestActivity">

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="10dp"

android:orientation="horizontal">

<TextView

android:id="@+id/textView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:background="@color/aquamarine"

android:text="@string/str_helloworld" />

<TextView

android:id="@+id/textView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:background="@color/burlywood"

android:text="@string/str_helloworld" />

</LinearLayout>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="10dp"

android:orientation="horizontal">

<ImageView

android:id="@+id/imageView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:adjustViewBounds="false"

app:srcCompat="@drawable/ic_launcher_background" />

<TextView

android:id="@+id/textView3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:background="@color/coral"

android:text="@string/str_helloworld" />

</LinearLayout>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="10dp"

android:orientation="horizontal">

<ImageView

android:id="@+id/imageView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

app:srcCompat="@drawable/luantailang" />

<ImageView

android:id="@+id/imageView3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

app:srcCompat="@drawable/luantailang" />

</LinearLayout>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="10dp"

android:orientation="horizontal">

<ImageView

android:id="@+id/imageView4"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

app:srcCompat="@drawable/ic_launcher_background" />

<TextView

android:id="@+id/textView4"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:background="@color/deepskyblue"

android:text="TextView" />

</LinearLayout>

TextView的marquee异常一例

分类：Android, Java 阅读 (1,125) No Responses »

4月 122017

部局的xml如下：

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:baselineAligned="false">

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="3"
            android:orientation="vertical"
            android:padding="10dp">

            <TextView
                android:id="@+id/tvSongName"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginBottom="10dp"
                android:ellipsize="marquee"
                android:focusable="auto"
                android:focusableInTouchMode="true"
                android:text="光辉岁月"
                android:textSize="18sp"
                android:textStyle="bold" />

            <TextView
                android:id="@+id/tvSinger"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="5dp"
                android:layout_weight="1"
                android:ellipsize="end"
                android:text="演唱：Beyond" />

            <TextView
                android:id="@+id/tvAlbum"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="5dp"
                android:layout_weight="1"
                android:ellipsize="end"
                android:text="专辑：光辉岁月" />

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/tvPlayPosition"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginRight="5dp"
                    android:text="00:00" />

                <ProgressBar
                    android:id="@+id/progressBar2"
                    style="?android:attr/progressBarStyleHorizontal"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1" />

                <TextView
                    android:id="@+id/tvDuration"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="5dp"
                    android:text="00:00" />
            </LinearLayout>

        </LinearLayout>

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:orientation="horizontal">

            <ImageView
                android:id="@+id/imgCover"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:adjustViewBounds="true"
                android:minWidth="150dp"
                android:minHeight="150dp"
                android:scaleType="centerInside"
                android:src="@drawable/default_cover" />
        </LinearLayout>
    </LinearLayout>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:baselineAligned="false">

<LinearLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="3"

android:orientation="vertical"

android:padding="10dp">

<TextView

android:id="@+id/tvSongName"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginBottom="10dp"

android:ellipsize="marquee"

android:focusable="auto"

android:focusableInTouchMode="true"

android:text="光辉岁月"

android:textSize="18sp"

android:textStyle="bold" />

<TextView

android:id="@+id/tvSinger"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="5dp"

android:layout_weight="1"

android:ellipsize="end"

android:text="演唱：Beyond" />

<TextView

android:id="@+id/tvAlbum"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="5dp"

android:layout_weight="1"

android:ellipsize="end"

android:text="专辑：光辉岁月" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_weight="1"

android:gravity="center_vertical"

android:orientation="horizontal">

<TextView

android:id="@+id/tvPlayPosition"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginRight="5dp"

android:text="00:00" />

<ProgressBar

android:id="@+id/progressBar2"

style="?android:attr/progressBarStyleHorizontal"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1" />

<TextView

android:id="@+id/tvDuration"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="5dp"

android:text="00:00" />

</LinearLayout>

<LinearLayout

android:layout_width="0dp"

android:layout_height="match_parent"

android:layout_weight="2"

android:orientation="horizontal">

<ImageView

android:id="@+id/imgCover"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:adjustViewBounds="true"

android:minWidth="150dp"

android:minHeight="150dp"

android:scaleType="centerInside"

android:src="@drawable/default_cover" />

</LinearLayout>

部局的预览图如下

音乐标题（光辉岁月）的ellipsize属性为marquee，当设置专辑下面的当前播放进度的文本时音乐标题的marquee总是重新播放，应该是进度TextView的文本改变影响了父级的LinearLayout（按道理来说不应该影响的）。

解决办法：为父级的LinearLayout增加android:baselineAligned=”false”属性

Ubuntu16.04中编译Android6.0源码及注意事项

分类：Android, Java 阅读 (2,555) No Responses »

4月 082017

一、下载Android6.0源码

大家可以从清华的镜像站下载源码库，具体参数https://mirrors.tuna.tsinghua.edu.cn/help/AOSP/和网络上的教程

二、安装编译时需要的软件

直接连接Ubuntu速度比较慢，而且Ubuntu官方没有openjdk7的安装包了，所以更换更新源到国内的源，我把阿里和163的源都放进去了

1.先备份更新源

cp /etc/apt/sources.list /etc/apt/sources.list.20170405

1	cp /etc/apt/sources.list /etc/apt/sources.list.20170405

2. 增加阿里的源

deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu xenial partner
deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse

deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial universe

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe

deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse

deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties

deb http://archive.canonical.com/ubuntu xenial partner

deb-src http://archive.canonical.com/ubuntu xenial partner

deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe

deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse

3. 增加163的更新源

deb http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse

deb http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse

deb-src http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse

4. 执行一行apt-get update

sudo apt-get update

1	sudo apt-get update

5. 安装编译时需要的软件

sudo apt-get install openjdk-7-jdk
sudo apt-get install curl g++-multilib gcc-multilib lib32ncurses5-dev lib32readline-gplv2-dev lib32z1-dev libxml2-utils

1 2	sudo apt-get install openjdk-7-jdk sudo apt-get install curl g++-multilib gcc-multilib lib32ncurses5-dev lib32readline-gplv2-dev lib32z1-dev libxml2-utils

三、开始编译

四、常见错误及解决办法

1.编译时出现unsupported reloc 43，解决方法如下：

It works to me:
in file /art/build/Android.common_build.mk, find out:

# Host.
ART_HOST_CLANG := false
ifneq ($(WITHOUT_HOST_CLANG),true)
  # By default, host builds use clang for better warnings.
  ART_HOST_CLANG := true
endif

# Host.

ART_HOST_CLANG := false

ifneq ($(WITHOUT_HOST_CLANG),true)

# By default, host builds use clang for better warnings.

ART_HOST_CLANG := true

endif

change to :

# Host.
ART_HOST_CLANG := false
ifeq ($(WITHOUT_HOST_CLANG),false)
  # By default, host builds use clang for better warnings.
  ART_HOST_CLANG := true
endif

# Host.

ART_HOST_CLANG := false

ifeq ($(WITHOUT_HOST_CLANG),false)

# By default, host builds use clang for better warnings.

ART_HOST_CLANG := true

endif

If it still not works,try this in your android root path: cp /usr/bin/ld.gold prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.11-4.6/x86_64-linux/bin/ld

Android中文件扫描功能的实现（非递归）

分类：Uncategorized 阅读 (1,993) No Responses »

4月 032017

需要对Android中的sdcard目录进行扫描，获取文件列表，而且要对文件进行排序

本文使用了非递归的方式进行扫描，用一个栈保存需要扫描的文件夹，用while循环所有目录和文件

排序分为在内部排序和整体排序：

内部排序即每扫描到一个文件夹就对这个文件夹内的文件进行排序，然后再扫描他的子文件夹（某些场景会用到这种要求）
外部排序即扫描完所有的文件后再进行排序。

根据最后的测试，外部排序速度明显优于内部排序，内部排序的时间约是外部排序的1.3倍。

基于此优化使用排序，如果场景不允许可以先内部排序满足某些条件后再改为外部排序。

下面为文件扫描类的代码FileScanner.java

package bcoder.com.androidfunctiontestapplication.utils;

import android.util.Log;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Stack;

public class FileScanner {
    public static final String LOG_TAG = "FileScanner";
    public ArrayList<String> mFileList = new ArrayList<>();

    private boolean mIsRunning = true;

    public int scanFiles(String path){
        mFileList.clear();
        File file = new File(path);
        Stack<File> folderStack = new Stack<>();
        folderStack.push(file);

        long starttime = System.currentTimeMillis();

        while (!folderStack.empty()){
            if(!mIsRunning){
                break;
            }
            file = folderStack.pop();
            File[] files = file.listFiles();

