Android – 第3页 – 蓝天白云

Android中art虚拟机启动流程

分类：Android, Java 阅读 (1,589) 已关闭评论

7月 072020

本文基于Android8.1系统进行研究

一、启动zygote

在Linux内核启动完成后，首先启动系统的第一个进程init进程

init进程会读取init.rc中的配置文件

其中有Zygote的配置，init进程将启动zygote进程

zygote的入口在app_main.cpp中的main函数中

二、解析传入参数，调用AndroidRuntime的start方法

在app_main.cpp中的main函数中，首先解析传入的相关参数，并通过如下代码进入ZygoteInit的main函数中

    if (zygote) {
        runtime.start("com.android.internal.os.ZygoteInit", args, zygote);
    }

if (zygote) {

runtime.start("com.android.internal.os.ZygoteInit", args, zygote);

}

runtime是AppRuntime的一个实例，AppRuntim继承自AndroidRuntime

start函数定义在AndroidRuntime中，下面是start函数的注释

/*
 * Start the Android runtime.  This involves starting the virtual machine
 * and calling the "static void main(String[] args)" method in the class
 * named by "className".
 *
 * Passes the main function two arguments, the class name and the specified
 * options string.
*
* 翻译：
* 启动Android运行时，包括启动虚拟机，调用className参数对应的main函数
 */

* Start the Android runtime. This involves starting the virtual machine

* and calling the "static void main(String[] args)" method in the class

* named by "className".

* Passes the main function two arguments, the class name and the specified

* options string.

* 翻译：

* 启动Android运行时，包括启动虚拟机，调用className参数对应的main函数

start函数中的这段代码切入到了startVm函数中

    /* start the virtual machine */
    JniInvocation jni_invocation;
    jni_invocation.Init(NULL);
    JNIEnv* env;
    if (startVm(&mJavaVM, &env, zygote) != 0) {
        return;
    }
    onVmCreated(env);

/* start the virtual machine */

JniInvocation jni_invocation;

jni_invocation.Init(NULL);

JNIEnv* env;

if (startVm(&mJavaVM, &env, zygote) != 0) {

return;

}

onVmCreated(env);

三、startVm函数

这个函数前边也是一堆处理Vm启动参数的逻辑

在函数的最好调用JNI_CreateJavaVM函数通过c++层的库创建虚拟机

四、JNI_CreateJavaVM函数

JNI_CreateJavaVM函数是在art/runtime/java_vm_ext.cc中实现的，代码如下：

// JNI Invocation interface.

extern "C" jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
  ScopedTrace trace(__FUNCTION__);
  const JavaVMInitArgs* args = static_cast<JavaVMInitArgs*>(vm_args);
  if (JavaVMExt::IsBadJniVersion(args->version)) {
    LOG(ERROR) << "Bad JNI version passed to CreateJavaVM: " << args->version;
    return JNI_EVERSION;
  }
  RuntimeOptions options;
  for (int i = 0; i < args->nOptions; ++i) {
    JavaVMOption* option = &args->options[i];
    options.push_back(std::make_pair(std::string(option->optionString), option->extraInfo));
  }
  bool ignore_unrecognized = args->ignoreUnrecognized;
  if (!Runtime::Create(options, ignore_unrecognized)) {
    return JNI_ERR;
  }

  // Initialize native loader. This step makes sure we have
  // everything set up before we start using JNI.
  android::InitializeNativeLoader();

  Runtime* runtime = Runtime::Current();
  bool started = runtime->Start();
  if (!started) {
    delete Thread::Current()->GetJniEnv();
    delete runtime->GetJavaVM();
    LOG(WARNING) << "CreateJavaVM failed";
    return JNI_ERR;
  }

  *p_env = Thread::Current()->GetJniEnv();
  *p_vm = runtime->GetJavaVM();
  return JNI_OK;
}

// JNI Invocation interface.

extern "C" jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {

ScopedTrace trace(__FUNCTION__);

const JavaVMInitArgs* args = static_cast<JavaVMInitArgs*>(vm_args);

if (JavaVMExt::IsBadJniVersion(args->version)) {

LOG(ERROR) << "Bad JNI version passed to CreateJavaVM: " << args->version;

return JNI_EVERSION;

}

RuntimeOptions options;

for (int i = 0; i < args->nOptions; ++i) {

JavaVMOption* option = &args->options[i];

options.push_back(std::make_pair(std::string(option->optionString), option->extraInfo));

}

bool ignore_unrecognized = args->ignoreUnrecognized;

if (!Runtime::Create(options, ignore_unrecognized)) {

return JNI_ERR;

}

// Initialize native loader. This step makes sure we have

// everything set up before we start using JNI.

android::InitializeNativeLoader();

Runtime* runtime = Runtime::Current();

bool started = runtime->Start();

if (!started) {

delete Thread::Current()->GetJniEnv();

delete runtime->GetJavaVM();

LOG(WARNING) << "CreateJavaVM failed";

return JNI_ERR;

}

*p_env = Thread::Current()->GetJniEnv();

*p_vm = runtime->GetJavaVM();

return JNI_OK;

}

Runtime是在art/runtime/runtime.h中定义的类

Runtime::Current()返回一个静态的Runtime实例，代码如下：

static Runtime* instance_;

1	static Runtime* instance_;

runtime-Start()启动虚拟机

五、其他参考文章

Android ART运行时无缝替换Dalvik虚拟机的过程分析

https://blog.csdn.net/zhu929033262/article/details/77053640

Android虚拟机art流程：从zygote开始梳理art的启动（1）

https://www.shennongblog.com/art-zygote/

Flutter报Could not resolve io.flutter:flutter_embedding_debug问题解决

分类：Android, Java 阅读 (2,756) 已关闭评论

6月 132020

解决办法：

打开build.gradle文件，增加如下maven仓库地址：

文字版：

buildscript {
    ext.kotlin_version = '1.3.50'
    repositories {
        google()
        jcenter()
        maven { url "http://download.flutter.io" } //这里增加
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        maven { url "http://download.flutter.io" } //这里增加
    }
}

buildscript {

ext.kotlin_version = '1.3.50'

repositories {

google()

jcenter()

maven { url "http://download.flutter.io" } //这里增加

}

dependencies {

classpath 'com.android.tools.build:gradle:3.5.0'

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

}

allprojects {

repositories {

google()

jcenter()

maven { url "http://download.flutter.io" } //这里增加

}

Activity的onSaveInstanceState方法的官方解释

分类：Android, Java 阅读 (1,093) 已关闭评论

6月 032020

基于Android8.1系统源码中的注释翻译

翻译如下：

　　在一个Activity被杀死之前被调用以取出Activity中每个对象实例的状态，这些状态可以在onCreate或者onRestoreInstanceState方法中被重新加载到实例（此方法产生的Bundle将传递到那两个方法）。

　　这个方法在一个Activity可能被杀掉之前（不是刚刚被杀之前）被调用，以便于之后某些时候Activity被重新打开时可以恢复它的（某些变量的）状态。比如，如果ActivityB被打开并显示在ActivityA之前（ActivityA被置于后台），在某些时候ActivityA由于系统资源回收被杀掉，AvtivityA将有机会使用此方法来保存用户界面的当前状态，以便当用户回到ActivityA时，用户界面的状态可以在Activity的onCreate或者onRestoreInstanceState中被恢复。

　　不要把这个方法和Activity的生命周期比如onPause和onStop混淆。比如，当从ActivityB退出返回到ActivityA时，onPause和onStop将被调用，但是onSaveInstanceState不会被调用，此时没有必要对ActivityB调用此方法，因为ActivityB将被销毁，并且不会被恢复。另外一个例子，当ActivityB被打开并显示在ActivityA之前时，系统可能会避免调用ActivityA的onSaveInstanceState方法，因为在ActivityB的生命周期内，ActivityA的ui状态可能一直保持完整。

