CODEWITHSUNDEEP
androidwakelock
CQM
CQM

Reputation: 44278

Android PowerManager and Wakelock, help me understand

so I am looking into PowerManager to prevent phone from going to sleep.

Two questions:

1) My phone is currently set to turn the display off after X seconds, will the PowerManager.Wakelock functions override this?

2) My phone has a top button which can be used to turn off the display, or shut the phone off. Will PowerManager.WakeLock override this functionality as well?

insight appreciated

Upvotes: 0

Views: 2929

Answers (2)

Rohit
Rohit

Reputation: 603

1) Yes, of course! If screen is ON and you acquire wakelock,then screen will remain ON even after Screen timeout. If screen is OFF and you want to turn it ON, then you have to create wakelock instance like this and acquire.

   PowerManager.WakeLock wl = pm.newWakeLock(
   PowerManager.SCREEN_DIM_WAKE_LOCK
  | PowerManager.ACQUIRE_CAUSES_WAKEUP, TAG);
  wl.acquire();

This will force your screen ON.

2) No wakelock can't override that functionality. Though I disagree with Yury, Top button is just switching the screen OFF and is not calling the goToSleep(long time) method. So it will not release partial wakelock untill unless you shut the device OFF.

Upvotes: 1

Yury
Yury

Reputation: 20936

  1. I'm not sure but I think so. And it's hard to me to find this functionality in the sources.

  2. There is a function in PowerManager.java goToSleep(time). This function simply calls method of PowerManagerService goToSleepLocked:

    private void goToSleepLocked(long time, int reason) {

if (mLastEventTime <= time) {
mLastEventTime = time;
// cancel all of the wake locks
mWakeLockState = SCREEN_OFF;
int N = mLocks.size();
int numCleared = 0;
boolean proxLock = false;

for (int i=0; i<N; i++) {
    WakeLock wl = mLocks.get(i);
    if (isScreenLock(wl.flags)) {
        if (((wl.flags & LOCK_MASK) == PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK)
             && reason == WindowManagerPolicy.OFF_BECAUSE_OF_PROX_SENSOR) {
        proxLock = true;
        } else {
            mLocks.get(i).activated = false;
            numCleared++;
        }
    }
}
if (!proxLock) {
    mProxIgnoredBecauseScreenTurnedOff = true;
    if (mDebugProximitySensor) {
        Slog.d(TAG, "setting mProxIgnoredBecauseScreenTurnedOff");
    }
}
EventLog.writeEvent(EventLogTags.POWER_SLEEP_REQUESTED, numCleared);
mStillNeedSleepNotification = true;
mUserState = SCREEN_OFF;
setPowerState(SCREEN_OFF, false, reason);
cancelTimerLocked();
}
}

So you can see that all wakelocks are shutdowned in this method.

The method goToSleep can be called only by system components (protected with signature permission). And I think that it is called during the press of your power button. So it rewrites all the wakelocks.

Upvotes: 1

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