How to reduce the time delay between Activity Pause and Re-Start(by a Service)?

Question

I am implementing an activity to be on top always ( generally implementing a lock screen), The Algorithm is simple as :

Start Activity
Disable All Hardware buttons, disable backpress,camera lock, volume buttons etc.
Whenever activity is paused call a service to check and restart the activity.

Refer to these answers for the logic: Answer 1, Answer 2 There is a 6-7 seconds delay whenever the Activity is paused, and is restarted by the Service. How may I reduce this time delay between the pause and restart of my Activity.

On Pause and On Resume Code:

protected void onPause() {
    isFront = false;
    Intent lockHelper = new Intent( this, LockHelper.class);
    startService( lockHelper );
    super.onPause();
}


@Override
public boolean onKeyDown(int keyCode, KeyEvent keyEvent) {
    if(keyCode==KeyEvent.KEYCODE_CAMERA)
        return true;
    else if(keyCode==KeyEvent.KEYCODE_VOLUME_DOWN)
        return true;
    else if(keyCode==KeyEvent.KEYCODE_VOLUME_UP)
        return true;
    else if(keyCode==KeyEvent.KEYCODE_HOME)
        return true;
    else if(keyCode==KeyEvent.KEYCODE_POWER)
        return true;
    else 
        return true;
}

@Override
public boolean onKeyLongPress(int keyCode, KeyEvent keyEvent) {
    if(keyCode==KeyEvent.KEYCODE_HOME)
        return true;
    else if(keyCode==KeyEvent.KEYCODE_POWER)
        return true;
    else 
        return true;
}

@Override
public void onBackPressed() {
}

@Override
protected void onResume() {
    isFront = true;
    Intent lockHelper = new Intent( this, LockHelper.class);
    startService( lockHelper );
    super.onResume();
}

}

Service is:

public class LockHelper extends Service {
@Override
public void onStart(Intent intent, int startId) {
    if(Locker.isFront == false){
        Intent locker = new Intent( this, Locker.class);
        locker.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity( locker );
        stopSelf();
    }
}

public LockHelper() {
}

@Override
public IBinder onBind(Intent intent) {
    throw new UnsupportedOperationException("Not yet implemented");
}
}

I suggest you do a more detailed timestamp debugging, is the `6-7 seconds` calculated based on your instinct? You may log a message on Activity.onPause(), Service.onStart(), Activity.onCreate() and Activity.onResume(). This way you know which part is taking a lot of time based on Log timestamp. And take away stopSelf, place your codes on onStartCommand instead, recreation of service may takes significant amount of time, and I believe that is where your delay happens. — Chor Wai Chun, May 05 '13 at 07:02
@ChorWaiChun no not on basis of instinct actually the Activity has a clock in its layout, i check the time by the clock, i.e the number of second for which the Activity is hidden. — Rachit Mishra, May 05 '13 at 07:05
well then I'd suggest you make a little changes on your service based on my previous comments. — Chor Wai Chun, May 05 '13 at 07:07
@RachitMishra I am facing same issue. Did you get the solution? — Ankur Raiyani, Apr 11 '16 at 11:02
@RachitMishra ok Thanks ! Can you share what was the approached you followed? — Ankur Raiyani, Apr 12 '16 at 09:59
Yea! so if you are now making a lock service, you should explore accessibility service in Android. — Rachit Mishra, Apr 12 '16 at 14:51

score 1 · Accepted Answer · answered May 05 '13 at 06:47

1

The code in your onPause, onStop and onDestroy should execute as fast as possible. That is to say, don't block these methods by putting a lot of code here. But again, it depends on what you are doing here. If those things are really important, I am not sure how you can reduce the time delay.

answered May 05 '13 at 06:47

Kumar Bibek

9,016
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The code in these methods simple start a service, which check if the Activity is in background, and restarts the Activity. – Rachit Mishra May 05 '13 at 06:49
I agree with @Kumar Bibek, its your code efficiency in your onPause, onStop and onDestroy will matter. Use disable code only to those, which are really neccessary. – CRUSADER May 05 '13 at 06:51
I get exactly 6 seconds delay. :| – Rachit Mishra May 05 '13 at 06:58

score 0 · Answer 2 · answered May 05 '13 at 07:03

"is how may I reduce this time delay between the pause and restart of my Activity."

Did you measure the time cost happened this two interval?

Basically, two type of task: one is system task and your app task.

adb logcat -b system -v threadtime should print out all the system bahvoir related to Activity/Service start/stop, along with the timestamp.

You should/could reduce the time spend on your app as much as possible but there is no way to reduce the time cost of system behavior.

How to reduce the time delay between Activity Pause and Re-Start(by a Service)?

2 Answers2