            //　内部排序
            Arrays.sort(files, new Comparator<File>() {
                @Override
                public int compare(File o1, File o2) {
                    return o1.getName().toLowerCase().compareTo(o2.getName().toLowerCase());
                }
            });

            for(int i = 0; i < files.length;  i++){
                String fullfilepath = files[i].getAbsolutePath();

                if(files[i].isDirectory() && !"./".equals(files[i].getName())){
                    folderStack.push(files[i]);
                    mFileList.add(fullfilepath);
                } else {
                    mFileList.add(fullfilepath);
                }
            }
        }

        long timeuse = System.currentTimeMillis() - starttime;

        Log.d(LOG_TAG, String.format("TimeUse: %d", timeuse));

        Arrays.sort(mFileList.toArray());

        //　外部排序
        mFileList.sort(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.compareTo(o2);
            }
        });

        Log.d(LOG_TAG, String.format("File count: %d", mFileList.size()));

//        for(int i = 0; i < mFileList.size(); i++){
//            Log.d(LOG_TAG, mFileList.get(i));
//        }

        return mFileList.size();
    }

    public void stopScan(){
        mIsRunning = false;
    }
}

package bcoder.com.androidfunctiontestapplication.utils;

import android.util.Log;

import java.io.File;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Comparator;

import java.util.Stack;

public class FileScanner {

public static final String LOG_TAG = "FileScanner";

public ArrayList<String> mFileList = new ArrayList<>();

private boolean mIsRunning = true;

public int scanFiles(String path){

mFileList.clear();

File file = new File(path);

Stack<File> folderStack = new Stack<>();

folderStack.push(file);

long starttime = System.currentTimeMillis();

while (!folderStack.empty()){

if(!mIsRunning){

break;

}

file = folderStack.pop();

File[] files = file.listFiles();

//　内部排序

Arrays.sort(files, new Comparator<File>() {

@Override

public int compare(File o1, File o2) {

return o1.getName().toLowerCase().compareTo(o2.getName().toLowerCase());

}

});

for(int i = 0; i < files.length; i++){

String fullfilepath = files[i].getAbsolutePath();

if(files[i].isDirectory() && !"./".equals(files[i].getName())){

folderStack.push(files[i]);

mFileList.add(fullfilepath);

} else {

mFileList.add(fullfilepath);

}

long timeuse = System.currentTimeMillis() - starttime;

Log.d(LOG_TAG, String.format("TimeUse: %d", timeuse));

Arrays.sort(mFileList.toArray());

//　外部排序

mFileList.sort(new Comparator<String>() {

@Override

public int compare(String o1, String o2) {

return o1.compareTo(o2);

}

});

Log.d(LOG_TAG, String.format("File count: %d", mFileList.size()));

// for(int i = 0; i < mFileList.size(); i++){

// Log.d(LOG_TAG, mFileList.get(i));

// }

return mFileList.size();

}

public void stopScan(){

mIsRunning = false;

}

github项目地址：https://github.com/wintergoes/AndroidFunctionTestApplication

Android开发中使用jni

分类：Android, Java, Java语言阅读 (1,121) No Responses »

3月 202017

一、jni背景知识

　　jni是Java Native Interface的缩写，jni并不是Android开发的特性，而是在java的早期版本中就已经支持了，用于java层和Native层进行通讯的中间桥梁，大部分情况下使用c和c++进行编写，也可以使用其他的语言编写，只要满足约定的接口就可以。

二、Jni的副作用

　　Jni有以下副作用：

1、不再具有跨平台可移植性，如果移植到其他平台，需要开发Native层的相关代码

2、Native层的程序如果有问题将会导致java层的程序崩溃

三、开发步骤简述(Ubuntu 16 + openjdk-8-jdk)

　　1、在java代码中定义Native函数，比如java文件名为JniTest.java

public class JniTest{

	static {
		System.loadLibrary("jnitest");
	}

	native int calc(int i1, int i2);


	public static void main(String args[]){
		JniTest jnitest = new JniTest();
		int sum = jnitest.calc(322, 21);
		System.out.print(sum);
	}
}

public class JniTest{

static {

System.loadLibrary("jnitest");

}

native int calc(int i1, int i2);

public static void main(String args[]){

JniTest jnitest = new JniTest();

int sum = jnitest.calc(322, 21);

System.out.print(sum);

}

　　2、使用javac编译java文件，javac JniTest.java

　　3、使用javah工具传入java类名，生成native层的头文件，javah JniTest，此时目录下会有一个JniTest.h

　　4、新建一个JniTest.cc的文件，并添加如下内容：

#include "JniTest.h"

JNIEXPORT jint JNICALL Java_JniTest_calc
  (JNIEnv *env, jobject obj, jint i1, jint i2){
	return i1 + i2;
};

#include "JniTest.h"

JNIEXPORT jint JNICALL Java_JniTest_calc

(JNIEnv *env, jobject obj, jint i1, jint i2){

return i1 + i2;

};

　　5、将navtive层的代码编译成so库，命令如下：

gcc -I/usr/lib/jvm/java-8-openjdk-amd64/include/ -I/usr/lib/jvm/java-8-openjdk-amd64/include/linux -Wall -g -fPIC -c JniTest.cc -o jnitest.o
gcc -shared jnitest.o -o libjnitest.so

1 2	gcc -I/usr/lib/jvm/java-8-openjdk-amd64/include/ -I/usr/lib/jvm/java-8-openjdk-amd64/include/linux -Wall -g -fPIC -c JniTest.cc -o jnitest.o gcc -shared jnitest.o -o libjnitest.so

　　6、在java层使用System.loadLibrary(“jnitest”);加载动态库，并调用函数，见第1中的java代码

参考链接：

https://baike.baidu.com/item/JNI/9412164?fr=aladdin

mysql的一些触发器操作

分类：Database, MySQL 阅读 (1,173) No Responses »

3月 062017

1. 查看已创建的触发器
SELECT * FROM information_schema.TRIGGERS;
也可以使用
show triggers;

查询名字为my_trigger的触发器：
select * from information_schema.triggers where TRIGGER_NAME=’my_trigger’;

2. 删除已创建的触发器
drop trigger my_trigger;

ssh闲置一段时间后自动断开的解决办法

分类：Linux, Operating System 阅读 (1,367) No Responses »

3月 052017

转载自：http://blog.csdn.net/quqi99/article/details/51434248

SSH连接总是隔一段时间没有输入时就断开，解决办法如下：

方法一：修改服务端配置
sudo vi /etc/ssh/sshd_config
ClientAliveInterval 60 #服务端主动向客户端请求响应的间隔
ClientAliveCountMax 10 #服务器发出请求后客户端没有响应的次数达到一定值就自动断开
sudo restart ssh

方法二：修改客户端配置
sudo vi /etc/ssh/ssh_config #或~/.ssh/config

TCPKeepAlive=yes
ServerAliveInterval 60 #客户端主动向服务端请求响应的间隔

或

ssh -i <key-file> -o StrictHostKeyChecking=no -o TCPKeepAlive=yes -o ServerAliveInterval=30 ubuntu@<ip>

上面方式任选一种，我选客户端配置方式。

几种常用的Android补间动画

分类：Android, Java 阅读 (2,208) No Responses »

3月 012017

　　本文总结了几种常用的补间动画效果，具体的使用方法请参考网络上的其他文章：

　　先总结几点注意事项：

如果是多个动画组成的动画系统，duration值最好会设置成相同的，否则Activity切换的时候会出现黑底
overridePendingTransition有的时候需要rebuild项目才有效果