　　大部分UI组件的实例的（状态保存）默认实现是通过对布局中有id属性的view调用view自身的onSaveInstanceState()方法，通过id保存当前有焦点的view（通过view的onRestoreInstanceState来恢复状态）。如果你想使用这个方法来保存某个view的状态，最好使用view自身的onSaveInstanceState来处理，否则每个（Activity中）的view实例都需要你写代码来维护。

　　如果此方法被调用，将在onStop之前发生，但是不能保证肯定是在onPause之后发生。

原文如下：

    /**
     * Called to retrieve per-instance state from an activity before being killed
     * so that the state can be restored in {@link #onCreate} or
     * {@link #onRestoreInstanceState} (the {@link Bundle} populated by this method
     * will be passed to both).
     *
     * <p>This method is called before an activity may be killed so that when it
     * comes back some time in the future it can restore its state.  For example,
     * if activity B is launched in front of activity A, and at some point activity
     * A is killed to reclaim resources, activity A will have a chance to save the
     * current state of its user interface via this method so that when the user
     * returns to activity A, the state of the user interface can be restored
     * via {@link #onCreate} or {@link #onRestoreInstanceState}.
     *
     * <p>Do not confuse this method with activity lifecycle callbacks such as
     * {@link #onPause}, which is always called when an activity is being placed
     * in the background or on its way to destruction, or {@link #onStop} which
     * is called before destruction.  One example of when {@link #onPause} and
     * {@link #onStop} is called and not this method is when a user navigates back
     * from activity B to activity A: there is no need to call {@link #onSaveInstanceState}
     * on B because that particular instance will never be restored, so the
     * system avoids calling it.  An example when {@link #onPause} is called and
     * not {@link #onSaveInstanceState} is when activity B is launched in front of activity A:
     * the system may avoid calling {@link #onSaveInstanceState} on activity A if it isn't
     * killed during the lifetime of B since the state of the user interface of
     * A will stay intact.
     *
     * <p>The default implementation takes care of most of the UI per-instance
     * state for you by calling {@link android.view.View#onSaveInstanceState()} on each
     * view in the hierarchy that has an id, and by saving the id of the currently
     * focused view (all of which is restored by the default implementation of
     * {@link #onRestoreInstanceState}).  If you override this method to save additional
     * information not captured by each individual view, you will likely want to
     * call through to the default implementation, otherwise be prepared to save
     * all of the state of each view yourself.
     *
     * <p>If called, this method will occur before {@link #onStop}.  There are
     * no guarantees about whether it will occur before or after {@link #onPause}.
     *
     * @param outState Bundle in which to place your saved state.
     *
     * @see #onCreate
     * @see #onRestoreInstanceState
     * @see #onPause
     */

/**

* Called to retrieve per-instance state from an activity before being killed

* so that the state can be restored in {@link #onCreate} or

* {@link #onRestoreInstanceState} (the {@link Bundle} populated by this method

* will be passed to both).

* <p>This method is called before an activity may be killed so that when it

* comes back some time in the future it can restore its state. For example,

* if activity B is launched in front of activity A, and at some point activity

* A is killed to reclaim resources, activity A will have a chance to save the

* current state of its user interface via this method so that when the user

* returns to activity A, the state of the user interface can be restored

* via {@link #onCreate} or {@link #onRestoreInstanceState}.

* <p>Do not confuse this method with activity lifecycle callbacks such as

* {@link #onPause}, which is always called when an activity is being placed

* in the background or on its way to destruction, or {@link #onStop} which

* is called before destruction. One example of when {@link #onPause} and

* {@link #onStop} is called and not this method is when a user navigates back

* from activity B to activity A: there is no need to call {@link #onSaveInstanceState}

* on B because that particular instance will never be restored, so the

* system avoids calling it. An example when {@link #onPause} is called and

* not {@link #onSaveInstanceState} is when activity B is launched in front of activity A:

* the system may avoid calling {@link #onSaveInstanceState} on activity A if it isn't

* killed during the lifetime of B since the state of the user interface of

* A will stay intact.

* <p>The default implementation takes care of most of the UI per-instance

* state for you by calling {@link android.view.View#onSaveInstanceState()} on each

* view in the hierarchy that has an id, and by saving the id of the currently

* focused view (all of which is restored by the default implementation of

* {@link #onRestoreInstanceState}). If you override this method to save additional

* information not captured by each individual view, you will likely want to

* call through to the default implementation, otherwise be prepared to save

* all of the state of each view yourself.

* <p>If called, this method will occur before {@link #onStop}. There are

* no guarantees about whether it will occur before or after {@link #onPause}.

* @param outState Bundle in which to place your saved state.

* @see #onCreate

* @see #onRestoreInstanceState

* @see #onPause

顶栏phone.StatusBar中makeStatusBarView函数分析（未完）

分类：Android, Java 阅读 (1,529) 已关闭评论

6月 012020

本文基于Android8.1系统

    protected void makeStatusBarView() {
        final Context context = mContext;
        // 用于重新获取mDisplayMetrics和mCurrentDisplaySize
        updateDisplaySize(); // populates mDisplayMetrics
        // 重新加载QSPanel、NotificationPanel等的资源，因为可能configuration可能会有变化
        updateResources();
        updateTheme();

        // 用布局R.layout.super_status_bar填充mStatusBarWindow
        inflateStatusBarWindow(context);
        mStatusBarWindow.setService(this);
        mStatusBarWindow.setOnTouchListener(getStatusBarWindowTouchListener());

        // mNotificationPanel用于显示各种各种通知的根Panel
        // TODO: Deal with the ugliness that comes from having some of the statusbar broken out
        // into fragments, but the rest here, it leaves some awkward lifecycle and whatnot.
        mNotificationPanel = (NotificationPanelView) mStatusBarWindow.findViewById(
                R.id.notification_panel);
        // mStackScroller用于显示列表形式的系统通知
        mStackScroller = (NotificationStackScrollLayout) mStatusBarWindow.findViewById(
                R.id.notification_stack_scroller);
        mNotificationPanel.setStatusBar(this);
        mNotificationPanel.setGroupManager(mGroupManager);
        mAboveShelfObserver = new AboveShelfObserver(mStackScroller);
        mAboveShelfObserver.setListener(mStatusBarWindow.findViewById(
                R.id.notification_container_parent));
        mKeyguardStatusBar = (KeyguardStatusBarView) mStatusBarWindow.findViewById(R.id.keyguard_header);

        mNotificationIconAreaController = SystemUIFactory.getInstance()
                .createNotificationIconAreaController(context, this);
        inflateShelf();
        mNotificationIconAreaController.setupShelf(mNotificationShelf);
        Dependency.get(DarkIconDispatcher.class).addDarkReceiver(mNotificationIconAreaController);
        FragmentHostManager.get(mStatusBarWindow)
                .addTagListener(CollapsedStatusBarFragment.TAG, (tag, fragment) -> {
                    CollapsedStatusBarFragment statusBarFragment =
                            (CollapsedStatusBarFragment) fragment;
                    statusBarFragment.initNotificationIconArea(mNotificationIconAreaController);
                    mStatusBarView = (PhoneStatusBarView) fragment.getView();
                    mStatusBarView.setBar(this);
                    mStatusBarView.setPanel(mNotificationPanel);
                    mStatusBarView.setScrimController(mScrimController);
                    mStatusBarView.setBouncerShowing(mBouncerShowing);
                    setAreThereNotifications();
                    checkBarModes();
                }).getFragmentManager()
                .beginTransaction()
                .replace(R.id.status_bar_container, new CollapsedStatusBarFragment(),
                        CollapsedStatusBarFragment.TAG)
                .commit();
        mIconController = Dependency.get(StatusBarIconController.class);

        mHeadsUpManager = new HeadsUpManager(context, mStatusBarWindow, mGroupManager);
        mHeadsUpManager.setBar(this);
        mHeadsUpManager.addListener(this);
        mHeadsUpManager.addListener(mNotificationPanel);
        mHeadsUpManager.addListener(mGroupManager);
        mHeadsUpManager.addListener(mVisualStabilityManager);
        mNotificationPanel.setHeadsUpManager(mHeadsUpManager);
        mNotificationData.setHeadsUpManager(mHeadsUpManager);
        mGroupManager.setHeadsUpManager(mHeadsUpManager);
        mHeadsUpManager.setVisualStabilityManager(mVisualStabilityManager);

        if (MULTIUSER_DEBUG) {
            mNotificationPanelDebugText = (TextView) mNotificationPanel.findViewById(
                    R.id.header_debug_info);
            mNotificationPanelDebugText.setVisibility(View.VISIBLE);
        }

        try {
            boolean showNav = mWindowManagerService.hasNavigationBar();
            if (DEBUG) Log.v(TAG, "hasNavigationBar=" + showNav);
            if (showNav) {
                createNavigationBar();
            }
        } catch (RemoteException ex) {
            // no window manager? good luck with that
        }

