本文共 19533 字,大约阅读时间需要 65 分钟。
上一篇文章详细介绍了开关机动画的显示过程,Android系统开机时,在启动SurfaceFlinger服务过程中通过Android属性系统方式来启动bootanim进程,实现开机动画显示过程;当系统关机时,又是如何启动关机动画的呢?Android系统的整个关机流程又是怎样的呢?本文就针对这两个问题透过源码来给出具体的分析。我们知道,当长按电源键,系统会弹出关机提示对话框
当点击选择关机时,系统就会完成整个关机流程。接下来就通过源码来介绍Android关机流程的完整实现过程。当长按电源键时,按键消息被分发到PhoneWindowManager的interceptKeyBeforeQueueing函数中处理:
- public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags, boolean isScreenOn) {
- ...
- switch (keyCode) {
- ...
- case KeyEvent.KEYCODE_POWER: {
- result &= ~ACTION_PASS_TO_USER;
- if (down) {
- if (isScreenOn && !mPowerKeyTriggered
- && (event.getFlags() & KeyEvent.FLAG_FALLBACK) == 0) {
- mPowerKeyTriggered = true;
- mPowerKeyTime = event.getDownTime();
- interceptScreenshotChord();
- }
- ITelephony telephonyService = getTelephonyService();
- boolean hungUp = false;
- if (telephonyService != null) {
- try {
- if (telephonyService.isRinging()) {
-
- telephonyService.silenceRinger();
- } else if ((mIncallPowerBehavior
- & Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR_HANGUP) != 0
- && telephonyService.isOffhook()) {
-
-
- hungUp = telephonyService.endCall();
- }
- } catch (RemoteException ex) {
- Log.w(TAG, "ITelephony threw RemoteException", ex);
- }
- }
- interceptPowerKeyDown(!isScreenOn || hungUp
- || mVolumeDownKeyTriggered || mVolumeUpKeyTriggered);
- } else {
- ...
- }
- break;
- }
- ...
- }
- return result;
- }
电源键和音量键的组合可以实现特定功能,比如按下电源键和音量向下键,可实现抓屏,interceptKeyBeforeQueueing函数首先根据条件处理电源键按下的特定任务,然后调用interceptPowerKeyDown做进一步处理
- private void interceptPowerKeyDown(boolean handled) {
- mPowerKeyHandled = handled;
- if (!handled) {
-
- mHandler.postDelayed(mPowerLongPress, ViewConfiguration.getGlobalActionKeyTimeout());
- }
- }
这里的mHandler是在初始化PhoneWindowManager对象时创建的
- public void init(Context context, IWindowManager windowManager,WindowManagerFuncs windowManagerFuncs,
- LocalPowerManager powerManager) {
- ...
- mHandler = new PolicyHandler();
- ...
- }
将一个Runnable对象mPowerLongPress发送到PolicyHandler中进行处理
- private final Runnable mPowerLongPress = new Runnable() {
- public void run() {
-
- if (mLongPressOnPowerBehavior < 0) {
- mLongPressOnPowerBehavior = mContext.getResources().getInteger(
- com.android.internal.R.integer.config_longPressOnPowerBehavior);
- }
- switch (mLongPressOnPowerBehavior) {
- case LONG_PRESS_POWER_NOTHING:
- break;
- case LONG_PRESS_POWER_GLOBAL_ACTIONS:
- mPowerKeyHandled = true;
- performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
- sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
- showGlobalActionsDialog();
- break;
- case LONG_PRESS_POWER_SHUT_OFF:
- mPowerKeyHandled = true;
- performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
- sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
- mWindowManagerFuncs.shutdown();
- break;
- }
- }
- };
在处理电源长按事件时,根据mLongPressOnPowerBehavior完成不同的处理过程,mLongPressOnPowerBehavior的值是通过配置文件来设置的,在frameworks/base/core/res/values/config.xml中有以下一段配置:
通过读取配置文件取得config_longPressOnPowerBehavior配置的值为1,因此将显示关机对话框
- case LONG_PRESS_POWER_GLOBAL_ACTIONS:
- mPowerKeyHandled = true;
- performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
-
- sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
-
- showGlobalActionsDialog();
- break;
关机对话框显示:
- void showGlobalActionsDialog() {
-
- if (mGlobalActions == null) {
- mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);
- }
- final boolean keyguardShowing = keyguardIsShowingTq();
-
- mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());
