How to get an Android WakeLock to work

Question

My WakeLock isn t keeping my device awake   In OnCreate   I ve got   PowerManager pm    PowerManager  getSystemService Context POWER SERVICE   mWakeLock   pm newWakeLock PowerManager SCREEN DIM WAKE LOCK   PowerManager ON AFTER RELEASE   My Tag    mWakeLock acquire      then   new CountDownTimer 1320000  200         public void onTick long millisUntilFinished               I update a progress bar here                                                      public void onFinish                I finish updating the progress bar          mWakeLock release            start      The screen turns off before the timer finishes  how can I make the screen stay visible   mWakeLock is a field previously declared like so   private PowerManager WakeLock mWakeLock    My device uses Android 1 6   I would really appreciate any help to resolve this

User · Answer

Keep the Screen On  First way   getWindow   addFlags WindowManager LayoutParams FLAG KEEP SCREEN ON     Second way    lt RelativeLayout xmlns android  http   schemas android com apk res android      android layout width  match parent      android layout height  match parent      android keepScreenOn  true  gt           lt  RelativeLayout gt    Keep the CPU On    lt uses-permission android name  android permission WAKE LOCK    gt    and  PowerManager powerManager    PowerManager  getSystemService POWER SERVICE   WakeLock wakeLock   powerManager newWakeLock PowerManager PARTIAL WAKE LOCK   MyWakelockTag    wakeLock acquire      To release the wake lock  call wakelock release    This releases your claim to the CPU  It s important to release a wake lock as soon as your app is finished using it to avoid draining the battery   Docs here

User · Answer

Do you have the required permission set in your Manifest    lt uses-permission android name  android permission WAKE LOCK    gt

User · Answer

Make sure that mWakeLock isn t accidentally cleaned up before you re ready to release it  If it s finalized  the lock is released  This can happen  for example  if you set it to null and the garbage collector subsequently runs  It can also happen if you accidentally set a local variable of the same name instead of the method-level variable   I d also recommend checking LogCat for entries that have the PowerManagerService tag or the tag that you pass to newWakeLock

User · Answer

You just have to write this    private PowerManager WakeLock wl       protected void onCreate Bundle savedInstanceState                   super onCreate savedInstanceState               setContentView R layout main                PowerManager pm    PowerManager  getSystemService Context POWER SERVICE               wl   pm newWakeLock PowerManager FULL WAKE LOCK   DoNjfdhotDimScreen           End of onCreate               Override         protected void onPause                 super onPause                wl release               End of onPause           Override         protected void onResume                 super onResume                wl acquire               End of onResume   and then add permission in the manifest file    lt uses-permission android name  android permission WAKE LOCK    gt    Now your activity will always be awake  You can do other things like w1 release   as per your requirement

User · Answer

WakeLock doesn t usually cause Reboot problems  There may be some other issues in your coding  WakeLock hogs battery heavily  if not released after usage   WakeLock is an Inefficient way of keeping the screen on  Instead use the WindowManager to do the magic  The following one line will suffice the WakeLock  The WakeLock Permission is also needed for this to work  Also this code is more efficient than the wakeLock   getWindow   addFlags WindowManager LayoutParams FLAG KEEP SCREEN ON     You need not relase the WakeLock Manually  This code will allow the Android System to handle the Lock Automatically  When your application is in the Foreground then WakeLock is held and else android System releases the Lock automatically   Try this and post your comment

User · Answer

Add permission in AndroidManifest xml    lt uses-permission android name  android permission WAKE LOCK    gt    Then add code in my xml   android keepScreenOn  true    in this case will never turn off the page  You can read more this

User · Answer

PowerManager mgr    PowerManager context getSystemService Context POWER SERVICE   WakeLock wakeLock   mgr newWakeLock PowerManager PARTIAL WAKE LOCK  MyWakeLock     wakeLock acquire       use this code and don t forget to permit wakelock in android manifest

User · Answer

Thank you for this thread  I ve been having a hard time implementing a Timer in my code for 5 minutes to run an activity  because my phone I have set to screen off sleep around 2 minutes  With the above information it appears I have been able to get the work around        Override public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState           Time Lockout after 5 mins        getWindow   addFlags LayoutParams FLAG KEEP SCREEN ON        Timer timer   new Timer        timer schedule new TimerTask             public void run              Intent i   new Intent AccountsList this  AppEntryActivity class           i setFlags Intent FLAG ACTIVITY CLEAR TOP           startActivity i           finish            return                    300000           Time Lockout END

User · Answer

I am having a similar problem  I can get the screen to stay on  but if I use a partial wake lock and the screen is turned off  my onFinish function isn t called until the screen is turned on   You can check your wake lock using mWakeLock isHeld    first of all  to make sure you re getting it  Easiest way is to add that to the code  set a breakpoint on it in the debugger  and then check it   In my case  I m getting it  but the partial wake lock doesn t seem to be doing anything  Here s my working code for the screen dim lock   protected void setScreenLock boolean on           if mWakeLock    null               PowerManager pm    PowerManager  getSystemService Context POWER SERVICE               mWakeLock   pm newWakeLock PowerManager SCREEN DIM WAKE LOCK                                           PowerManager ON AFTER RELEASE  TAG                     if on            mWakeLock acquire             else              if mWakeLock isHeld                     mWakeLock release                           mWakeLock   null                     ADDENDUM   Droid Eris and DROID users are reporting to me that this DOES NOT work on their devices  though it works fine on my G1  What device are you testing on  I think this may be an Android bug

User · Answer

To achieve the same programmatic you can use following  getWindow   addFlags WindowManager LayoutParams FLAG KEEP SCREEN ON     or adding following in layout also will perform the above task   android keepScreenOn  true    The details you can get from following url http   developer android com training scheduling wakelock html  I have used combination of following to wake my screen when keyguard locked and keep my screen on  getWindow   addFlags WindowManager LayoutParams FLAG KEEP SCREEN ON   getWindow   addFlags WindowManager LayoutParams FLAG TURN SCREEN ON   getWindow   addFlags WindowManager LayoutParams FLAG DISMISS KEYGUARD

User · Answer

sample code snippet from android developers site  public class MainActivity extends Activity      Override   protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main       getWindow   addFlags WindowManager LayoutParams FLAG KEEP SCREEN ON         Best Practices for Background Jobs

User · Answer

Add permission in AndroidManifest xml  as given below   lt uses-permission android name  android permission WAKE LOCK    gt    preferably BEFORE your  lt application gt  declaration tags but AFTER the  lt manifest gt  tags  afterwards  try making your onCreate   method contain only the WakeLock instantiation     Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       PowerManager pm    PowerManager getSystemService Context POWER SERVICE       mWakeLock   pm newWakeLock PowerManager SCREEN DIM WAKE LOCK   PowerManager ON AFTER RELEASE   My Tag        and then in your onResume   method place   Override public void onResume        mWakeLock aquire        and in your onFinish   method place   Override public void onFinish        mWakeLock release

User · Answer

Try using the ACQUIRE CAUSES WAKEUP flag when you create the wake lock   The ON AFTER RELEASE flag just resets the activity timer to keep the screen on a bit longer    http   developer android com reference android os PowerManager html ACQUIRE CAUSES WAKEUP

[android] How to get an Android WakeLock to work?

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