　　1.放大效果（附加淡入效果）

　　在res/anim目录下新建zoomin.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:interpolator="@android:anim/decelerate_interpolator"
     android:zAdjustment="top">
    <scale android:fromXScale="0.3" android:toXScale="1.0"
           android:fromYScale="0.3" android:toYScale="1.0"
           android:pivotX="50%p" android:pivotY="50%p"
           android:duration="300" />

    <alpha android:fromAlpha="0.1" android:toAlpha="1.0"
           android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/decelerate_interpolator"

android:zAdjustment="top">

<scale android:fromXScale="0.3" android:toXScale="1.0"

android:fromYScale="0.3" android:toYScale="1.0"

android:pivotX="50%p" android:pivotY="50%p"

android:duration="300" />

<alpha android:fromAlpha="0.1" android:toAlpha="1.0"

android:duration="300"/>

</set>

　　2.缩小效果（附加淡出效果）

　　在res/anim目录新建zoomout.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:interpolator="@android:anim/decelerate_interpolator"
     android:zAdjustment="top">
    <scale android:fromXScale="1.0" android:toXScale=".5"
           android:fromYScale="1.0" android:toYScale=".5"
           android:pivotX="50%p" android:pivotY="50%p"
           android:duration="300" />

    <alpha android:fromAlpha="1.0" android:toAlpha="0.1"
           android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/decelerate_interpolator"

android:zAdjustment="top">

<scale android:fromXScale="1.0" android:toXScale=".5"

android:fromYScale="1.0" android:toYScale=".5"

android:pivotX="50%p" android:pivotY="50%p"

android:duration="300" />

<alpha android:fromAlpha="1.0" android:toAlpha="0.1"

android:duration="300"/>

</set>

　　3. 淡入效果

　　在res/anim目录新建fadein.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <alpha
        android:fromAlpha="0.1"
        android:toAlpha="1.0"
        android:duration="300" />
</set>

<?xml version="1.0" encoding="utf-8"?>

<alpha

android:fromAlpha="0.1"

android:toAlpha="1.0"

android:duration="300" />

</set>

　　4. 淡出效果

　　在res/anim目录下新建fadeout.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <alpha
        android:fromAlpha="1.0"
        android:toAlpha="0.1"
        android:duration="300" />
</set>

<?xml version="1.0" encoding="utf-8"?>

<alpha

android:fromAlpha="1.0"

android:toAlpha="0.1"

android:duration="300" />

</set>

　　5. 纵向布幕拉开效果（自中间往上下拉开）

　　在res/anim目录下新建open_verticaly_from_middle.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:interpolator="@android:anim/decelerate_interpolator">
    <scale android:fromXScale="1.0" android:toXScale="1.0"
           android:fromYScale="0.1" android:toYScale="1.0"
           android:pivotX="50%p" android:pivotY="50%p"
           android:duration="300" />

    <alpha
        android:fromAlpha="1.0"
        android:toAlpha="1.0"
        android:duration="300" />
</set>

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/decelerate_interpolator">

<scale android:fromXScale="1.0" android:toXScale="1.0"

android:fromYScale="0.1" android:toYScale="1.0"

android:pivotX="50%p" android:pivotY="50%p"

android:duration="300" />

<alpha

android:fromAlpha="1.0"

android:toAlpha="1.0"

android:duration="300" />

</set>

　　6.纵向布幕关闭效果（自上下往中间关闭）　

　　在res/anim目录下新建close_verticaly_to_middle.xml，并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:interpolator="@android:anim/decelerate_interpolator">
    <scale android:fromXScale="1.0" android:toXScale="1.0"
           android:fromYScale="1.0" android:toYScale="0.1"
           android:pivotX="50%p" android:pivotY="50%p"
           android:duration="300" />

    <alpha
        android:fromAlpha="1.0"
        android:toAlpha="1.0"
        android:duration="300" />
</set>

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/decelerate_interpolator">

<scale android:fromXScale="1.0" android:toXScale="1.0"

android:fromYScale="1.0" android:toYScale="0.1"

android:pivotX="50%p" android:pivotY="50%p"

android:duration="300" />

<alpha

android:fromAlpha="1.0"

android:toAlpha="1.0"

android:duration="300" />

</set>

　　7. 从顶部进入

　　在res/anim中建立文件slide_in_from_top.xml, 并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromYDelta="-100%"
               android:toYDelta="0"
               android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<translate android:fromYDelta="-100%"

android:toYDelta="0"

android:duration="300"/>

</set>

　　8. 从底部进入

　　在res/anim中新建文件slide_in_from_bottom.xml, 并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="0"
               android:fromYDelta="200%"
               android:toYDelta="0"
               android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<translate android:fromXDelta="0"

android:fromYDelta="200%"

android:toYDelta="0"

android:duration="300"/>

</set>

　　9. 从顶部划出

　　在res/anim中新建文件slide_out_to_top.xml, 并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromYDelta="0"
               android:toYDelta="-100%"
               android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<translate android:fromYDelta="0"

android:toYDelta="-100%"

android:duration="300"/>

</set>

　　10. 从底部划出

　　在res/anim中新建文件slide_out_to_bottom.xml, 并粘贴下面的代码

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromYDelta="0"
               android:toYDelta="200%"
               android:duration="300"/>
</set>

<?xml version="1.0" encoding="utf-8"?>

<translate android:fromYDelta="0"

android:toYDelta="200%"

android:duration="300"/>

</set>

startActivity流程分析

分类：Android, Java 阅读 (1,161) No Responses »

2月 212017

首先调用Activity.java中的startActivity

    public void startActivity(Intent intent) {
        this.startActivity(intent, null);
    }

public void startActivity(Intent intent) {

this.startActivity(intent, null);

}

调用了另外一startActivity函数，增加了options参数，为避免过于复杂，我们使用options为null

    public void startActivity(Intent intent, @Nullable Bundle options) {
        if (options != null) {
            startActivityForResult(intent, -1, options);
        } else {
            // Note we want to go through this call for compatibility with
            // applications that may have overridden the method.
            startActivityForResult(intent, -1);
        }
    }

public void startActivity(Intent intent, @Nullable Bundle options) {

if (options != null) {

startActivityForResult(intent, -1, options);

} else {

// Note we want to go through this call for compatibility with

// applications that may have overridden the method.

startActivityForResult(intent, -1);

}

实际上又调用到了startActivityForResult函数

    public void startActivityForResult(@RequiresPermission Intent intent, int requestCode) {
        startActivityForResult(intent, requestCode, null);
    }

public void startActivityForResult(@RequiresPermission Intent intent, int requestCode) {

startActivityForResult(intent, requestCode, null);

}

同样，带options参数的startActivityForResult

    public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,
            @Nullable Bundle options) {
        if (mParent == null) {
            options = transferSpringboardActivityOptions(options);
            Instrumentation.ActivityResult ar =
                mInstrumentation.execStartActivity(
                    this, mMainThread.getApplicationThread(), mToken, this,
                    intent, requestCode, options);
            if (ar != null) {
                mMainThread.sendActivityResult(
                    mToken, mEmbeddedID, requestCode, ar.getResultCode(),
                    ar.getResultData());
            }
            if (requestCode >= 0) {
                // If this start is requesting a result, we can avoid making
                // the activity visible until the result is received.  Setting
                // this code during onCreate(Bundle savedInstanceState) or onResume() will keep the
                // activity hidden during this time, to avoid flickering.
                // This can only be done when a result is requested because
                // that guarantees we will get information back when the
                // activity is finished, no matter what happens to it.
                mStartedActivity = true;
            }

            cancelInputsAndStartExitTransition(options);
            // TODO Consider clearing/flushing other event sources and events for child windows.
        } else {
            if (options != null) {
                mParent.startActivityFromChild(this, intent, requestCode, options);
            } else {
                // Note we want to go through this method for compatibility with
                // existing applications that may have overridden it.
                mParent.startActivityFromChild(this, intent, requestCode);
            }
        }
    }

public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,

@Nullable Bundle options) {

if (mParent == null) {

options = transferSpringboardActivityOptions(options);

Instrumentation.ActivityResult ar =

mInstrumentation.execStartActivity(

this, mMainThread.getApplicationThread(), mToken, this,

intent, requestCode, options);

if (ar != null) {

mMainThread.sendActivityResult(

mToken, mEmbeddedID, requestCode, ar.getResultCode(),

ar.getResultData());

}

if (requestCode >= 0) {

// If this start is requesting a result, we can avoid making

// the activity visible until the result is received. Setting

// this code during onCreate(Bundle savedInstanceState) or onResume() will keep the

// activity hidden during this time, to avoid flickering.