        // figure out which pixel-format to use for the status bar.
        mPixelFormat = PixelFormat.OPAQUE;

        // 通知列表框
        mStackScroller.setLongPressListener(getNotificationLongClicker());
        mStackScroller.setStatusBar(this);
        mStackScroller.setGroupManager(mGroupManager);
        mStackScroller.setHeadsUpManager(mHeadsUpManager);
        mGroupManager.setOnGroupChangeListener(mStackScroller);
        mVisualStabilityManager.setVisibilityLocationProvider(mStackScroller);

        // 没有通知提示框
        inflateEmptyShadeView();
        // 清除所有通知提示框
        inflateDismissView();
        mExpandedContents = mStackScroller;

        // 包含多媒体插图、图片的View？不知道是干啥用的
        mBackdrop = (BackDropView) mStatusBarWindow.findViewById(R.id.backdrop);
        mBackdropFront = (ImageView) mBackdrop.findViewById(R.id.backdrop_front);
        mBackdropBack = (ImageView) mBackdrop.findViewById(R.id.backdrop_back);

        // 字面翻译：锁屏壁纸
        if (ENABLE_LOCKSCREEN_WALLPAPER) {
            mLockscreenWallpaper = new LockscreenWallpaper(mContext, this, mHandler);
        }

        mKeyguardIndicationController =
                SystemUIFactory.getInstance().createKeyguardIndicationController(mContext,
                (ViewGroup) mStatusBarWindow.findViewById(R.id.keyguard_indication_area),
                mNotificationPanel.getLockIcon());
        mNotificationPanel.setKeyguardIndicationController(mKeyguardIndicationController);


        mAmbientIndicationContainer = mStatusBarWindow.findViewById(
                R.id.ambient_indication_container);

        // set the initial view visibility
        setAreThereNotifications();

        // TODO: Find better place for this callback.
        mBatteryController.addCallback(new BatteryStateChangeCallback() {
            @Override
            public void onPowerSaveChanged(boolean isPowerSave) {
                mHandler.post(mCheckBarModes);
                if (mDozeServiceHost != null) {
                    mDozeServiceHost.firePowerSaveChanged(isPowerSave);
                }
            }

            @Override
            public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {
                // noop
            }
        });

        mLightBarController = Dependency.get(LightBarController.class);
        if (mNavigationBar != null) {
            mNavigationBar.setLightBarController(mLightBarController);
        }

        ScrimView scrimBehind = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_behind);
        ScrimView scrimInFront = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_in_front);
        View headsUpScrim = mStatusBarWindow.findViewById(R.id.heads_up_scrim);
        mScrimController = SystemUIFactory.getInstance().createScrimController(mLightBarController,
                scrimBehind, scrimInFront, headsUpScrim, mLockscreenWallpaper,
                scrimsVisible -> {
                    if (mStatusBarWindowManager != null) {
                        mStatusBarWindowManager.setScrimsVisible(scrimsVisible);
                    }
                });
        if (mScrimSrcModeEnabled) {
            Runnable runnable = new Runnable() {
                @Override
                public void run() {
                    boolean asSrc = mBackdrop.getVisibility() != View.VISIBLE;
                    mScrimController.setDrawBehindAsSrc(asSrc);
                    mStackScroller.setDrawBackgroundAsSrc(asSrc);
                }
            };
            mBackdrop.setOnVisibilityChangedRunnable(runnable);
            runnable.run();
        }
        mHeadsUpManager.addListener(mScrimController);
        mStackScroller.setScrimController(mScrimController);
        mDozeScrimController = new DozeScrimController(mScrimController, context);

        // Other icons
        mVolumeComponent = getComponent(VolumeComponent.class);

        mNotificationPanel.setUserSetupComplete(mUserSetup);
        if (UserManager.get(mContext).isUserSwitcherEnabled()) {
            createUserSwitcher();
        }

        // 配置快速设置小按钮的面板
        View container = mStatusBarWindow.findViewById(R.id.qs_frame);
        if (container != null) {
            FragmentHostManager fragmentHostManager = FragmentHostManager.get(container);
            ExtensionFragmentListener.attachExtensonToFragment(container, QS.TAG, R.id.qs_frame,
                    Dependency.get(ExtensionController.class).newExtension(QS.class)
                            .withPlugin(QS.class)
                            .withFeature(
                                    PackageManager.FEATURE_AUTOMOTIVE, () -> new CarQSFragment())
                            .withDefault(() -> new QSFragment())
                            .build());
            final QSTileHost qsh = SystemUIFactory.getInstance().createQSTileHost(mContext, this,
                    mIconController);
            mBrightnessMirrorController = new BrightnessMirrorController(mStatusBarWindow,
                    mScrimController);
            fragmentHostManager.addTagListener(QS.TAG, (tag, f) -> {
                QS qs = (QS) f;
                if (qs instanceof QSFragment) {
                    ((QSFragment) qs).setHost(qsh);
                    mQSPanel = ((QSFragment) qs).getQsPanel();
                    mQSPanel.setBrightnessMirror(mBrightnessMirrorController);
                    mKeyguardStatusBar.setQSPanel(mQSPanel);
                }
            });
        }

        mReportRejectedTouch = mStatusBarWindow.findViewById(R.id.report_rejected_touch);
        if (mReportRejectedTouch != null) {
            updateReportRejectedTouchVisibility();
            mReportRejectedTouch.setOnClickListener(v -> {
                Uri session = mFalsingManager.reportRejectedTouch();
                if (session == null) { return; }

                StringWriter message = new StringWriter();
                message.write("Build info: ");
                message.write(SystemProperties.get("ro.build.description"));
                message.write("\nSerial number: ");
                message.write(SystemProperties.get("ro.serialno"));
                message.write("\n");

                PrintWriter falsingPw = new PrintWriter(message);
                FalsingLog.dump(falsingPw);
                falsingPw.flush();

                startActivityDismissingKeyguard(Intent.createChooser(new Intent(Intent.ACTION_SEND)
                                .setType("*/*")
                                .putExtra(Intent.EXTRA_SUBJECT, "Rejected touch report")
                                .putExtra(Intent.EXTRA_STREAM, session)
                                .putExtra(Intent.EXTRA_TEXT, message.toString()),
                        "Share rejected touch report")
                                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
                        true /* onlyProvisioned */, true /* dismissShade */);
            });
        }

        PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
        if (!pm.isScreenOn()) {
            mBroadcastReceiver.onReceive(mContext, new Intent(Intent.ACTION_SCREEN_OFF));
        }
        mGestureWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK,
                "GestureWakeLock");
        mVibrator = mContext.getSystemService(Vibrator.class);
        int[] pattern = mContext.getResources().getIntArray(
                R.array.config_cameraLaunchGestureVibePattern);
        mCameraLaunchGestureVibePattern = new long[pattern.length];
        for (int i = 0; i < pattern.length; i++) {
            mCameraLaunchGestureVibePattern[i] = pattern[i];
        }

        // receive broadcasts
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(DevicePolicyManager.ACTION_SHOW_DEVICE_MONITORING_DIALOG);
        context.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);

