android - Delay while launching activity from service -

i have broadcast receiver receives screen off broadcast, , when screen turned off, launches activity. i've named activity lockscreenactivity. i've added getwindow().addflags(windowmanager.layoutparams.flag_show_when_locked); in oncreate() of activity, appears on top of android lockscreen, want. works enough, mostly. problem happens whenever press home button send any app background.

when press home button return home screen app, , press power button turn off screen, , press power button in second turn in on, shows android lock screen. activity gets created 3-4 seconds later. huge delay , unacceptable. in other scenarios, delay not happen. if i've been in home screen time, or other app open, , click power button twice in quick succession, see lockscreenactivity before seeing android lockscreen.

my app has few other normal activities (launched app drawer) , service shows persistent notification. same lockscreenactivity launched whenever notification clicked. interestingly enough, if press home button minimize app , click notification of app, opens lockscreenactivity without delay.

i've searched lot solution. here's i've tried out far:

1. made broadcast receiver run in separate thread passing handler when registering broadcast receiver
2. acquired wakelock in broadcast receiver's onreceive() , released in onresume() of lockscreenactivity
3. made separate task stack lockscreenactivity specifying different taskaffinity in manifest. i've played lot of combinations of options related activity stack, nothing has helped far.
4. instead of launching activity directly, sent intent service launches activity. nothing has worked, unfortunately.

here's manifest declaration of activity, , service:

<activity         android:name=".lockscreenactivity"         android:label="@string/app_name"         android:excludefromrecents="true"         android:taskaffinity="@string/task_lockscreen"> </activity> <service         android:name=".services.baseservice"         android:enabled="true" > </service> 

broadcast receiver:

public class screenreceiver extends broadcastreceiver { private static final string log_tag = screenreceiver.class.getsimplename(); private static final string handler_thread_name = "screen_receiver_thread"; public static final string wakelock_tag = "lockscreen_overlay_create_wakelock";  @override public void onreceive(context context, intent intent) {     if (intent.getaction().equals(intent.action_screen_off)) {         wakelockhelper.acquirewakelock(wakelock_tag, context);         log.d(log_tag, "screen off");         context.startservice(baseservice.getserviceintent(context, null, baseservice.action_start_lockscreen_activity));     } else {         if (intent.getaction().equals(intent.action_screen_on)) {             log.d(log_tag, "screen on");         }     } }  public static void registerscreenreceiver(context context){     new broadcastreceiverregistration().execute(context); }  private static class broadcastreceiverregistration extends asynctask<context, void, void>{     @override     protected void doinbackground(context... params) {         context context = params[0];         if(utility.checkfornullandwarn(context, log_tag)){             return null;         }         handlerthread handlerthread = new handlerthread(handler_thread_name);         handlerthread.start();         looper looper = handlerthread.getlooper(); //will block till thread started, hence using asynctask         handler handler = new handler(looper);          intentfilter filter = new intentfilter(intent.action_screen_off);         filter.addaction(intent.action_screen_on);         broadcastreceiver mreceiver = new screenreceiver();          context.registerreceiver(mreceiver, filter, null, handler);         return null;     } } } 

wakelockhelper class manages wakelocks in app. registerscreenreceiver() called service when starts.

here's oncreate() of lockscreenactivity:

protected void oncreate(bundle savedinstancestate) {     log.d(log_tag, "lockscreenactivity oncreate()");     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_lock_screen);     if (savedinstancestate == null) {         getfragmentmanager().begintransaction()                 .add(r.id.container, new lockscreenfragment())                 .commit();     }     getwindow().addflags(windowmanager.layoutparams.flag_dim_behind);     getwindow().setdimamount((float) 0.4);     getwindow().addflags(windowmanager.layoutparams.flag_show_when_locked);      int systemuivisibilityflags = view.system_ui_flag_hide_navigation |             view.system_ui_flag_fullscreen |             view.system_ui_flag_layout_hide_navigation |             view.system_ui_flag_layout_fullscreen;     if(build.version.sdk_int >= build.version_codes.kitkat) {         systemuivisibilityflags = systemuivisibilityflags | view.system_ui_flag_immersive_sticky;     }     getwindow().getdecorview().setsystemuivisibility(systemuivisibilityflags); } 

here's log when things work expected: (screen intially on; turned off , on again)

09-19 11:00:09.384  31226-31243/com.pvsagar.smartlockscreen d/screenreceiver﹕ screen off 09-19 11:00:09.384  31226-31226/com.pvsagar.smartlockscreen d/baseservice﹕ starting lockscreen overlay. 09-19 11:00:09.394  31226-31226/com.pvsagar.smartlockscreen d/lockscreenactivity﹕ lockscreenactivity oncreate() 09-19 11:00:09.735  31226-31243/com.pvsagar.smartlockscreen d/screenreceiver﹕ screen on 

not delay between screen off , sending intent , lockscreenactivity starting. screen on; press home app (any app, other activity of own app); screen turned off , on again:

09-19 11:02:51.557  31226-31243/com.pvsagar.smartlockscreen d/screenreceiver﹕ screen off 09-19 11:02:51.557  31226-31226/com.pvsagar.smartlockscreen d/baseservice﹕ starting lockscreen overlay. 09-19 11:02:51.708  31226-31243/com.pvsagar.smartlockscreen d/screenreceiver﹕ screen on 09-19 11:02:54.851  31226-31226/com.pvsagar.smartlockscreen d/lockscreenactivity﹕ lockscreenactivity oncreate() 

here, can see, screen off broadcast received in time, service gets intent , send intent lockscreenactivity, oncreate() of lockscreenactivity delayed 3 seconds.

this how lockscreenactivity started service:

intent lockscreenintent = new intent(this, lockscreenactivity.class); lockscreenintent.addflags(intent.flag_activity_new_task); log.d(log_tag, "starting lockscreen overlay."); startactivity(lockscreenintent); 

this pending intent passed notification (just show same thing):

intent notificationintent = new intent(context, lockscreenactivity.class); notificationintent.addflags(intent.flag_activity_new_task); pendingintent pendingintent = pendingintent.getactivity(context, 0, notificationintent, 0); notificationbuilder.setcontentintent(pendingintent); 

i'm not having idea why happening. gc not running much. problem? can possibly overcome this? suggestions/ideas appreciated.

the entire code can found at: https://github.com/aravindsagar/smartlockscreen/tree/backend_code_strengthening

after digging, found out cause of problem. apparently it's not bug, feature not allow services or broadcastreceivers launch activities 5 seconds after home button pressed. no easy way overcome this.

more info here: https://code.google.com/p/android/issues/detail?id=4536

i replaced activity window added window manager of running service. not cause delay.