// This can only be done when a result is requested because

// that guarantees we will get information back when the

// activity is finished, no matter what happens to it.

mStartedActivity = true;

}

cancelInputsAndStartExitTransition(options);

// TODO Consider clearing/flushing other event sources and events for child windows.

} else {

if (options != null) {

mParent.startActivityFromChild(this, intent, requestCode, options);

} else {

// Note we want to go through this method for compatibility with

// existing applications that may have overridden it.

mParent.startActivityFromChild(this, intent, requestCode);

}

我们这里假设mParent为null

然后调用Instrumentation的executeStartActivity

    public ActivityResult execStartActivity(
            Context who, IBinder contextThread, IBinder token, Activity target,
            Intent intent, int requestCode, Bundle options) {
        IApplicationThread whoThread = (IApplicationThread) contextThread;
        if (mActivityMonitors != null) {
            synchronized (mSync) {
                final int N = mActivityMonitors.size();
                for (int i=0; i<N; i++) {
                    final ActivityMonitor am = mActivityMonitors.get(i);
                    if (am.match(who, null, intent)) {
                        am.mHits++;
                        if (am.isBlocking()) {
                            return requestCode >= 0 ? am.getResult() : null;
                        }
                        break;
                    }
                }
            }
        }
        try {
            intent.migrateExtraStreamToClipData();
            intent.prepareToLeaveProcess();
            int result = ActivityManagerNative.getDefault()
                .startActivity(whoThread, who.getBasePackageName(), intent,
                        intent.resolveTypeIfNeeded(who.getContentResolver()),
                        token, target != null ? target.mEmbeddedID : null,
                        requestCode, 0, null, null, options);
            checkStartActivityResult(result, intent);
        } catch (RemoteException e) {
        }
        return null;
    }

public ActivityResult execStartActivity(

Context who, IBinder contextThread, IBinder token, Activity target,

Intent intent, int requestCode, Bundle options) {

IApplicationThread whoThread = (IApplicationThread) contextThread;

if (mActivityMonitors != null) {

synchronized (mSync) {

final int N = mActivityMonitors.size();

for (int i=0; i<N; i++) {

final ActivityMonitor am = mActivityMonitors.get(i);

if (am.match(who, null, intent)) {

am.mHits++;

if (am.isBlocking()) {

return requestCode >= 0 ? am.getResult() : null;

}

break;

}

try {

intent.migrateExtraStreamToClipData();

intent.prepareToLeaveProcess();

int result = ActivityManagerNative.getDefault()

.startActivity(whoThread, who.getBasePackageName(), intent,

intent.resolveTypeIfNeeded(who.getContentResolver()),

token, target != null ? target.mEmbeddedID : null,

requestCode, 0, null, null, options);

checkStartActivityResult(result, intent);

} catch (RemoteException e) {

}

return null;

}

然后调用ActivityManagerService里的startActivity和startActivityAsUser

    @Override
    public final int startActivity(IApplicationThread caller, String callingPackage,
            Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags,
            String profileFile, ParcelFileDescriptor profileFd, Bundle options) {
        return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,
                resultWho, requestCode,
                startFlags, profileFile, profileFd, options, UserHandle.getCallingUserId());
    }

    @Override
    public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
            Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags,
            String profileFile, ParcelFileDescriptor profileFd, Bundle options, int userId) {
        enforceNotIsolatedCaller("startActivity");
        userId = handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), userId,
                false, true, "startActivity", null);
        // TODO: Switch to user app stacks here.
        return mStackSupervisor.startActivityMayWait(caller, -1, callingPackage, intent, resolvedType,
                resultTo, resultWho, requestCode, startFlags, profileFile, profileFd,
                null, null, options, userId);
    }

@Override

public final int startActivity(IApplicationThread caller, String callingPackage,

Intent intent, String resolvedType, IBinder resultTo,

String resultWho, int requestCode, int startFlags,

String profileFile, ParcelFileDescriptor profileFd, Bundle options) {

return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,

resultWho, requestCode,

startFlags, profileFile, profileFd, options, UserHandle.getCallingUserId());

}

@Override

public final int startActivityAsUser(IApplicationThread caller, String callingPackage,

Intent intent, String resolvedType, IBinder resultTo,

String resultWho, int requestCode, int startFlags,

String profileFile, ParcelFileDescriptor profileFd, Bundle options, int userId) {

enforceNotIsolatedCaller("startActivity");

userId = handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), userId,

false, true, "startActivity", null);

// TODO: Switch to user app stacks here.

return mStackSupervisor.startActivityMayWait(caller, -1, callingPackage, intent, resolvedType,

resultTo, resultWho, requestCode, startFlags, profileFile, profileFd,

null, null, options, userId);

}

mStackSupervisor.startActivityMayWait函数

    final int startActivityMayWait(IApplicationThread caller, int callingUid,
            String callingPackage, Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags, String profileFile,
            ParcelFileDescriptor profileFd, WaitResult outResult, Configuration config,
            Bundle options, int userId) {
        Slog.i(TAG, "startActivityMayWait, liuderu"); 
        // Refuse possible leaked file descriptors
        if (intent != null && intent.hasFileDescriptors()) {
            throw new IllegalArgumentException("File descriptors passed in Intent");
        }
        boolean componentSpecified = intent.getComponent() != null;

        // Don't modify the client's object!
        intent = new Intent(intent);

        // Collect information about the target of the Intent.
        ActivityInfo aInfo = resolveActivity(intent, resolvedType, startFlags,
                profileFile, profileFd, userId);

        synchronized (mService) {
            int callingPid;
            if (callingUid >= 0) {
                callingPid = -1;
            } else if (caller == null) {
                callingPid = Binder.getCallingPid();
                callingUid = Binder.getCallingUid();
            } else {
                callingPid = callingUid = -1;
            }

            final ActivityStack stack = getFocusedStack();
            stack.mConfigWillChange = config != null
                    && mService.mConfiguration.diff(config) != 0;
            if (DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Starting activity when config will change = " + stack.mConfigWillChange);

            final long origId = Binder.clearCallingIdentity();

            if (aInfo != null &&
                    (aInfo.applicationInfo.flags&ApplicationInfo.FLAG_CANT_SAVE_STATE) != 0) {
                // This may be a heavy-weight process!  Check to see if we already
                // have another, different heavy-weight process running.
                if (aInfo.processName.equals(aInfo.applicationInfo.packageName)) {
                    if (mService.mHeavyWeightProcess != null &&
                            (mService.mHeavyWeightProcess.info.uid != aInfo.applicationInfo.uid ||
                            !mService.mHeavyWeightProcess.processName.equals(aInfo.processName))) {
                        int realCallingUid = callingUid;
                        if (caller != null) {
                            ProcessRecord callerApp = mService.getRecordForAppLocked(caller);
                            if (callerApp != null) {
                                realCallingUid = callerApp.info.uid;
                            } else {
                                Slog.w(TAG, "Unable to find app for caller " + caller
                                      + " (pid=" + callingPid + ") when starting: "
                                      + intent.toString());
                                ActivityOptions.abort(options);
                                return ActivityManager.START_PERMISSION_DENIED;
                            }
                        }

                        IIntentSender target = mService.getIntentSenderLocked(
                                ActivityManager.INTENT_SENDER_ACTIVITY, "android",
                                realCallingUid, userId, null, null, 0, new Intent[] { intent },
                                new String[] { resolvedType }, PendingIntent.FLAG_CANCEL_CURRENT
                                | PendingIntent.FLAG_ONE_SHOT, null);