        IntentFilter demoFilter = new IntentFilter();
        if (DEBUG_MEDIA_FAKE_ARTWORK) {
            demoFilter.addAction(ACTION_FAKE_ARTWORK);
        }
        demoFilter.addAction(ACTION_DEMO);
        context.registerReceiverAsUser(mDemoReceiver, UserHandle.ALL, demoFilter,
                android.Manifest.permission.DUMP, null);

        // listen for USER_SETUP_COMPLETE setting (per-user)
        mDeviceProvisionedController.addCallback(mUserSetupObserver);
        mUserSetupObserver.onUserSetupChanged();

        // disable profiling bars, since they overlap and clutter the output on app windows
        ThreadedRenderer.overrideProperty("disableProfileBars", "true");

        // Private API call to make the shadows look better for Recents
        ThreadedRenderer.overrideProperty("ambientRatio", String.valueOf(1.5f));
    }

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protected void makeStatusBarView() {

final Context context = mContext;

// 用于重新获取mDisplayMetrics和mCurrentDisplaySize

updateDisplaySize(); // populates mDisplayMetrics

// 重新加载QSPanel、NotificationPanel等的资源，因为可能configuration可能会有变化

updateResources();

updateTheme();

// 用布局R.layout.super_status_bar填充mStatusBarWindow

inflateStatusBarWindow(context);

mStatusBarWindow.setService(this);

mStatusBarWindow.setOnTouchListener(getStatusBarWindowTouchListener());

// mNotificationPanel用于显示各种各种通知的根Panel

// TODO: Deal with the ugliness that comes from having some of the statusbar broken out

// into fragments, but the rest here, it leaves some awkward lifecycle and whatnot.

mNotificationPanel = (NotificationPanelView) mStatusBarWindow.findViewById(

R.id.notification_panel);

// mStackScroller用于显示列表形式的系统通知

mStackScroller = (NotificationStackScrollLayout) mStatusBarWindow.findViewById(

R.id.notification_stack_scroller);

mNotificationPanel.setStatusBar(this);

mNotificationPanel.setGroupManager(mGroupManager);

mAboveShelfObserver = new AboveShelfObserver(mStackScroller);

mAboveShelfObserver.setListener(mStatusBarWindow.findViewById(

R.id.notification_container_parent));

mKeyguardStatusBar = (KeyguardStatusBarView) mStatusBarWindow.findViewById(R.id.keyguard_header);

mNotificationIconAreaController = SystemUIFactory.getInstance()

.createNotificationIconAreaController(context, this);

inflateShelf();

mNotificationIconAreaController.setupShelf(mNotificationShelf);

Dependency.get(DarkIconDispatcher.class).addDarkReceiver(mNotificationIconAreaController);

FragmentHostManager.get(mStatusBarWindow)

.addTagListener(CollapsedStatusBarFragment.TAG, (tag, fragment) -> {

CollapsedStatusBarFragment statusBarFragment =

(CollapsedStatusBarFragment) fragment;

statusBarFragment.initNotificationIconArea(mNotificationIconAreaController);

mStatusBarView = (PhoneStatusBarView) fragment.getView();

mStatusBarView.setBar(this);

mStatusBarView.setPanel(mNotificationPanel);

mStatusBarView.setScrimController(mScrimController);

mStatusBarView.setBouncerShowing(mBouncerShowing);

setAreThereNotifications();

checkBarModes();

}).getFragmentManager()

.beginTransaction()

.replace(R.id.status_bar_container, new CollapsedStatusBarFragment(),

CollapsedStatusBarFragment.TAG)

.commit();

mIconController = Dependency.get(StatusBarIconController.class);

mHeadsUpManager = new HeadsUpManager(context, mStatusBarWindow, mGroupManager);

mHeadsUpManager.setBar(this);

mHeadsUpManager.addListener(this);

mHeadsUpManager.addListener(mNotificationPanel);

mHeadsUpManager.addListener(mGroupManager);

mHeadsUpManager.addListener(mVisualStabilityManager);

mNotificationPanel.setHeadsUpManager(mHeadsUpManager);

mNotificationData.setHeadsUpManager(mHeadsUpManager);

mGroupManager.setHeadsUpManager(mHeadsUpManager);

mHeadsUpManager.setVisualStabilityManager(mVisualStabilityManager);

if (MULTIUSER_DEBUG) {

mNotificationPanelDebugText = (TextView) mNotificationPanel.findViewById(

R.id.header_debug_info);

mNotificationPanelDebugText.setVisibility(View.VISIBLE);

}

try {

boolean showNav = mWindowManagerService.hasNavigationBar();

if (DEBUG) Log.v(TAG, "hasNavigationBar=" + showNav);

if (showNav) {

createNavigationBar();

}

} catch (RemoteException ex) {

// no window manager? good luck with that

}

// figure out which pixel-format to use for the status bar.

mPixelFormat = PixelFormat.OPAQUE;

// 通知列表框

mStackScroller.setLongPressListener(getNotificationLongClicker());

mStackScroller.setStatusBar(this);

mStackScroller.setGroupManager(mGroupManager);

mStackScroller.setHeadsUpManager(mHeadsUpManager);

mGroupManager.setOnGroupChangeListener(mStackScroller);

mVisualStabilityManager.setVisibilityLocationProvider(mStackScroller);

// 没有通知提示框

inflateEmptyShadeView();

// 清除所有通知提示框

inflateDismissView();

mExpandedContents = mStackScroller;

// 包含多媒体插图、图片的View？不知道是干啥用的

mBackdrop = (BackDropView) mStatusBarWindow.findViewById(R.id.backdrop);

mBackdropFront = (ImageView) mBackdrop.findViewById(R.id.backdrop_front);

mBackdropBack = (ImageView) mBackdrop.findViewById(R.id.backdrop_back);

// 字面翻译：锁屏壁纸

if (ENABLE_LOCKSCREEN_WALLPAPER) {

mLockscreenWallpaper = new LockscreenWallpaper(mContext, this, mHandler);

}

mKeyguardIndicationController =

SystemUIFactory.getInstance().createKeyguardIndicationController(mContext,

(ViewGroup) mStatusBarWindow.findViewById(R.id.keyguard_indication_area),

mNotificationPanel.getLockIcon());

mNotificationPanel.setKeyguardIndicationController(mKeyguardIndicationController);

mAmbientIndicationContainer = mStatusBarWindow.findViewById(

R.id.ambient_indication_container);

// set the initial view visibility

setAreThereNotifications();

// TODO: Find better place for this callback.

mBatteryController.addCallback(new BatteryStateChangeCallback() {

@Override

public void onPowerSaveChanged(boolean isPowerSave) {

mHandler.post(mCheckBarModes);

if (mDozeServiceHost != null) {

mDozeServiceHost.firePowerSaveChanged(isPowerSave);

}

@Override

public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {

// noop

}

});

mLightBarController = Dependency.get(LightBarController.class);

if (mNavigationBar != null) {

mNavigationBar.setLightBarController(mLightBarController);

}

ScrimView scrimBehind = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_behind);

ScrimView scrimInFront = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_in_front);

View headsUpScrim = mStatusBarWindow.findViewById(R.id.heads_up_scrim);

mScrimController = SystemUIFactory.getInstance().createScrimController(mLightBarController,

scrimBehind, scrimInFront, headsUpScrim, mLockscreenWallpaper,

scrimsVisible -> {

if (mStatusBarWindowManager != null) {

mStatusBarWindowManager.setScrimsVisible(scrimsVisible);

}

});

if (mScrimSrcModeEnabled) {

Runnable runnable = new Runnable() {

@Override

public void run() {

boolean asSrc = mBackdrop.getVisibility() != View.VISIBLE;

mScrimController.setDrawBehindAsSrc(asSrc);

mStackScroller.setDrawBackgroundAsSrc(asSrc);

}

};

mBackdrop.setOnVisibilityChangedRunnable(runnable);

runnable.run();

}

mHeadsUpManager.addListener(mScrimController);

mStackScroller.setScrimController(mScrimController);

mDozeScrimController = new DozeScrimController(mScrimController, context);

