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：

/**
 * 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。