                        Intent newIntent = new Intent();
                        if (requestCode >= 0) {
                            // Caller is requesting a result.
                            newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_HAS_RESULT, true);
                        }
                        newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_INTENT,
                                new IntentSender(target));
                        if (mService.mHeavyWeightProcess.activities.size() > 0) {
                            ActivityRecord hist = mService.mHeavyWeightProcess.activities.get(0);
                            newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_CUR_APP,
                                    hist.packageName);
                            newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_CUR_TASK,
                                    hist.task.taskId);
                        }
                        newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_NEW_APP,
                                aInfo.packageName);
                        newIntent.setFlags(intent.getFlags());
                        newIntent.setClassName("android",
                                HeavyWeightSwitcherActivity.class.getName());
                        intent = newIntent;
                        resolvedType = null;
                        caller = null;
                        callingUid = Binder.getCallingUid();
                        callingPid = Binder.getCallingPid();
                        componentSpecified = true;
                        try {
                            ResolveInfo rInfo =
                                AppGlobals.getPackageManager().resolveIntent(
                                        intent, null,
                                        PackageManager.MATCH_DEFAULT_ONLY
                                        | ActivityManagerService.STOCK_PM_FLAGS, userId);
                            aInfo = rInfo != null ? rInfo.activityInfo : null;
                            aInfo = mService.getActivityInfoForUser(aInfo, userId);
                        } catch (RemoteException e) {
                            aInfo = null;
                        }
                    }
                }
            }

            int res = startActivityLocked(caller, intent, resolvedType,
                    aInfo, resultTo, resultWho, requestCode, callingPid, callingUid,
                    callingPackage, startFlags, options, componentSpecified, null);

            if (stack.mConfigWillChange) {
                // If the caller also wants to switch to a new configuration,
                // do so now.  This allows a clean switch, as we are waiting
                // for the current activity to pause (so we will not destroy
                // it), and have not yet started the next activity.
                mService.enforceCallingPermission(android.Manifest.permission.CHANGE_CONFIGURATION,
                        "updateConfiguration()");
                stack.mConfigWillChange = false;
                if (DEBUG_CONFIGURATION) Slog.v(TAG,
                        "Updating to new configuration after starting activity.");
                mService.updateConfigurationLocked(config, null, false, false);
            }

            Binder.restoreCallingIdentity(origId);

            if (outResult != null) {
                outResult.result = res;
                if (res == ActivityManager.START_SUCCESS) {
                    mWaitingActivityLaunched.add(outResult);
                    do {
                        try {
                            mService.wait();
                        } catch (InterruptedException e) {
                        }
                    } while (!outResult.timeout && outResult.who == null);
                } else if (res == ActivityManager.START_TASK_TO_FRONT) {
                    ActivityRecord r = stack.topRunningActivityLocked(null);
                    if (r.nowVisible) {
                        outResult.timeout = false;
                        outResult.who = new ComponentName(r.info.packageName, r.info.name);
                        outResult.totalTime = 0;
                        outResult.thisTime = 0;
                    } else {
                        outResult.thisTime = SystemClock.uptimeMillis();
                        mWaitingActivityVisible.add(outResult);
                        do {
                            try {
                                mService.wait();
                            } catch (InterruptedException e) {
                            }
                        } while (!outResult.timeout && outResult.who == null);
                    }
                }
            }

            return res;
        }
    }

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final int startActivityMayWait(IApplicationThread caller, int callingUid,

String callingPackage, Intent intent, String resolvedType, IBinder resultTo,

String resultWho, int requestCode, int startFlags, String profileFile,

ParcelFileDescriptor profileFd, WaitResult outResult, Configuration config,

Bundle options, int userId) {

Slog.i(TAG, "startActivityMayWait, liuderu");

// Refuse possible leaked file descriptors

if (intent != null && intent.hasFileDescriptors()) {

throw new IllegalArgumentException("File descriptors passed in Intent");

}

boolean componentSpecified = intent.getComponent() != null;

// Don't modify the client's object!

intent = new Intent(intent);

// Collect information about the target of the Intent.

ActivityInfo aInfo = resolveActivity(intent, resolvedType, startFlags,

profileFile, profileFd, userId);

synchronized (mService) {

int callingPid;

if (callingUid >= 0) {

callingPid = -1;

} else if (caller == null) {

callingPid = Binder.getCallingPid();

callingUid = Binder.getCallingUid();

} else {

callingPid = callingUid = -1;

}

final ActivityStack stack = getFocusedStack();

stack.mConfigWillChange = config != null

&& mService.mConfiguration.diff(config) != 0;

if (DEBUG_CONFIGURATION) Slog.v(TAG,

"Starting activity when config will change = " + stack.mConfigWillChange);

final long origId = Binder.clearCallingIdentity();

if (aInfo != null &&

(aInfo.applicationInfo.flags&ApplicationInfo.FLAG_CANT_SAVE_STATE) != 0) {

// This may be a heavy-weight process! Check to see if we already

// have another, different heavy-weight process running.

if (aInfo.processName.equals(aInfo.applicationInfo.packageName)) {

if (mService.mHeavyWeightProcess != null &&

(mService.mHeavyWeightProcess.info.uid != aInfo.applicationInfo.uid ||

!mService.mHeavyWeightProcess.processName.equals(aInfo.processName))) {

int realCallingUid = callingUid;

if (caller != null) {

ProcessRecord callerApp = mService.getRecordForAppLocked(caller);

if (callerApp != null) {

realCallingUid = callerApp.info.uid;

} else {

Slog.w(TAG, "Unable to find app for caller " + caller

+ " (pid=" + callingPid + ") when starting: "

+ intent.toString());

ActivityOptions.abort(options);

return ActivityManager.START_PERMISSION_DENIED;

}

IIntentSender target = mService.getIntentSenderLocked(

ActivityManager.INTENT_SENDER_ACTIVITY, "android",

realCallingUid, userId, null, null, 0, new Intent[] { intent },

new String[] { resolvedType }, PendingIntent.FLAG_CANCEL_CURRENT

| PendingIntent.FLAG_ONE_SHOT, null);

Intent newIntent = new Intent();

if (requestCode >= 0) {

// Caller is requesting a result.

newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_HAS_RESULT, true);

}

newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_INTENT,

new IntentSender(target));

if (mService.mHeavyWeightProcess.activities.size() > 0) {

ActivityRecord hist = mService.mHeavyWeightProcess.activities.get(0);

newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_CUR_APP,

hist.packageName);

newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_CUR_TASK,

hist.task.taskId);

}

newIntent.putExtra(HeavyWeightSwitcherActivity.KEY_NEW_APP,

aInfo.packageName);

newIntent.setFlags(intent.getFlags());

newIntent.setClassName("android",

HeavyWeightSwitcherActivity.class.getName());

intent = newIntent;

resolvedType = null;

caller = null;

callingUid = Binder.getCallingUid();

callingPid = Binder.getCallingPid();

componentSpecified = true;

try {

ResolveInfo rInfo =

AppGlobals.getPackageManager().resolveIntent(

intent, null,

PackageManager.MATCH_DEFAULT_ONLY

| ActivityManagerService.STOCK_PM_FLAGS, userId);

aInfo = rInfo != null ? rInfo.activityInfo : null;

aInfo = mService.getActivityInfoForUser(aInfo, userId);

} catch (RemoteException e) {

aInfo = null;

}

int res = startActivityLocked(caller, intent, resolvedType,

aInfo, resultTo, resultWho, requestCode, callingPid, callingUid,

callingPackage, startFlags, options, componentSpecified, null);

if (stack.mConfigWillChange) {

// If the caller also wants to switch to a new configuration,

// do so now. This allows a clean switch, as we are waiting

// for the current activity to pause (so we will not destroy

// it), and have not yet started the next activity.

mService.enforceCallingPermission(android.Manifest.permission.CHANGE_CONFIGURATION,