// Other icons

mVolumeComponent = getComponent(VolumeComponent.class);

mNotificationPanel.setUserSetupComplete(mUserSetup);

if (UserManager.get(mContext).isUserSwitcherEnabled()) {

createUserSwitcher();

}

// 配置快速设置小按钮的面板

View container = mStatusBarWindow.findViewById(R.id.qs_frame);

if (container != null) {

FragmentHostManager fragmentHostManager = FragmentHostManager.get(container);

ExtensionFragmentListener.attachExtensonToFragment(container, QS.TAG, R.id.qs_frame,

Dependency.get(ExtensionController.class).newExtension(QS.class)

.withPlugin(QS.class)

.withFeature(

PackageManager.FEATURE_AUTOMOTIVE, () -> new CarQSFragment())

.withDefault(() -> new QSFragment())

.build());

final QSTileHost qsh = SystemUIFactory.getInstance().createQSTileHost(mContext, this,

mIconController);

mBrightnessMirrorController = new BrightnessMirrorController(mStatusBarWindow,

mScrimController);

fragmentHostManager.addTagListener(QS.TAG, (tag, f) -> {

QS qs = (QS) f;

if (qs instanceof QSFragment) {

((QSFragment) qs).setHost(qsh);

mQSPanel = ((QSFragment) qs).getQsPanel();

mQSPanel.setBrightnessMirror(mBrightnessMirrorController);

mKeyguardStatusBar.setQSPanel(mQSPanel);

}

});

}

mReportRejectedTouch = mStatusBarWindow.findViewById(R.id.report_rejected_touch);

if (mReportRejectedTouch != null) {

updateReportRejectedTouchVisibility();

mReportRejectedTouch.setOnClickListener(v -> {

Uri session = mFalsingManager.reportRejectedTouch();

if (session == null) { return; }

StringWriter message = new StringWriter();

message.write("Build info: ");

message.write(SystemProperties.get("ro.build.description"));

message.write("\nSerial number: ");

message.write(SystemProperties.get("ro.serialno"));

message.write("\n");

PrintWriter falsingPw = new PrintWriter(message);

FalsingLog.dump(falsingPw);

falsingPw.flush();

startActivityDismissingKeyguard(Intent.createChooser(new Intent(Intent.ACTION_SEND)

.setType("*/*")

.putExtra(Intent.EXTRA_SUBJECT, "Rejected touch report")

.putExtra(Intent.EXTRA_STREAM, session)

.putExtra(Intent.EXTRA_TEXT, message.toString()),

"Share rejected touch report")

.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),

true /* onlyProvisioned */, true /* dismissShade */);

});

}

PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);

if (!pm.isScreenOn()) {

mBroadcastReceiver.onReceive(mContext, new Intent(Intent.ACTION_SCREEN_OFF));

}

mGestureWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK,

"GestureWakeLock");

mVibrator = mContext.getSystemService(Vibrator.class);

int[] pattern = mContext.getResources().getIntArray(

R.array.config_cameraLaunchGestureVibePattern);

mCameraLaunchGestureVibePattern = new long[pattern.length];

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

mCameraLaunchGestureVibePattern[i] = pattern[i];

}

// receive broadcasts

IntentFilter filter = new IntentFilter();

filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);

filter.addAction(Intent.ACTION_SCREEN_OFF);

filter.addAction(DevicePolicyManager.ACTION_SHOW_DEVICE_MONITORING_DIALOG);

context.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);

IntentFilter demoFilter = new IntentFilter();

if (DEBUG_MEDIA_FAKE_ARTWORK) {

demoFilter.addAction(ACTION_FAKE_ARTWORK);

}

demoFilter.addAction(ACTION_DEMO);

context.registerReceiverAsUser(mDemoReceiver, UserHandle.ALL, demoFilter,

android.Manifest.permission.DUMP, null);

// listen for USER_SETUP_COMPLETE setting (per-user)

mDeviceProvisionedController.addCallback(mUserSetupObserver);

mUserSetupObserver.onUserSetupChanged();

// disable profiling bars, since they overlap and clutter the output on app windows

ThreadedRenderer.overrideProperty("disableProfileBars", "true");

// Private API call to make the shadows look better for Recents

ThreadedRenderer.overrideProperty("ambientRatio", String.valueOf(1.5f));

}

Android8.1系统源码中如何判断一个ServiceRecord对应的服务是运行状态

分类：Android, Java 阅读 (1,161) 已关闭评论

5月 282020

        if (r.app != null && r.app.thread != null) {
            // If service is currently running.
            return true;
        }

if (r.app != null && r.app.thread != null) {

// If service is currently running.

return true;

}

ActiveServices.bindServiceLocked代码分析

分类：Android, Java 阅读 (994) 已关闭评论

5月 282020

    int bindServiceLocked(IApplicationThread caller, IBinder token, Intent service,
            String resolvedType, final IServiceConnection connection, int flags,
            String callingPackage, final int userId) throws TransactionTooLargeException {
        if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "bindService: " + service
                + " type=" + resolvedType + " conn=" + connection.asBinder()
                + " flags=0x" + Integer.toHexString(flags));
        // 获取调用bindService的进程信息，如果进程信息不存在，则报异常。为什么会不存在？
        final ProcessRecord callerApp = mAm.getRecordForAppLocked(caller);
        if (callerApp == null) {
            throw new SecurityException(
                    "Unable to find app for caller " + caller
                    + " (pid=" + Binder.getCallingPid()
                    + ") when binding service " + service);
        }

        ActivityRecord activity = null;
        // 这个token对应的是ContextImpl中的getActivityToken()，如果在一个Service中bind其他的Service，这个token是不是就是null了？
        if (token != null) {
            // 在Activity栈中看是否有调用的Activity，如果没有，则返回
            activity = ActivityRecord.isInStackLocked(token);
            if (activity == null) {
                Slog.w(TAG, "Binding with unknown activity: " + token);
                return 0;
            }
        }

        int clientLabel = 0;
        PendingIntent clientIntent = null;
        final boolean isCallerSystem = callerApp.info.uid == Process.SYSTEM_UID;

        // 这里看不太懂
        if (isCallerSystem) {
            // Hacky kind of thing -- allow system stuff to tell us
            // what they are, so we can report this elsewhere for
            // others to know why certain services are running.
            service.setDefusable(true);
            clientIntent = service.getParcelableExtra(Intent.EXTRA_CLIENT_INTENT);
            if (clientIntent != null) {
                clientLabel = service.getIntExtra(Intent.EXTRA_CLIENT_LABEL, 0);
                if (clientLabel != 0) {
                    // There are no useful extras in the intent, trash them.
                    // System code calling with this stuff just needs to know
                    // this will happen.
                    service = service.cloneFilter();
                }
            }
        }

        // 把要绑定的服务看作一个Activity？后面还有相关的判断
        if ((flags&Context.BIND_TREAT_LIKE_ACTIVITY) != 0) {
            // 检查权限，如果没有权限会直接报异常结束函数
            mAm.enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,
                    "BIND_TREAT_LIKE_ACTIVITY");
        }

        // 如果要请求管理白名单，但又不是系统应用，则报异常
        if ((flags & Context.BIND_ALLOW_WHITELIST_MANAGEMENT) != 0 && !isCallerSystem) {
            throw new SecurityException(
                    "Non-system caller " + caller + " (pid=" + Binder.getCallingPid()
                    + ") set BIND_ALLOW_WHITELIST_MANAGEMENT when binding service " + service);
        }

        // 调用者在前台？
        final boolean callerFg = callerApp.setSchedGroup != ProcessList.SCHED_GROUP_BACKGROUND;
        final boolean isBindExternal = (flags & Context.BIND_EXTERNAL_SERVICE) != 0;

        //ServiceLookupResult包含一个ServiceRecord成员和一个权限字符串
        ServiceLookupResult res =
            retrieveServiceLocked(service, resolvedType, callingPackage, Binder.getCallingPid(),
                    Binder.getCallingUid(), userId, true, callerFg, isBindExternal);
        if (res == null) {
            return 0;
        }
        if (res.record == null) {
            return -1;
        }
        ServiceRecord s = res.record;

        boolean permissionsReviewRequired = false;

