Question

Do you have better way to make the device awakes by 100%? I repeatedly call the acquire() but I’m not sure if that is correct. Or should I just call the acquire() once? Or should I make use of Intent.ACTION_SCREEN_OFF?

public class MyServiceThatKeepsTheDeviceAwake extends IntentService {   
TAG = "com.android.browser.test.launcher.BrowsePageService";
...
@Override
public void onCreate() {
    super.onCreate();
    mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
    mWakeLock = mPowerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK |PowerManager.ACQUIRE_CAUSES_WAKEUP |PowerManager.ON_AFTER_RELEASE, TAG);
}

@Override
public void onStart(Intent intent, int startId) {
    super.onStart(intent, startId);
    mWakeLock.acquire();
}

// No release

*This service is run using AlarmManager every 20 seconds

—Added:

*This gives me the ff. output when repeatedly running it. Should there be any problem with this? Should there be any problem call it repeatedly?

C:\Windows\System32>adb shell dumpsys power
Power Manager State:
mIsPowered=false mPowerState=3 mScreenOffTime=463571 ms
mPartialCount=9
mWakeLockState=SCREEN_BRIGHT_BIT SCREEN_ON_BIT
mUserState=
mPowerState=SCREEN_BRIGHT_BIT SCREEN_ON_BIT
mLocks.gather=SCREEN_BRIGHT_BIT SCREEN_ON_BIT
mNextTimeout=355968 now=463589 -107s from now
mDimScreen=true mStayOnConditions=0
mScreenOffReason=0 mUserState=0
mBroadcastQueue={-1,-1,-1}
mBroadcastWhy={0,0,0}
mPokey=0 mPokeAwakeonSet=false
mKeyboardVisible=false mUserActivityAllowed=true
mKeylightDelay=6000 mDimDelay=2000 mScreenOffDelay=7000
mPreventScreenOn=false  mScreenBrightnessOverride=-1  mButtonBrightnessOverride=-1
mScreenOffTimeoutSetting=15000 mMaximumScreenOffTimeout=2147483647
mLastScreenOnTime=19531
mBroadcastWakeLock=UnsynchronizedWakeLock(mFlags=0x1 mCount=0 mHeld=false)
mStayOnWhilePluggedInScreenDimLock=UnsynchronizedWakeLock(mFlags=0x6 mCount=0 mHeld=false)
mStayOnWhilePluggedInPartialLock=UnsynchronizedWakeLock(mFlags=0x1 mCount=0 mHeld=false)
mPreventScreenOnPartialLock=UnsynchronizedWakeLock(mFlags=0x1 mCount=0 mHeld=false)
mProximityPartialLock=UnsynchronizedWakeLock(mFlags=0x1 mCount=0 mHeld=false)
mProximityWakeLockCount=0
mProximitySensorEnabled=false
mProximitySensorActive=false
mProximityPendingValue=-1
mLastProximityEventTime=0
mLightSensorEnabled=true
mLightSensorValue=1219.0 mLightSensorPendingValue=1173.0
mLightSensorPendingDecrease=true mLightSensorPendingIncrease=false
mLightSensorScreenBrightness=122 mLightSensorButtonBrightness=0 mLightSensorKeyboardBrightness=0
mUseSoftwareAutoBrightness=true
mAutoBrightessEnabled=true
mScreenBrightness: animating=false targetValue=122 curValue=122.0 delta=0.45

mLocks.size=16:
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
FULL_WAKE_LOCK                 'com.android.browser.test.launcher.BrowsePageService'ACQUIRE_CAUSES_WAKEUP  activated (minState=3, uid=10040, pid=722)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase.lastChance' activated (minState=0, uid=10007, pid=243)
PARTIAL_WAKE_LOCK              'WSBase' activated (minState=0, uid=10007, pid=243)

mPokeLocks.size=0:

Answer 1

No need to call acquire() repeatedly.Just in onCreate() acquire lock.It will work until you do not call release().Just in onDestroy() of activity call release(), As it battery consuming task.

For more detail look at this Detail Discussion on Wake up of Screen