"updateConfiguration()");

stack.mConfigWillChange = false;

if (DEBUG_CONFIGURATION) Slog.v(TAG,

"Updating to new configuration after starting activity.");

mService.updateConfigurationLocked(config, null, false, false);

}

Binder.restoreCallingIdentity(origId);

if (outResult != null) {

outResult.result = res;

if (res == ActivityManager.START_SUCCESS) {

mWaitingActivityLaunched.add(outResult);

do {

try {

mService.wait();

} catch (InterruptedException e) {

}

} while (!outResult.timeout && outResult.who == null);

} else if (res == ActivityManager.START_TASK_TO_FRONT) {

ActivityRecord r = stack.topRunningActivityLocked(null);

if (r.nowVisible) {

outResult.timeout = false;

outResult.who = new ComponentName(r.info.packageName, r.info.name);

outResult.totalTime = 0;

outResult.thisTime = 0;

} else {

outResult.thisTime = SystemClock.uptimeMillis();

mWaitingActivityVisible.add(outResult);

do {

try {

mService.wait();

} catch (InterruptedException e) {

}

} while (!outResult.timeout && outResult.who == null);

}

return res;

}

mStackSupervisor.startActivityLocked函数

    final int startActivityLocked(IApplicationThread caller,
            Intent intent, String resolvedType, ActivityInfo aInfo, IBinder resultTo,
            String resultWho, int requestCode,
            int callingPid, int callingUid, String callingPackage, int startFlags, Bundle options,
            boolean componentSpecified, ActivityRecord[] outActivity) {
        int err = ActivityManager.START_SUCCESS;

        ProcessRecord callerApp = null;
        if (caller != null) {
            callerApp = mService.getRecordForAppLocked(caller);
            if (callerApp != null) {
                callingPid = callerApp.pid;
                callingUid = callerApp.info.uid;
            } else {
                Slog.w(TAG, "Unable to find app for caller " + caller
                      + " (pid=" + callingPid + ") when starting: "
                      + intent.toString());
                err = ActivityManager.START_PERMISSION_DENIED;
            }
        }

        if (err == ActivityManager.START_SUCCESS) {
            final int userId = aInfo != null ? UserHandle.getUserId(aInfo.applicationInfo.uid) : 0;
            Slog.i(TAG, "START u" + userId + " {" + intent.toShortString(true, true, true, false)
                    + "} from pid " + (callerApp != null ? callerApp.pid : callingPid));
        }

        ActivityRecord sourceRecord = null;
        ActivityRecord resultRecord = null;
        if (resultTo != null) {
            sourceRecord = isInAnyStackLocked(resultTo);
            if (DEBUG_RESULTS) Slog.v(
                TAG, "Will send result to " + resultTo + " " + sourceRecord);
            if (sourceRecord != null) {
                if (requestCode >= 0 && !sourceRecord.finishing) {
                    resultRecord = sourceRecord;
                }
            }
        }
        ActivityStack resultStack = resultRecord == null ? null : resultRecord.task.stack;

        int launchFlags = intent.getFlags();

        if ((launchFlags&Intent.FLAG_ACTIVITY_FORWARD_RESULT) != 0
                && sourceRecord != null) {
            // Transfer the result target from the source activity to the new
            // one being started, including any failures.
            if (requestCode >= 0) {
                ActivityOptions.abort(options);
                return ActivityManager.START_FORWARD_AND_REQUEST_CONFLICT;
            }
            resultRecord = sourceRecord.resultTo;
            resultWho = sourceRecord.resultWho;
            requestCode = sourceRecord.requestCode;
            sourceRecord.resultTo = null;
            if (resultRecord != null) {
                resultRecord.removeResultsLocked(
                    sourceRecord, resultWho, requestCode);
            }
            if (sourceRecord.launchedFromUid == callingUid) {
                // The new activity is being launched from the same uid as the previous
                // activity in the flow, and asking to forward its result back to the
                // previous.  In this case the activity is serving as a trampoline between
                // the two, so we also want to update its launchedFromPackage to be the
                // same as the previous activity.  Note that this is safe, since we know
                // these two packages come from the same uid; the caller could just as
                // well have supplied that same package name itself.  This specifially
                // deals with the case of an intent picker/chooser being launched in the app
                // flow to redirect to an activity picked by the user, where we want the final
                // activity to consider it to have been launched by the previous app activity.
                callingPackage = sourceRecord.launchedFromPackage;
            }
        }

        if (err == ActivityManager.START_SUCCESS && intent.getComponent() == null) {
            // We couldn't find a class that can handle the given Intent.
            // That's the end of that!
            err = ActivityManager.START_INTENT_NOT_RESOLVED;
        }

        if (err == ActivityManager.START_SUCCESS && aInfo == null) {
            // We couldn't find the specific class specified in the Intent.
            // Also the end of the line.
            err = ActivityManager.START_CLASS_NOT_FOUND;
        }

        if (err != ActivityManager.START_SUCCESS) {
            if (resultRecord != null) {
                resultStack.sendActivityResultLocked(-1,
                    resultRecord, resultWho, requestCode,
                    Activity.RESULT_CANCELED, null);
            }
            setDismissKeyguard(false);
            ActivityOptions.abort(options);
            return err;
        }

        final int startAnyPerm = mService.checkPermission(
                START_ANY_ACTIVITY, callingPid, callingUid);
        final int componentPerm = mService.checkComponentPermission(aInfo.permission, callingPid,
                callingUid, aInfo.applicationInfo.uid, aInfo.exported);
        if (startAnyPerm != PERMISSION_GRANTED && componentPerm != PERMISSION_GRANTED) {
            if (resultRecord != null) {
                resultStack.sendActivityResultLocked(-1,
                    resultRecord, resultWho, requestCode,
                    Activity.RESULT_CANCELED, null);
            }
            setDismissKeyguard(false);
            String msg;
            if (!aInfo.exported) {
                msg = "Permission Denial: starting " + intent.toString()
                        + " from " + callerApp + " (pid=" + callingPid
                        + ", uid=" + callingUid + ")"
                        + " not exported from uid " + aInfo.applicationInfo.uid;
            } else {
                msg = "Permission Denial: starting " + intent.toString()
                        + " from " + callerApp + " (pid=" + callingPid
                        + ", uid=" + callingUid + ")"
                        + " requires " + aInfo.permission;
            }
            Slog.w(TAG, msg);
            throw new SecurityException(msg);
        }

        boolean abort = !mService.mIntentFirewall.checkStartActivity(intent, callingUid,
                callingPid, resolvedType, aInfo.applicationInfo);

        if (mService.mController != null) {
            try {
                // The Intent we give to the watcher has the extra data
                // stripped off, since it can contain private information.
                Intent watchIntent = intent.cloneFilter();
                abort |= !mService.mController.activityStarting(watchIntent,
                        aInfo.applicationInfo.packageName);
            } catch (RemoteException e) {
                mService.mController = null;
            }
        }

        if (abort) {
            if (resultRecord != null) {
                resultStack.sendActivityResultLocked(-1, resultRecord, resultWho, requestCode,
                        Activity.RESULT_CANCELED, null);
            }
            // We pretend to the caller that it was really started, but
            // they will just get a cancel result.
            setDismissKeyguard(false);
            ActivityOptions.abort(options);
            return ActivityManager.START_SUCCESS;
        }