        // 是否需要让用户预览所需权限，这一段没仔细看
        // If permissions need a review before any of the app components can run,
        // we schedule binding to the service but do not start its process, then
        // we launch a review activity to which is passed a callback to invoke
        // when done to start the bound service's process to completing the binding.
        if (mAm.mPermissionReviewRequired) {
            if (mAm.getPackageManagerInternalLocked().isPermissionsReviewRequired(
                    s.packageName, s.userId)) {

                permissionsReviewRequired = true;

                // Show a permission review UI only for binding from a foreground app
                if (!callerFg) {
                    Slog.w(TAG, "u" + s.userId + " Binding to a service in package"
                            + s.packageName + " requires a permissions review");
                    return 0;
                }

                final ServiceRecord serviceRecord = s;
                final Intent serviceIntent = service;

                RemoteCallback callback = new RemoteCallback(
                        new RemoteCallback.OnResultListener() {
                    @Override
                    public void onResult(Bundle result) {
                        synchronized(mAm) {
                            final long identity = Binder.clearCallingIdentity();
                            try {
                                if (!mPendingServices.contains(serviceRecord)) {
                                    return;
                                }
                                // If there is still a pending record, then the service
                                // binding request is still valid, so hook them up. We
                                // proceed only if the caller cleared the review requirement
                                // otherwise we unbind because the user didn't approve.
                                if (!mAm.getPackageManagerInternalLocked()
                                        .isPermissionsReviewRequired(
                                                serviceRecord.packageName,
                                                serviceRecord.userId)) {
                                    try {
                                        bringUpServiceLocked(serviceRecord,
                                                serviceIntent.getFlags(),
                                                callerFg, false, false);
                                    } catch (RemoteException e) {
                                        /* ignore - local call */
                                    }
                                } else {
                                    unbindServiceLocked(connection);
                                }
                            } finally {
                                Binder.restoreCallingIdentity(identity);
                            }
                        }
                    }
                });

                final Intent intent = new Intent(Intent.ACTION_REVIEW_PERMISSIONS);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                        | Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
                intent.putExtra(Intent.EXTRA_PACKAGE_NAME, s.packageName);
                intent.putExtra(Intent.EXTRA_REMOTE_CALLBACK, callback);

                if (DEBUG_PERMISSIONS_REVIEW) {
                    Slog.i(TAG, "u" + s.userId + " Launching permission review for package "
                            + s.packageName);
                }

                mAm.mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mAm.mContext.startActivityAsUser(intent, new UserHandle(userId));
                    }
                });
            }
        }

        final long origId = Binder.clearCallingIdentity();

        try {
            // 检查这个服务是不是在要重启的列表（还有个这个列表？）里，如果是就移除
            if (unscheduleServiceRestartLocked(s, callerApp.info.uid, false)) {
                if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "BIND SERVICE WHILE RESTART PENDING: "
                        + s);
            }

            // 是否有自动创建标志
            if ((flags&Context.BIND_AUTO_CREATE) != 0) {
                s.lastActivity = SystemClock.uptimeMillis();
                // 如果已连接这个服务的连接都没有BIND_AUTO_CREATE标志
                if (!s.hasAutoCreateConnections()) {
                    // This is the first binding, let the tracker know.
                    ServiceState stracker = s.getTracker();
                    if (stracker != null) {
                        stracker.setBound(true, mAm.mProcessStats.getMemFactorLocked(),
                                s.lastActivity);
                    }
                }
            }

            // 和ActivityManagerService联系起来？
            mAm.startAssociationLocked(callerApp.uid, callerApp.processName, callerApp.curProcState,
                    s.appInfo.uid, s.name, s.processName);
            // Once the apps have become associated, if one of them is caller is ephemeral
            // the target app should now be able to see the calling app
            mAm.grantEphemeralAccessLocked(callerApp.userId, service,
                    s.appInfo.uid, UserHandle.getAppId(callerApp.uid));

            AppBindRecord b = s.retrieveAppBindingLocked(service, callerApp);
            ConnectionRecord c = new ConnectionRecord(b, activity,
                    connection, flags, clientLabel, clientIntent);

            IBinder binder = connection.asBinder();
            ArrayList<ConnectionRecord> clist = s.connections.get(binder);
            if (clist == null) {
                clist = new ArrayList<ConnectionRecord>();
                s.connections.put(binder, clist);
            }
            clist.add(c);
            b.connections.add(c);
            if (activity != null) {
                if (activity.connections == null) {
                    activity.connections = new HashSet<ConnectionRecord>();
                }
                activity.connections.add(c);
            }
            b.client.connections.add(c);
            if ((c.flags&Context.BIND_ABOVE_CLIENT) != 0) {
                b.client.hasAboveClient = true;
            }
            if ((c.flags&Context.BIND_ALLOW_WHITELIST_MANAGEMENT) != 0) {
                s.whitelistManager = true;
            }
            if (s.app != null) {
                updateServiceClientActivitiesLocked(s.app, c, true);
            }
            clist = mServiceConnections.get(binder);
            if (clist == null) {
                clist = new ArrayList<ConnectionRecord>();
                mServiceConnections.put(binder, clist);
            }
            clist.add(c);

            // bringUpServiceLocked这里是启动service的地方，调用路径bringUpServiceLocked->realStartServiceLocked->
            // app.thread.scheduleCreateService->ActivityThread.scheduleCreateService->ActivityThread.handleCreateService，如果启动成功则返回0
            if ((flags&Context.BIND_AUTO_CREATE) != 0) {
                s.lastActivity = SystemClock.uptimeMillis();
                if (bringUpServiceLocked(s, service.getFlags(), callerFg, false,
                        permissionsReviewRequired) != null) {
                    return 0;
                }
            }

            if (s.app != null) {
                if ((flags&Context.BIND_TREAT_LIKE_ACTIVITY) != 0) {
                    s.app.treatLikeActivity = true;
                }
                if (s.whitelistManager) {
                    s.app.whitelistManager = true;
                }
                // This could have made the service more important.
                mAm.updateLruProcessLocked(s.app, s.app.hasClientActivities
                        || s.app.treatLikeActivity, b.client);
                mAm.updateOomAdjLocked(s.app, true);
            }

            if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "Bind " + s + " with " + b
                    + ": received=" + b.intent.received
                    + " apps=" + b.intent.apps.size()
                    + " doRebind=" + b.intent.doRebind);

            if (s.app != null && b.intent.received) {
                // 如果服务已经运行，则立刻发布connection
                // Service is already running, so we can immediately
                // publish the connection.
                try {
                    c.conn.connected(s.name, b.intent.binder, false);
                } catch (Exception e) {
                    Slog.w(TAG, "Failure sending service " + s.shortName
                            + " to connection " + c.conn.asBinder()
                            + " (in " + c.binding.client.processName + ")", e);
                }

                // If this is the first app connected back to this binding,
                // and the service had previously asked to be told when
                // rebound, then do so.
                if (b.intent.apps.size() == 1 && b.intent.doRebind) {
                    requestServiceBindingLocked(s, b.intent, callerFg, true);
                }
            } else if (!b.intent.requested) {
                requestServiceBindingLocked(s, b.intent, callerFg, false);
            }

            getServiceMapLocked(s.userId).ensureNotStartingBackgroundLocked(s);

        } finally {
            Binder.restoreCallingIdentity(origId);
        }

        return 1;
    }

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int bindServiceLocked(IApplicationThread caller, IBinder token, Intent service,

String resolvedType, final IServiceConnection connection, int flags,

String callingPackage, final int userId) throws TransactionTooLargeException {

if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "bindService: " + service

+ " type=" + resolvedType + " conn=" + connection.asBinder()

+ " flags=0x" + Integer.toHexString(flags));