- if (keyguardShowing) {
-
-
- mKeyguardMediator.pokeWakelock();
- }
- }
通过GlobalActions的showDialog函数来显示对话框
- public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
- mKeyguardShowing = keyguardShowing;
- mDeviceProvisioned = isDeviceProvisioned;
- if (mDialog != null) {
- mDialog.dismiss();
- mDialog = null;
-
- mHandler.sendEmptyMessage(MESSAGE_SHOW);
- } else {
- handleShow();
- }
- }
- private void handleShow() {
-
- mDialog = createDialog();
- prepareDialog();
- mDialog.show();
- mDialog.getWindow().getDecorView().setSystemUiVisibility(View.STATUS_BAR_DISABLE_EXPAND);
- }
createDialog()函数用于创建一个即将显示的关机对话框,就是前面图片显示的对话框。
- private AlertDialog createDialog() {
-
-
-
- if (!mHasVibrator) {
- mSilentModeAction = new SilentModeToggleAction();
- } else {
- mSilentModeAction = new SilentModeTriStateAction(mContext, mAudioManager, mHandler);
- }
-
- mAirplaneModeOn = new ToggleAction(
- R.drawable.ic_lock_airplane_mode,
- R.drawable.ic_lock_airplane_mode_off,
- R.string.global_actions_toggle_airplane_mode,
- R.string.global_actions_airplane_mode_on_status,
- R.string.global_actions_airplane_mode_off_status) {
- void onToggle(boolean on) {
- if (mHasTelephony && Boolean.parseBoolean(SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE))) {
- mIsWaitingForEcmExit = true;
-
- Intent ecmDialogIntent =new Intent(TelephonyIntents.ACTION_SHOW_NOTICE_ECM_BLOCK_OTHERS, null);
- ecmDialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
- mContext.startActivity(ecmDialogIntent);
- } else {
- changeAirplaneModeSystemSetting(on);
- mHandler.removeMessages(EVENT_SERVICE_CHANGE_WAIT_TIMEOUT);
- mHandler.sendEmptyMessageDelayed(EVENT_SERVICE_CHANGE_WAIT_TIMEOUT,DELAY_AIRPLANE_SET_TIME);
- }
- }
- @Override
- protected void changeStateFromPress(boolean buttonOn) {
- if (!mHasTelephony) return;
-
- if (!(Boolean.parseBoolean(SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE)))) {
- mState = buttonOn ? State.TurningOn : State.TurningOff;
- mAirplaneState = mState;
- }
- }
- public boolean showDuringKeyguard() {
- return true;
- }
- public boolean showBeforeProvisioning() {
- return false;
- }
- };
-
- onAirplaneModeChanged();
- onRadioBusyStateChanged();
- mItems = new ArrayList<Action>();
-
-
- mItems.add(
-
- new SinglePressAction(com.android.internal.R.drawable.ic_lock_power_off,
- R.string.global_action_power_off) {
- public void onPress() {
-
- mWindowManagerFuncs.shutdown();
- }
- public boolean onLongPress() {
- mWindowManagerFuncs.rebootSafeMode();
- return true;
- }
- public boolean showDuringKeyguard() {
- return true;
- }
- public boolean showBeforeProvisioning() {
- return true;
- }
- });
-
- mItems.add(mAirplaneModeOn);
-
- if (SHOW_SILENT_TOGGLE) {
- mItems.add(mSilentModeAction);
- }
-
- List<UserInfo> users = mContext.getPackageManager().getUsers();
- if (users.size() > 1) {
- UserInfo currentUser;
- try {
- currentUser = ActivityManagerNative.getDefault().getCurrentUser();
- } catch (RemoteException re) {
- currentUser = null;
- }
- for (final UserInfo user : users) {
- boolean isCurrentUser = currentUser == null
- ? user.id == 0 : (currentUser.id == user.id);
- SinglePressAction switchToUser = new SinglePressAction(
- com.android.internal.R.drawable.ic_menu_cc,
- (user.name != null ? user.name : "Primary")
- + (isCurrentUser ? " \u2714" : "")) {
- public void onPress() {
- try {
- ActivityManagerNative.getDefault().switchUser(user.id);
- getWindowManager().lockNow();