        ActivityRecord r = new ActivityRecord(mService, callerApp, callingUid, callingPackage,
                intent, resolvedType, aInfo, mService.mConfiguration,
                resultRecord, resultWho, requestCode, componentSpecified, this);
        if (outActivity != null) {
            outActivity[0] = r;
        }

        final ActivityStack stack = getFocusedStack();
        if (stack.mResumedActivity == null
                || stack.mResumedActivity.info.applicationInfo.uid != callingUid) {
            if (!mService.checkAppSwitchAllowedLocked(callingPid, callingUid, "Activity start")) {
                PendingActivityLaunch pal =
                        new PendingActivityLaunch(r, sourceRecord, startFlags, stack);
                mService.mPendingActivityLaunches.add(pal);
                setDismissKeyguard(false);
                ActivityOptions.abort(options);
                return ActivityManager.START_SWITCHES_CANCELED;
            }
        }

        if (mService.mDidAppSwitch) {
            // This is the second allowed switch since we stopped switches,
            // so now just generally allow switches.  Use case: user presses
            // home (switches disabled, switch to home, mDidAppSwitch now true);
            // user taps a home icon (coming from home so allowed, we hit here
            // and now allow anyone to switch again).
            mService.mAppSwitchesAllowedTime = 0;
        } else {
            mService.mDidAppSwitch = true;
        }

        mService.doPendingActivityLaunchesLocked(false);

        err = startActivityUncheckedLocked(r, sourceRecord, startFlags, true, options);

        if (allPausedActivitiesComplete()) {
            // If someone asked to have the keyguard dismissed on the next
            // activity start, but we are not actually doing an activity
            // switch...  just dismiss the keyguard now, because we
            // probably want to see whatever is behind it.
            dismissKeyguard();
        }
        return err;
    }

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final int startActivityLocked(IApplicationThread caller,

Intent intent, String resolvedType, ActivityInfo aInfo, IBinder resultTo,

String resultWho, int requestCode,

int callingPid, int callingUid, String callingPackage, int startFlags, Bundle options,

boolean componentSpecified, ActivityRecord[] outActivity) {

int err = ActivityManager.START_SUCCESS;

ProcessRecord callerApp = null;

if (caller != null) {

callerApp = mService.getRecordForAppLocked(caller);

if (callerApp != null) {

callingPid = callerApp.pid;

callingUid = callerApp.info.uid;

} else {

Slog.w(TAG, "Unable to find app for caller " + caller

+ " (pid=" + callingPid + ") when starting: "

+ intent.toString());

err = ActivityManager.START_PERMISSION_DENIED;

}

if (err == ActivityManager.START_SUCCESS) {

final int userId = aInfo != null ? UserHandle.getUserId(aInfo.applicationInfo.uid) : 0;

Slog.i(TAG, "START u" + userId + " {" + intent.toShortString(true, true, true, false)

+ "} from pid " + (callerApp != null ? callerApp.pid : callingPid));

}

ActivityRecord sourceRecord = null;

ActivityRecord resultRecord = null;

if (resultTo != null) {

sourceRecord = isInAnyStackLocked(resultTo);

if (DEBUG_RESULTS) Slog.v(

TAG, "Will send result to " + resultTo + " " + sourceRecord);

if (sourceRecord != null) {

if (requestCode >= 0 && !sourceRecord.finishing) {

resultRecord = sourceRecord;

}

ActivityStack resultStack = resultRecord == null ? null : resultRecord.task.stack;

int launchFlags = intent.getFlags();

if ((launchFlags&Intent.FLAG_ACTIVITY_FORWARD_RESULT) != 0

&& sourceRecord != null) {

// Transfer the result target from the source activity to the new

// one being started, including any failures.

if (requestCode >= 0) {

ActivityOptions.abort(options);

return ActivityManager.START_FORWARD_AND_REQUEST_CONFLICT;

}

resultRecord = sourceRecord.resultTo;

resultWho = sourceRecord.resultWho;

requestCode = sourceRecord.requestCode;

sourceRecord.resultTo = null;

if (resultRecord != null) {

resultRecord.removeResultsLocked(

sourceRecord, resultWho, requestCode);

}

if (sourceRecord.launchedFromUid == callingUid) {

// The new activity is being launched from the same uid as the previous

// activity in the flow, and asking to forward its result back to the

// previous. In this case the activity is serving as a trampoline between

// the two, so we also want to update its launchedFromPackage to be the

// same as the previous activity. Note that this is safe, since we know

// these two packages come from the same uid; the caller could just as

// well have supplied that same package name itself. This specifially

// deals with the case of an intent picker/chooser being launched in the app

// flow to redirect to an activity picked by the user, where we want the final

// activity to consider it to have been launched by the previous app activity.

callingPackage = sourceRecord.launchedFromPackage;

}

if (err == ActivityManager.START_SUCCESS && intent.getComponent() == null) {

// We couldn't find a class that can handle the given Intent.

// That's the end of that!

err = ActivityManager.START_INTENT_NOT_RESOLVED;

}

if (err == ActivityManager.START_SUCCESS && aInfo == null) {

// We couldn't find the specific class specified in the Intent.

// Also the end of the line.

err = ActivityManager.START_CLASS_NOT_FOUND;

}

if (err != ActivityManager.START_SUCCESS) {

if (resultRecord != null) {

resultStack.sendActivityResultLocked(-1,

resultRecord, resultWho, requestCode,

Activity.RESULT_CANCELED, null);

}

setDismissKeyguard(false);

ActivityOptions.abort(options);

return err;

}

final int startAnyPerm = mService.checkPermission(

START_ANY_ACTIVITY, callingPid, callingUid);

final int componentPerm = mService.checkComponentPermission(aInfo.permission, callingPid,

callingUid, aInfo.applicationInfo.uid, aInfo.exported);

if (startAnyPerm != PERMISSION_GRANTED && componentPerm != PERMISSION_GRANTED) {

if (resultRecord != null) {

resultStack.sendActivityResultLocked(-1,

resultRecord, resultWho, requestCode,

Activity.RESULT_CANCELED, null);

}

setDismissKeyguard(false);

String msg;

if (!aInfo.exported) {

msg = "Permission Denial: starting " + intent.toString()

+ " from " + callerApp + " (pid=" + callingPid

+ ", uid=" + callingUid + ")"

+ " not exported from uid " + aInfo.applicationInfo.uid;

} else {

msg = "Permission Denial: starting " + intent.toString()

+ " from " + callerApp + " (pid=" + callingPid

+ ", uid=" + callingUid + ")"

+ " requires " + aInfo.permission;

}

Slog.w(TAG, msg);

throw new SecurityException(msg);

}

boolean abort = !mService.mIntentFirewall.checkStartActivity(intent, callingUid,

callingPid, resolvedType, aInfo.applicationInfo);

if (mService.mController != null) {

try {

// The Intent we give to the watcher has the extra data

// stripped off, since it can contain private information.

Intent watchIntent = intent.cloneFilter();

abort |= !mService.mController.activityStarting(watchIntent,

aInfo.applicationInfo.packageName);

} catch (RemoteException e) {

mService.mController = null;

}

if (abort) {

if (resultRecord != null) {

resultStack.sendActivityResultLocked(-1, resultRecord, resultWho, requestCode,

Activity.RESULT_CANCELED, null);

}

// We pretend to the caller that it was really started, but

// they will just get a cancel result.

setDismissKeyguard(false);

ActivityOptions.abort(options);

return ActivityManager.START_SUCCESS;

}

ActivityRecord r = new ActivityRecord(mService, callerApp, callingUid, callingPackage,

intent, resolvedType, aInfo, mService.mConfiguration,

resultRecord, resultWho, requestCode, componentSpecified, this);

if (outActivity != null) {

outActivity[0] = r;

}

final ActivityStack stack = getFocusedStack();

if (stack.mResumedActivity == null

|| stack.mResumedActivity.info.applicationInfo.uid != callingUid) {

if (!mService.checkAppSwitchAllowedLocked(callingPid, callingUid, "Activity start")) {

PendingActivityLaunch pal =

new PendingActivityLaunch(r, sourceRecord, startFlags, stack);

mService.mPendingActivityLaunches.add(pal);

setDismissKeyguard(false);

ActivityOptions.abort(options);

return ActivityManager.START_SWITCHES_CANCELED;

}

if (mService.mDidAppSwitch) {

// This is the second allowed switch since we stopped switches,

// so now just generally allow switches. Use case: user presses

// home (switches disabled, switch to home, mDidAppSwitch now true);

// user taps a home icon (coming from home so allowed, we hit here

// and now allow anyone to switch again).

mService.mAppSwitchesAllowedTime = 0;

} else {

mService.mDidAppSwitch = true;

