Android 4.1.2系统添加重启功能

对于Android的的手机或者平板长期使用，感觉会出现慢的情况，所以偶尔还是需要重启一下，而长按电源键弹出的菜单又没有重启选项，所以特在此记录自己添加这个功能的过程。
首先关机的那个弹出菜单是在frameworks/base/policy/src/com/android/internal/policy/impl/GlobalActions.java这个文件中创建的：

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 /**
  * Create the global actions dialog.
  * @return A new dialog.
  */
 private GlobalActionsDialog createDialog() {
     // Simple toggle style if there's no vibrator, otherwise use a tri-state
     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;
                 // Launch ECM exit dialog
                 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);
             }
         }

         @Override
         protected void changeStateFromPress(boolean buttonOn) {
             if (!mHasTelephony) return;

             // In ECM mode airplane state cannot be changed
             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();

     mItems = new ArrayList<Action>();

     // first: power off
     mItems.add(
         new SinglePressAction(
                 com.android.internal.R.drawable.ic_lock_power_off,
                 R.string.global_action_power_off) {

             public void onPress() {
                 // shutdown by making sure radio and power are handled accordingly.
                 mWindowManagerFuncs.shutdown(true);
             }

             public boolean onLongPress() {
                 mWindowManagerFuncs.rebootSafeMode(true);
                 return true;
             }

             public boolean showDuringKeyguard() {
                 return true;
             }

             public boolean showBeforeProvisioning() {
                 return true;
             }
         });

我们可以看到mItems.add函数是添加一个选项，该菜单的第一个选项就是关机选项，我们可以在此之后添加重启选项，代码如下：

 mItems.add(
     new SinglePressAction(
         com.android.internal.R.drawable.ic_lock_power_off,
         R.string.global_action_reboot) {

         public void onPress() {
             // reboot
             mWindowManagerFuncs.reboot();
         }

         public boolean showDuringKeyguard() {
             return true;
         }

         public boolean showBeforeProvisioning() {
             return true;
         }
     });

上面的代码中使用了mWindowManagerFuncs.reboot函数和R.string.global_action_reboot资源，因此我们需要该资源并实现reboot函数。
首先在frameworks/base/core/java/android/view/WindowManagerPolicy.java中添加reboot接口：

 /**
  * Interface for calling back in to the window manager that is private
  * between it and the policy.
  */
 public interface WindowManagerFuncs {

     ...

     /**
      * Switch the keyboard layout for the given device.
      * Direction should be +1 or -1 to go to the next or previous keyboard layout.
      */
     public void switchKeyboardLayout(int deviceId, int direction);

     public void shutdown();
     public void reboot();
     public void rebootSafeMode();
 }

然后在frameworks/base/services/java/com/android/server/wm/WindowManagerService.java中实现该接口：

 // Called by window manager policy. Not exposed externally.
 @Override
 public void shutdown() {
     ShutdownThread.shutdown(mContext, true);
 }

 // Called by window manager policy. Not exposed externally.
 @Override
 public void reboot() {
     ShutdownThread.reboot(mContext, null, true);
 }

 // Called by window manager policy. Not exposed externally.
 @Override
 public void rebootSafeMode() {
     ShutdownThread.rebootSafeMode(mContext, true);
 }

接下来，为了在按下重启选项之后，能出现”重启“之类的提示，还需要修改frameworks/base/services/java/com/android/server/pm/ShutdownThread.java中的shutdownInner函数和beginShutdownSequence函数：

 static void shutdownInner(final Context context, boolean confirm) {
     // ensure that only one thread is trying to power down.
     // any additional calls are just returned
     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
                     : (mReboot ? com.android.internal.R.string.reboot_confirm :
                         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
                         : (mReboot ? com.android.internal.R.string.reboot :
                             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);
     }
 }

 private static void beginShutdownSequence(Context context) {
    synchronized (sIsStartedGuard) {
        if (sIsStarted) {
            Log.d(TAG, "Shutdown sequence already running, returning.");
            return;
        }
        sIsStarted = true;
    }

    // throw up an indeterminate system dialog to indicate radio is
    // shutting down.
    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);

    pd.show();

    sInstance.mContext = context;
    sInstance.mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE);

    // make sure we never fall asleep again
    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;
    }

    // also make sure the screen stays on for better user experience
    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;
        }
    }

    // start the thread that initiates shutdown
    sInstance.mHandler = new Handler() {
    };
    sInstance.start();
 }

至此关于代码部分的改动全部完成，接下来就需要添加使用到的资源了，就是前面用到的字符串。首先需要在frameworks/base/core/res/res/values/strings.xml中添加一下字符串：

 <string name="reboot">Reboot</string>
 <string name="reboot_progress">Reboot\u2026</string>
 <string name="reboot_confirm" product="tablet">Your tablet will reboot.</string>
 <string name="reboot_confirm" product="default">Your phone will reboot.</string>
 <!-- label for item that reboot in phone options dialog -->
 <string name="global_action_reboot">Reboot</string>

而后需要在frameworks/base/core/res/res/values/public.xml中声明这些资源，否则编译的时候会出现找不到该资源的错误。

 <java-symbol type="string" name="reboot" />
 <java-symbol type="string" name="reboot_confirm" />
 <java-symbol type="string" name="reboot_progress" />
 <java-symbol type="string" name="global_action_reboot" />

至此，全部修改完成，编译烧写即可。