- } catch (RemoteException re) {
- Log.e(TAG, "Couldn't switch user " + re);
- }
- }
-
- public boolean showDuringKeyguard() {
- return true;
- }
-
- public boolean showBeforeProvisioning() {
- return false;
- }
- };
- mItems.add(switchToUser);
- }
- }
- mAdapter = new MyAdapter();
-
- final AlertDialog.Builder ab = new AlertDialog.Builder(mContext);
- ab.setAdapter(mAdapter, this).setInverseBackgroundForced(true);
- final AlertDialog dialog = ab.create();
- dialog.getListView().setItemsCanFocus(true);
- dialog.getListView().setLongClickable(true);
- dialog.getListView().setOnItemLongClickListener(
- new AdapterView.OnItemLongClickListener() {
- @Override
- public boolean onItemLongClick(AdapterView<?> parent, View view, int position,
- long id) {
- return mAdapter.getItem(position).onLongPress();
- }
- });
- dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG);
- dialog.setOnDismissListener(this);
- return dialog;
- }
这里需要介绍对话框列表创建的方法,代码实现比较灵魂,值得学习。首先将显示对话框列表中的每一项用应该Action来描述,Action是一个接口,定义了每一个列表项的动作方法
各个列表项定义不同类型的Action,比如关机选项使用SinglePressAction来描述,目前Android系统定义了几种类型的Action,对应关机对话框中的不同选项。
将创建的列表选项添加到动态数组mItems中,并且为该对话框定义一个适配器MyAdapter,在单击对话框列表项时,调用适配器中对应的项来响应单击事件。Android适配器的使用实现了MVC编程模式,将数据和视图分开。通常我们将数据保存在一个数组中,通过适配器和视图控件关联显示,只不过这里的数据比较特殊,它是用来描述列表项显示的内容。
- public boolean onItemLongClick(AdapterView<?> parent, View view, int position,long id) {
- return mAdapter.getItem(position).onLongPress();
- }
-
- public void onClick(DialogInterface dialog, int which) {
- if (!(mAdapter.getItem(which) instanceof SilentModeTriStateAction)) {
- dialog.dismiss();
- }
- mAdapter.getItem(which).onPress();
- }
对于关机选项,其单击和长按事件处理过程如下:
- public void onPress() {
-
- mWindowManagerFuncs.shutdown();
- }
-
- public boolean onLongPress() {
- mWindowManagerFuncs.rebootSafeMode();
- return true;
- }
对关机的处理都是调用mWindowManagerFuncs来完成的,mWindowManagerFuncs的类型为WindowManagerFuncs,在调用PhoneWindowManager的init函数时通过参数传进来。mWindowManagerFuncs对象在那里构造呢?WindowManagerService定义了一个WindowManagerPolicy类型变量:
- final WindowManagerPolicy mPolicy = PolicyManager.makeNewWindowManager();
通过策略管理类PolicyManager对象的makeNewWindowManager函数创建一个窗口策略管理对象
- public static WindowManagerPolicy makeNewWindowManager() {
- return sPolicy.makeNewWindowManager();
- }
该函数通过Binder通信方式请求服务端Policy来完成对象的创建过程
Policy.java
- public WindowManagerPolicy makeNewWindowManager() {
- return new PhoneWindowManager();
- }
在WindowManagerService的构造过程中,会创建一个PolicyThread类来初始化窗口管理策略WindowManagerPolicy
- private WindowManagerService(Context context, PowerManagerService pm,
- boolean haveInputMethods, boolean showBootMsgs, boolean onlyCore) {
- ...
- PolicyThread thr = new PolicyThread(mPolicy, this, context, pm);
- thr.start();
- synchronized (thr) {
- while (!thr.mRunning) {
- try {
- thr.wait();
- } catch (InterruptedException e) {
- }
- }
- }
- ...
- }
在PolicyThread线程中执行初始化函数
- static class PolicyThread extends Thread {
- @Override
- public void run() {
- Looper.prepare();
- ...
- mPolicy.init(mContext, mService, mService, mPM);
- synchronized (this) {
- mRunning = true;
- notifyAll();
- }
- ...
- Looper.loop();
- }
- }
mPolicy的类型定义为WindowManagerPolicy类型,而WindowManagerPolicy是一个接口类型,PhoneWindowManager实现了该接口,为mPolicy创建的真正对象是PhoneWindowManager对象,因此PolicyThread线程将调用PhoneWindowManager的init函数 - public void init(Context context, IWindowManager windowManager,
- WindowManagerFuncs windowManagerFuncs,LocalPowerManager powerManager) {
- ...
- mWindowManagerFuncs = windowManagerFuncs;
- ...