// 获取调用bindService的进程信息，如果进程信息不存在，则报异常。为什么会不存在？

final ProcessRecord callerApp = mAm.getRecordForAppLocked(caller);

if (callerApp == null) {

throw new SecurityException(

"Unable to find app for caller " + caller

+ " (pid=" + Binder.getCallingPid()

+ ") when binding service " + service);

}

ActivityRecord activity = null;

// 这个token对应的是ContextImpl中的getActivityToken()，如果在一个Service中bind其他的Service，这个token是不是就是null了？

if (token != null) {

// 在Activity栈中看是否有调用的Activity，如果没有，则返回

activity = ActivityRecord.isInStackLocked(token);

if (activity == null) {

Slog.w(TAG, "Binding with unknown activity: " + token);

return 0;

}

int clientLabel = 0;

PendingIntent clientIntent = null;

final boolean isCallerSystem = callerApp.info.uid == Process.SYSTEM_UID;

// 这里看不太懂

if (isCallerSystem) {

// Hacky kind of thing -- allow system stuff to tell us

// what they are, so we can report this elsewhere for

// others to know why certain services are running.

service.setDefusable(true);

clientIntent = service.getParcelableExtra(Intent.EXTRA_CLIENT_INTENT);

if (clientIntent != null) {

clientLabel = service.getIntExtra(Intent.EXTRA_CLIENT_LABEL, 0);

if (clientLabel != 0) {

// There are no useful extras in the intent, trash them.

// System code calling with this stuff just needs to know

// this will happen.

service = service.cloneFilter();

}

// 把要绑定的服务看作一个Activity？后面还有相关的判断

if ((flags&Context.BIND_TREAT_LIKE_ACTIVITY) != 0) {

// 检查权限，如果没有权限会直接报异常结束函数

mAm.enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,

"BIND_TREAT_LIKE_ACTIVITY");

}

// 如果要请求管理白名单，但又不是系统应用，则报异常

if ((flags & Context.BIND_ALLOW_WHITELIST_MANAGEMENT) != 0 && !isCallerSystem) {

throw new SecurityException(

"Non-system caller " + caller + " (pid=" + Binder.getCallingPid()

+ ") set BIND_ALLOW_WHITELIST_MANAGEMENT when binding service " + service);

}

// 调用者在前台？

final boolean callerFg = callerApp.setSchedGroup != ProcessList.SCHED_GROUP_BACKGROUND;

final boolean isBindExternal = (flags & Context.BIND_EXTERNAL_SERVICE) != 0;

//ServiceLookupResult包含一个ServiceRecord成员和一个权限字符串

ServiceLookupResult res =

retrieveServiceLocked(service, resolvedType, callingPackage, Binder.getCallingPid(),

Binder.getCallingUid(), userId, true, callerFg, isBindExternal);

if (res == null) {

return 0;

}

if (res.record == null) {

return -1;

}

ServiceRecord s = res.record;

boolean permissionsReviewRequired = false;

// 是否需要让用户预览所需权限，这一段没仔细看

// If permissions need a review before any of the app components can run,

// we schedule binding to the service but do not start its process, then

// we launch a review activity to which is passed a callback to invoke

// when done to start the bound service's process to completing the binding.

if (mAm.mPermissionReviewRequired) {

if (mAm.getPackageManagerInternalLocked().isPermissionsReviewRequired(

s.packageName, s.userId)) {

permissionsReviewRequired = true;

// Show a permission review UI only for binding from a foreground app

if (!callerFg) {

Slog.w(TAG, "u" + s.userId + " Binding to a service in package"

+ s.packageName + " requires a permissions review");

return 0;

}

final ServiceRecord serviceRecord = s;

final Intent serviceIntent = service;

RemoteCallback callback = new RemoteCallback(

new RemoteCallback.OnResultListener() {

@Override

public void onResult(Bundle result) {

synchronized(mAm) {

final long identity = Binder.clearCallingIdentity();

try {

if (!mPendingServices.contains(serviceRecord)) {

return;

}

// If there is still a pending record, then the service

// binding request is still valid, so hook them up. We

// proceed only if the caller cleared the review requirement

// otherwise we unbind because the user didn't approve.

if (!mAm.getPackageManagerInternalLocked()

.isPermissionsReviewRequired(

serviceRecord.packageName,

serviceRecord.userId)) {

try {

bringUpServiceLocked(serviceRecord,

serviceIntent.getFlags(),

callerFg, false, false);

} catch (RemoteException e) {

/* ignore - local call */

}

} else {

unbindServiceLocked(connection);

}

} finally {

Binder.restoreCallingIdentity(identity);

}

});

final Intent intent = new Intent(Intent.ACTION_REVIEW_PERMISSIONS);

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK

| Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);

intent.putExtra(Intent.EXTRA_PACKAGE_NAME, s.packageName);

intent.putExtra(Intent.EXTRA_REMOTE_CALLBACK, callback);

if (DEBUG_PERMISSIONS_REVIEW) {

Slog.i(TAG, "u" + s.userId + " Launching permission review for package "

+ s.packageName);

}

mAm.mHandler.post(new Runnable() {

@Override

public void run() {

mAm.mContext.startActivityAsUser(intent, new UserHandle(userId));

}

});

}

final long origId = Binder.clearCallingIdentity();

try {

// 检查这个服务是不是在要重启的列表（还有个这个列表？）里，如果是就移除

if (unscheduleServiceRestartLocked(s, callerApp.info.uid, false)) {

if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "BIND SERVICE WHILE RESTART PENDING: "

+ s);

}

// 是否有自动创建标志

if ((flags&Context.BIND_AUTO_CREATE) != 0) {

s.lastActivity = SystemClock.uptimeMillis();

// 如果已连接这个服务的连接都没有BIND_AUTO_CREATE标志

if (!s.hasAutoCreateConnections()) {

// This is the first binding, let the tracker know.

ServiceState stracker = s.getTracker();

if (stracker != null) {

stracker.setBound(true, mAm.mProcessStats.getMemFactorLocked(),

s.lastActivity);

}

// 和ActivityManagerService联系起来？

mAm.startAssociationLocked(callerApp.uid, callerApp.processName, callerApp.curProcState,

s.appInfo.uid, s.name, s.processName);

// Once the apps have become associated, if one of them is caller is ephemeral

// the target app should now be able to see the calling app

mAm.grantEphemeralAccessLocked(callerApp.userId, service,

s.appInfo.uid, UserHandle.getAppId(callerApp.uid));

AppBindRecord b = s.retrieveAppBindingLocked(service, callerApp);

ConnectionRecord c = new ConnectionRecord(b, activity,

connection, flags, clientLabel, clientIntent);

IBinder binder = connection.asBinder();

ArrayList<ConnectionRecord> clist = s.connections.get(binder);

if (clist == null) {

clist = new ArrayList<ConnectionRecord>();

s.connections.put(binder, clist);

}

clist.add(c);

b.connections.add(c);

if (activity != null) {

if (activity.connections == null) {

activity.connections = new HashSet<ConnectionRecord>();

}

activity.connections.add(c);

}

b.client.connections.add(c);

if ((c.flags&Context.BIND_ABOVE_CLIENT) != 0) {

b.client.hasAboveClient = true;

}

if ((c.flags&Context.BIND_ALLOW_WHITELIST_MANAGEMENT) != 0) {

s.whitelistManager = true;

}

if (s.app != null) {

updateServiceClientActivitiesLocked(s.app, c, true);

}

clist = mServiceConnections.get(binder);

if (clist == null) {

clist = new ArrayList<ConnectionRecord>();

mServiceConnections.put(binder, clist);

}

clist.add(c);

// bringUpServiceLocked这里是启动service的地方，调用路径bringUpServiceLocked->realStartServiceLocked->

// app.thread.scheduleCreateService->ActivityThread.scheduleCreateService->ActivityThread.handleCreateService，如果启动成功则返回0

if ((flags&Context.BIND_AUTO_CREATE) != 0) {

s.lastActivity = SystemClock.uptimeMillis();

if (bringUpServiceLocked(s, service.getFlags(), callerFg, false,

permissionsReviewRequired) != null) {

return 0;

