Android Alarm in Doze mode

Posted by Vector Blog on May 31, 2017

Whitelist in Alarm Service

DeviceIdleController 中会有两处设置 Alarm 的白名单:

mLocalAlarmManager = getLocalService(AlarmManagerService.LocalService.class);

    public void onBootPhase(int phase) {
        if (phase == PHASE_SYSTEM_SERVICES_READY) {
                mLocalAlarmManager.setDeviceIdleUserWhitelist(mPowerSaveWhitelistUserAppIdArray);

    private void updateWhitelistAppIdsLocked() {
            mLocalAlarmManager.setDeviceIdleUserWhitelist(mPowerSaveWhitelistUserAppIdArray);

最终就是设置到 AlarmManagerService 的 mDeviceUserWhiteList中：

    int[] mDeviceIdleUserWhitelist = new int[0];

    void setDeviceIdleUserWhitelistImpl(int[] appids) {
        synchronized (mLock) {
            mDeviceIdleUserWhitelist = appids;
        }
    }

再来看会用到 mDeviceIdleUserWhitelist 的地方, 只有 AlarmManagerService 的 set 方法内会用到, 如果是系统程序 UID 或者白名单程序则将 flag 中 FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED 置起来。

        public void set(String callingPackage,
                int type, long triggerAtTime, long windowLength, long interval, int flags,
                PendingIntent operation, IAlarmListener directReceiver, String listenerTag,
                WorkSource workSource, AlarmManager.AlarmClockInfo alarmClock) {
            ......
            } else if (workSource == null && (callingUid < Process.FIRST_APPLICATION_UID
                    || Arrays.binarySearch(mDeviceIdleUserWhitelist,
                            UserHandle.getAppId(callingUid)) >= 0)) {
                flags |= AlarmManager.FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED;
                flags &= ~AlarmManager.FLAG_ALLOW_WHILE_IDLE;
            }

Alarm Doze 激活

在调用 AlarmManager 的 setIdleUntil 时会激活 Alarm Doze 开启 ， 在 DeviceIdleController 中 deep idle 都会通过调用 setIdleUntil 来切换状态

    /**
     * Schedule an idle-until alarm, which will keep the alarm manager idle until the given time.
     * @hide
     */
    public void setIdleUntil(int type, long triggerAtMillis, String tag, OnAlarmListener listener,
            Handler targetHandler) {
        setImpl(type, triggerAtMillis, WINDOW_EXACT, 0, FLAG_IDLE_UNTIL, null,
                listener, tag, targetHandler, null, null);
    }

    private void setImpl(int type, long triggerAtMillis, long windowMillis, long intervalMillis,
            int flags, PendingIntent operation, final OnAlarmListener listener, String listenerTag,
            Handler targetHandler, WorkSource workSource, AlarmClockInfo alarmClock) {
            ......
            mService.set(mPackageName, type, triggerAtMillis, windowMillis, intervalMillis, flags,
                    operation, recipientWrapper, listenerTag, workSource, alarmClock);

调用到 AlarmManagerService 的 set 方法， 这里会对 falg 有很多的处理

        public void set(String callingPackage,
                int type, long triggerAtTime, long windowLength, long interval, int flags,
                PendingIntent operation, IAlarmListener directReceiver, String listenerTag,
                WorkSource workSource, AlarmManager.AlarmClockInfo alarmClock) {
            final int callingUid = Binder.getCallingUid();

            ......

            //先清除 FLAG_WAKE_FROM_IDLE 和 FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED
            flags &= ~(AlarmManager.FLAG_WAKE_FROM_IDLE
                    | AlarmManager.FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED);

            // this is used to tell the alarm manager when to come out of idle mode
            // which is only for DeviceIdleController.
            if (callingUid != Process.SYSTEM_UID) {
                flags &= ~AlarmManager.FLAG_IDLE_UNTIL;
            }

            // If this is an exact time alarm, then it can't be batched with other alarms.
            if (windowLength == AlarmManager.WINDOW_EXACT) {
                flags |= AlarmManager.FLAG_STANDALONE;
            }

            // If this alarm is for an alarm clock, then it must be standalone and we will
            if (alarmClock != null) {
                flags |= AlarmManager.FLAG_WAKE_FROM_IDLE | AlarmManager.FLAG_STANDALONE;

            // 如果是系统程序 或者 白名单内的应用 则将 FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED 置起
            } else if (workSource == null && (callingUid < Process.FIRST_APPLICATION_UID
                    || Arrays.binarySearch(mDeviceIdleUserWhitelist,
                            UserHandle.getAppId(callingUid)) >= 0)) {
                flags |= AlarmManager.FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED;
                flags &= ~AlarmManager.FLAG_ALLOW_WHILE_IDLE;
            }

            setImpl(type, triggerAtTime, windowLength, interval, operation, directReceiver,
                    listenerTag, flags, workSource, alarmClock, callingUid, callingPackage);
        }
CATALOG