- }
传进来的参数windowManager和windowManagerFuncs都是WindowManagerService对象,因为WindowManagerService继承于IWindowManager.Stub类同时实现了WindowManagerPolicy.WindowManagerFuncs接口,这下就很清晰地知道GlobalActions类中的mWindowManagerFuncs变量其实是WindowManagerService对象,因此关机的单击及长按事件由WindowManagerService实现:
- public void shutdown() {
- ShutdownThread.shutdown(mContext, true);
- }
-
- public void rebootSafeMode() {
- ShutdownThread.rebootSafeMode(mContext, true);
- }
WindowManagerService也不真正实现关机操作,而是转交个ShutdownThread来完成。对于关机处理过程:
- public static void shutdown(final Context context, boolean confirm) {
- mReboot = false;
- mRebootSafeMode = false;
- shutdownInner(context, confirm);
- }
该函数实现非常简单,只是设置一些标志位,然后将关机任务又转交给shutdownInner来处理,这里的参数confirm用于标识是否需要弹出关机确认对话框。
- static void shutdownInner(final Context context, boolean confirm) {
-
-
- synchronized (sIsStartedGuard) {
- if (sIsStarted) {
- Log.d(TAG, "Request to shutdown already running, returning.");
- return;
- }
- }
- final int longPressBehavior = context.getResources().getInteger(
- com.android.internal.R.integer.config_longPressOnPowerBehavior);
- final int resourceId = mRebootSafeMode
- ? com.android.internal.R.string.reboot_safemode_confirm
- : (longPressBehavior == 2
- ? com.android.internal.R.string.shutdown_confirm_question
- : com.android.internal.R.string.shutdown_confirm);
- Log.d(TAG, "Notifying thread to start shutdown longPressBehavior=" + longPressBehavior);
-
- if (confirm) {
- final CloseDialogReceiver closer = new CloseDialogReceiver(context);
- final AlertDialog dialog = new AlertDialog.Builder(context)
- .setTitle(mRebootSafeMode
- ? com.android.internal.R.string.reboot_safemode_title
- : com.android.internal.R.string.power_off)
- .setMessage(resourceId)
- .setPositiveButton(com.android.internal.R.string.yes, new DialogInterface.OnClickListener() {
- public void onClick(DialogInterface dialog, int which) {
- beginShutdownSequence(context);
- }
- })
- .setNegativeButton(com.android.internal.R.string.no, null)
- .create();
- closer.dialog = dialog;
- dialog.setOnDismissListener(closer);
- dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
- dialog.show();
- } else {
- beginShutdownSequence(context);
- }
- }
调用beginShutdownSequence函数进入关机流程。
- private static void beginShutdownSequence(Context context) {
- synchronized (sIsStartedGuard) {
- if (sIsStarted) {
- Log.d(TAG, "Shutdown sequence already running, returning.");
- return;
- }
- sIsStarted = true;
- }
-
-
- ProgressDialog pd = new ProgressDialog(context);
- pd.setTitle(context.getText(com.android.internal.R.string.power_off));
- pd.setMessage(context.getText(com.android.internal.R.string.shutdown_progress));
- pd.setIndeterminate(true);
- pd.setCancelable(false);
- pd.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
-
- shutdownTime = SystemClock.elapsedRealtime() + MAX_SHUTDOWN_TIME;
-
- String[] bootcmd = { "bootanimation", "shutdown"} ;
- try {
- Log.i(TAG, "exec the bootanimation ");
- SystemProperties.set("service.bootanim.exit", "0");
- Runtime.getRuntime().exec(bootcmd);
- } catch (Exception e){
- Log.e(TAG,"bootanimation command exe err!");
- }
-
- sInstance.mContext = context;
- sInstance.mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
-
- sInstance.mCpuWakeLock = null;
- try {
- sInstance.mCpuWakeLock = sInstance.mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG + "-cpu");
- sInstance.mCpuWakeLock.setReferenceCounted(false);
- sInstance.mCpuWakeLock.acquire();
- } catch (SecurityException e) {
- Log.w(TAG, "No permission to acquire wake lock", e);
- sInstance.mCpuWakeLock = null;
- }
-
- sInstance.mScreenWakeLock = null;
- if (sInstance.mPowerManager.isScreenOn()) {
- try {
- sInstance.mScreenWakeLock = sInstance.mPowerManager.newWakeLock(
- PowerManager.FULL_WAKE_LOCK, TAG + "-screen");
- sInstance.mScreenWakeLock.setReferenceCounted(false);
- sInstance.mScreenWakeLock.acquire();