}

if (s.app != null) {

if ((flags&Context.BIND_TREAT_LIKE_ACTIVITY) != 0) {

s.app.treatLikeActivity = true;

}

if (s.whitelistManager) {

s.app.whitelistManager = true;

}

// This could have made the service more important.

mAm.updateLruProcessLocked(s.app, s.app.hasClientActivities

|| s.app.treatLikeActivity, b.client);

mAm.updateOomAdjLocked(s.app, true);

}

if (DEBUG_SERVICE) Slog.v(TAG_SERVICE, "Bind " + s + " with " + b

+ ": received=" + b.intent.received

+ " apps=" + b.intent.apps.size()

+ " doRebind=" + b.intent.doRebind);

if (s.app != null && b.intent.received) {

// 如果服务已经运行，则立刻发布connection

// Service is already running, so we can immediately

// publish the connection.

try {

c.conn.connected(s.name, b.intent.binder, false);

} catch (Exception e) {

Slog.w(TAG, "Failure sending service " + s.shortName

+ " to connection " + c.conn.asBinder()

+ " (in " + c.binding.client.processName + ")", e);

}

// If this is the first app connected back to this binding,

// and the service had previously asked to be told when

// rebound, then do so.

if (b.intent.apps.size() == 1 && b.intent.doRebind) {

requestServiceBindingLocked(s, b.intent, callerFg, true);

}

} else if (!b.intent.requested) {

requestServiceBindingLocked(s, b.intent, callerFg, false);

}

getServiceMapLocked(s.userId).ensureNotStartingBackgroundLocked(s);

} finally {

Binder.restoreCallingIdentity(origId);

}

return 1;

}

TextView点击事件分发流程

分类：Android, Java 阅读 (931) 已关闭评论

5月 262020

本文基于Android8.1系统源码分析

本文以TextView为例描述一下，点击事件的分发流程

如下图：

Android8.1去除user模式下允许usb设备连接提示框

分类：Android, Java 阅读 (1,919) 已关闭评论

5月 262020

去除下图所示提示框：

修改文件：frameworks/base/services/usb/java/com/android/server/usb/UsbDebuggingManager.java

增加import头

import android.os.IBinder;
import android.os.ServiceManager;
import android.util.Log;
import android.hardware.usb.IUsbManager;
import android.hardware.usb.UsbManager;

import android.os.IBinder;

import android.os.ServiceManager;

import android.util.Log;

import android.hardware.usb.IUsbManager;

import android.hardware.usb.UsbManager;

在处理MESSAGE_ADB_CONFIRM消息那一段，把startConfirmation(key, mFingerprints);去掉，改成如下代码

                case MESSAGE_ADB_CONFIRM: {
                    if ("trigger_restart_min_framework".equals(
                            SystemProperties.get("vold.decrypt"))) {
                        Slog.d(TAG, "Deferring adb confirmation until after vold decrypt");
                        if (mThread != null) {
                            mThread.sendResponse("NO");
                        }
                        break;
                    }
                    String key = (String)msg.obj;
                    String fingerprints = getFingerprints(key);
                    if ("".equals(fingerprints)) {
                        if (mThread != null) {
                            mThread.sendResponse("NO");
                        }
                        break;
                    }

                    try {
                        IBinder b = ServiceManager.getService(Context.USB_SERVICE);
                        IUsbManager service = IUsbManager.Stub.asInterface(b);
                        service.allowUsbDebugging(true, key);
                    } catch (Exception e) {
                        Log.e(TAG, "Unable to notify Usb service", e);
                    }
        
                    mFingerprints = fingerprints;
                    //去掉startConfirmation函数
                    //startConfirmation(key, mFingerprints);
                    break;
                }

case MESSAGE_ADB_CONFIRM: {

if ("trigger_restart_min_framework".equals(

SystemProperties.get("vold.decrypt"))) {

Slog.d(TAG, "Deferring adb confirmation until after vold decrypt");

if (mThread != null) {

mThread.sendResponse("NO");

}

break;

}

String key = (String)msg.obj;

String fingerprints = getFingerprints(key);

if ("".equals(fingerprints)) {

if (mThread != null) {

mThread.sendResponse("NO");

}

break;

}

try {

IBinder b = ServiceManager.getService(Context.USB_SERVICE);

IUsbManager service = IUsbManager.Stub.asInterface(b);

service.allowUsbDebugging(true, key);

} catch (Exception e) {

Log.e(TAG, "Unable to notify Usb service", e);

}

mFingerprints = fingerprints;

//去掉startConfirmation函数

//startConfirmation(key, mFingerprints);

break;

}

Android组件绘制流程

分类：Android, Java 阅读 (748) 已关闭评论

5月 212020

首先是在ViewRootImpl.java中的performTraversals中开始的？

最主要的有三个子函数

performMeasure、performLayout、performDraw

这三个函数分别对应View中的onMeasure、onLayout、onDraw

onMeasure是为了计算view的宽度和高度

最后使用setMeasuredDimension设置view的宽度和高度

onLayout是为了给子组件设置尺寸和位置(如果组件是个容器？)

onDraw是具体的窗体绘制函数

Choreographer学习记录

分类：Android, Java 阅读 (993) 已关闭评论

5月 202020

一、官方介绍

Choreographer是用于协调动画、输入和绘图的时间的。

Choreographer从显示子系统接收时间脉冲（比如垂直同步），然后安排下一个显示帧渲染工作。

应用通常通过动画框架和视图层次结构的高级抽象方法与choreographer进行交互。下面是一些可以通过高级api可以做的操作：

使用android.animation.ValueAnimator#start

未完……

二、Choreographer可以协调的操作类型

1. CALLBACK_INPUT = 0

输入回调，最先执行的，优先级比较高

2. CALLBACK_ANIMATION = 1

动画回调，在traversals之前运行

3. CALLBACK_TRAVERSAL = 2;

遍历回调，处理layout和draw，在所有的异步信息处理之后运行。

4. CALLBACK_COMMIT = 3;

处理frame的post-draw操作。在traversal操作完成后运行。

三、Choreographer是如何管理各种回调的

是由一个CallbackRecord组成的链表来记录要执行的各种回调的

是由一个CallbackQueue数组来管理这些链表的（添加、删除），每一种回调类型一个CallbackQueue

mHead是第一个CallbackRecord，执行时间最近的一个

为什么要重新写一个CallbackQueue？

因为这个队列使用的很频繁，所以自己封装一个轻量级的Queue

四、Choreographer是如何与上层Api交互的

如上图：上层框架创建Choreographer的实例，并循环进行调用

五、mCallbackPool对象的使用（性能优化）

    private CallbackRecord obtainCallbackLocked(long dueTime, Object action, Object token) {
        CallbackRecord callback = mCallbackPool;
        if (callback == null) {
            callback = new CallbackRecord();
        } else {
            mCallbackPool = callback.next;
            callback.next = null;
        }
        callback.dueTime = dueTime;
        callback.action = action;
        callback.token = token;
        return callback;
    }

    private void recycleCallbackLocked(CallbackRecord callback) {
        callback.action = null;
        callback.token = null;
        callback.next = mCallbackPool;
        mCallbackPool = callback;
    }

private CallbackRecord obtainCallbackLocked(long dueTime, Object action, Object token) {

CallbackRecord callback = mCallbackPool;

if (callback == null) {

callback = new CallbackRecord();

} else {

mCallbackPool = callback.next;

callback.next = null;

}

callback.dueTime = dueTime;

callback.action = action;

callback.token = token;

return callback;

}

private void recycleCallbackLocked(CallbackRecord callback) {

callback.action = null;

callback.token = null;

callback.next = mCallbackPool;

mCallbackPool = callback;

}

其中obtainCallbackLocked是用于试图新建一个CallbackRecord，recycleCallbackLocked是用于回收一个CallbackRecord

重复利用mCallbackPool，尽量避免重复创建CallbackRecord

六、为什么不用Handler管理？

因为它还有自己其他的业务逻辑，比如CallbackQueue。

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