}

mService.doPendingActivityLaunchesLocked(false);

err = startActivityUncheckedLocked(r, sourceRecord, startFlags, true, options);

if (allPausedActivitiesComplete()) {

// If someone asked to have the keyguard dismissed on the next

// activity start, but we are not actually doing an activity

// switch... just dismiss the keyguard now, because we

// probably want to see whatever is behind it.

dismissKeyguard();

}

return err;

}

调用函数mStackSupervisor.startActivityUncheckedLocked

调用函数ActiviyManagerService.checkGrantUriPermissionFromIntentLocked

调用函数ActivityStack.startActivityLocked

调用WindowManagerService.prepareAppTransition

调用函数ActivityStack.resumeTopActivityLocked

调用函数ActivityStack.startPausingLocked 开始pause当前Activity

调用函数ActivityManagerService.updateUsageStats 更新电池电量统计

调用函数mStackSupervisor.setFocusedStack

    void setFocusedStack(ActivityRecord r) {
        if (r == null) {
            return;
        }
        if (!r.isApplicationActivity() || (r.task != null && !r.task.isApplicationTask())) {
            if (mStackState != STACK_STATE_HOME_IN_FRONT) {
                if (DEBUG_STACK || DEBUG_FOCUS) Slog.d(TAG, "setFocusedStack: mStackState old=" +
                        stackStateToString(mStackState) + " new=" +
                        stackStateToString(STACK_STATE_HOME_TO_FRONT) +
                        " Callers=" + Debug.getCallers(3));
                mStackState = STACK_STATE_HOME_TO_FRONT;
            }
        } else {
            if (DEBUG_FOCUS || DEBUG_STACK) Slog.d(TAG,
                    "setFocusedStack: Setting focused stack to r=" + r + " task=" + r.task +
                    " Callers=" + Debug.getCallers(3));
            final ActivityStack taskStack = r.task.stack;
            mFocusedStack = taskStack.isHomeStack() ? null : taskStack;
            if (mStackState != STACK_STATE_HOME_IN_BACK) {
                if (DEBUG_STACK) Slog.d(TAG, "setFocusedStack: mStackState old=" +
                        stackStateToString(mStackState) + " new=" +
                        stackStateToString(STACK_STATE_HOME_TO_BACK) +
                        " Callers=" + Debug.getCallers(3));
                mStackState = STACK_STATE_HOME_TO_BACK;
            }
        }
    }

void setFocusedStack(ActivityRecord r) {

if (r == null) {

return;

}

if (!r.isApplicationActivity() || (r.task != null && !r.task.isApplicationTask())) {

if (mStackState != STACK_STATE_HOME_IN_FRONT) {

if (DEBUG_STACK || DEBUG_FOCUS) Slog.d(TAG, "setFocusedStack: mStackState old=" +

stackStateToString(mStackState) + " new=" +

stackStateToString(STACK_STATE_HOME_TO_FRONT) +

" Callers=" + Debug.getCallers(3));

mStackState = STACK_STATE_HOME_TO_FRONT;

}

} else {

if (DEBUG_FOCUS || DEBUG_STACK) Slog.d(TAG,

"setFocusedStack: Setting focused stack to r=" + r + " task=" + r.task +

" Callers=" + Debug.getCallers(3));

final ActivityStack taskStack = r.task.stack;

mFocusedStack = taskStack.isHomeStack() ? null : taskStack;

if (mStackState != STACK_STATE_HOME_IN_BACK) {

if (DEBUG_STACK) Slog.d(TAG, "setFocusedStack: mStackState old=" +

stackStateToString(mStackState) + " new=" +

stackStateToString(STACK_STATE_HOME_TO_BACK) +

" Callers=" + Debug.getCallers(3));

mStackState = STACK_STATE_HOME_TO_BACK;

}

调用WindowManagerService.findFocusedWindowLocked

调用函数WindowManagerService.updateFocusedWindowLocked

调用函数：mStackSupervisor.allPausedActivitiesComplete

对HandlerThread的理解

分类：Android, Java 阅读 (2,075) 1 Response »

2月 202017

１．什么场景下需要使用HandlerThread

1). 比较耗时，不易于放在主线程中执行的操作（不考虑第２点使用其他线程方式也可以）

2). 有多个耗时操作需要后台执行（如果不嫌麻烦也可以考虑使用多个TThread）

２．HandlerThread的使用步骤

1). 创建HandlerThread对象

2). 执行start方法，启动HandlerThread的Looper循环

3). 在主线程中创建Handler对象并引用HandlerTherad的looper

4). 在Handler对象中加入各种消息的处理

5). 在需要的时候给步骤３创建的Handler对象发送消息

6). 不再需要HandlerThread的时候调用quit或者quitSafely停止HandlerThread

示例代码如下(没做各种错误处理，仅供参考)：

public class MainActivity extends AppCompatActivity {

    private Handler handler;
    private HandlerThread myHandlerThread ;
    private final int MSG_DOWNLOAD = 1;
    private final int MSG_DOWNLOAD2 = 2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        myHandlerThread = new HandlerThread("test_thread");
        // 这一步很重要
        myHandlerThread.start();
        handler = new Handler(myHandlerThread.getLooper()){
            @Override
            public void handleMessage(Message msg) {
                OkHttpClient client = new OkHttpClient();
                super.handleMessage(msg);
                switch (msg.what){
                    case MSG_DOWNLOAD:

                        Request request = new Request.Builder()
                                .url("http://baidu.com")
                                .build();

                        try {
                            Response response = client.newCall(request).execute();
                            Log.d("DOWNLOAD", response.body().string());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        break;
                    case MSG_DOWNLOAD2:
                        Request request1 = new Request.Builder()
                                .url("http://bcoder.com")
                                .build();

                        try {
                            Response response = client.newCall(request1).execute();
                            Log.d("DOWNLOAD", response.body().string());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        break;
                }
            }
        }; ;
    }

    public void onDownload1Click(View v){
        handler.sendEmptyMessage(MSG_DOWNLOAD);
    }

    public void onDownload2Click(View v){
        handler.sendEmptyMessage(MSG_DOWNLOAD2);
    }

    public void onQuitClick(View v){
        myHandlerThread.quit();
    }
}

public class MainActivity extends AppCompatActivity {

private Handler handler;

private HandlerThread myHandlerThread ;

private final int MSG_DOWNLOAD = 1;

private final int MSG_DOWNLOAD2 = 2;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

myHandlerThread = new HandlerThread("test_thread");

// 这一步很重要

myHandlerThread.start();

handler = new Handler(myHandlerThread.getLooper()){

@Override

public void handleMessage(Message msg) {

OkHttpClient client = new OkHttpClient();

super.handleMessage(msg);

switch (msg.what){

case MSG_DOWNLOAD:

Request request = new Request.Builder()

.url("http://baidu.com")

.build();

try {

Response response = client.newCall(request).execute();

Log.d("DOWNLOAD", response.body().string());

} catch (IOException e) {

e.printStackTrace();

}

break;

case MSG_DOWNLOAD2:

Request request1 = new Request.Builder()

.url("http://bcoder.com")

.build();

try {

Response response = client.newCall(request1).execute();

Log.d("DOWNLOAD", response.body().string());

} catch (IOException e) {

e.printStackTrace();

}

break;

}

}; ;

}

public void onDownload1Click(View v){

handler.sendEmptyMessage(MSG_DOWNLOAD);

}

public void onDownload2Click(View v){

handler.sendEmptyMessage(MSG_DOWNLOAD2);

}

public void onQuitClick(View v){

myHandlerThread.quit();

}

测试时多次点击Download1和Download2按钮，handler对象就会按点击的顺序多次下载网页baid.com和bcoder.com

3. 要不要像Thread那样写一个HandlerThread的子类？

完全没有必要，因为真正程序执行部分都在handler的消息处理里

4. quit和quitSafely的区别？

5. HandlerThread的其它特点

1). HandlerThread中的多个操作是串行按序执行的，即任务１＼任务２＼任务３．．．．，所以如果你想尽早的获得运行结果，不建议使用HandlerThread这种方式

6. 测试代码下载

LocaleTest

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