- } catch (SecurityException e) {
- Log.w(TAG, "No permission to acquire wake lock", e);
- sInstance.mScreenWakeLock = null;
- }
- }
-
- sInstance.mHandler = new Handler() {
- };
-
- sInstance.start();
- }
这个函数执行两个任务,1)通过虚拟机Runtime启动关机动画进程bootanimation,用于显示关机动画,开关机动画在 进行了详细的分析介绍。2)启动关机线程ShutdownThread来完成关机操作
- public void run() {
- BroadcastReceiver br = new BroadcastReceiver() {
- @Override public void onReceive(Context context, Intent intent) {
-
- actionDone();
- }
- };
-
- {
- String reason = (mReboot ? "1" : "0") + (mRebootReason != null ? mRebootReason : "");
- SystemProperties.set(SHUTDOWN_ACTION_PROPERTY, reason);
- }
-
- if (mRebootSafeMode) {
- SystemProperties.set(REBOOT_SAFEMODE_PROPERTY, "1");
- }
- Log.i(TAG, "Sending shutdown broadcast...");
-
- mActionDone = false;
-
- mContext.sendOrderedBroadcast(new Intent(Intent.ACTION_SHUTDOWN), null,
- br, mHandler, 0, null, null);
-
- final long endTime = SystemClock.elapsedRealtime() + MAX_BROADCAST_TIME;
- synchronized (mActionDoneSync) {
- while (!mActionDone) {
- long delay = endTime - SystemClock.elapsedRealtime();
- if (delay <= 0) {
- Log.w(TAG, "Shutdown broadcast timed out");
- break;
- }
- try {
- mActionDoneSync.wait(delay);
- } catch (InterruptedException e) {
- }
- }
- }
-
- final IActivityManager am =ActivityManagerNative.asInterface(ServiceManager.checkService("activity"));
- if (am != null) {
- try {
- am.shutdown(MAX_BROADCAST_TIME);
- } catch (RemoteException e) {
- }
- }
-
- shutdownRadios(MAX_RADIO_WAIT_TIME);
-
- shutdownIccs(MAX_ICC_WAIT_TIME);
-
- IMountShutdownObserver observer = new IMountShutdownObserver.Stub() {
- public void onShutDownComplete(int statusCode) throws RemoteException {
- Log.w(TAG, "Result code " + statusCode + " from MountService.shutdown");
- actionDone();
- }
- };
- Log.i(TAG, "Shutting down MountService");
-
- mActionDone = false;
- final long endShutTime = SystemClock.elapsedRealtime() + MAX_SHUTDOWN_WAIT_TIME;
- synchronized (mActionDoneSync) {
- try {
- final IMountService mount = IMountService.Stub.asInterface(ServiceManager.checkService("mount"));
- if (mount != null) {
- mount.shutdown(observer);
- } else {
- Log.w(TAG, "MountService unavailable for shutdown");
- }
- } catch (Exception e) {
- Log.e(TAG, "Exception during MountService shutdown", e);
- }
- while (!mActionDone) {
- long delay = endShutTime - SystemClock.elapsedRealtime();
- if (delay <= 0) {
- Log.w(TAG, "Shutdown wait timed out");
- break;
- }
- try {
- mActionDoneSync.wait(delay);
- } catch (InterruptedException e) {
- }
- }
- }
-
- long shutdownDelay = shutdownTime - SystemClock.elapsedRealtime();
- if (shutdownDelay > 0) {
- Log.i(TAG, "Shutdown delay:"+shutdownDelay);
- SystemClock.sleep(shutdownDelay);
- }
-
- rebootOrShutdown(mReboot, mRebootReason);
- }
该函数内主要完成以下一些工作:
(1)发送关机广播ACTION_SHUTDOWN
(2)关闭ActivityManager 服务
(3)关闭无线相关的服务
(4)关闭Iccs
(5)关闭MountService服务
- public static void rebootOrShutdown(boolean reboot, String reason) {
- if (reboot) {
- Log.i(TAG, "Rebooting, reason: " + reason);
- try {
- PowerManagerService.lowLevelReboot(reason);
- } catch (Exception e) {
- Log.e(TAG, "Reboot failed, will attempt shutdown instead", e);
- }
- } else if (SHUTDOWN_VIBRATE_MS > 0) {
-
- Vibrator vibrator = new SystemVibrator();
- try {
-
- vibrator.vibrate(SHUTDOWN_VIBRATE_MS);
- } catch (Exception e) {
-
- Log.w(TAG, "Failed to vibrate during shutdown.", e);
- }
-
- try {
- Thread.sleep(SHUTDOWN_VIBRATE_MS);
- } catch (InterruptedException unused) {
- }
- }
-
- Log.i(TAG, "Performing low-level shutdown...");
- PowerManagerService.lowLevelShutdown();
- }
这里是启动关机震动并关闭电源
- public static void lowLevelShutdown() {
- nativeShutdown();
- }
这里通过JNI调用C++的关机函数
- static void nativeShutdown(JNIEnv *env, jobject clazz) {
- delFlag();
- android_reboot(ANDROID_RB_POWEROFF, 0, 0);
- }
android_reboot函数最终通过Linux系统调用关闭系统。到此关机操作就基本完成了。