android - OnPause and OnStop() called immediately after starting activity -

i have activity needs turn screen on(if offed) when started. in oncreate, have:

this.getwindow().setflags(             windowmanager.layoutparams.flag_keep_screen_on                     | windowmanager.layoutparams.flag_show_when_locked                     | windowmanager.layoutparams.flag_turn_screen_on,             windowmanager.layoutparams.flag_keep_screen_on                     | windowmanager.layoutparams.flag_show_when_locked                     | windowmanager.layoutparams.flag_turn_screen_on); 

using of wakelock in broadcasr receiver , able cause activity display whenever started broadcast receiver.

but problem strange, activity lifecycle calls in manner, onpause() , onresume after starting activity

1. oncreate
2. onstart
3. onresume
4. onpause
5. onstop
6. onstart
7. onresume

---

so problem on start , on resume calling twice, on stop calling, want implement logic in onstop() but, such behavior app not work correctly.

edit

i found problem due flag flag_show_when_locked. , when device locked. , happens when device locked before activity starting.

p.s using alarm manager broadcast receiver, , starts activity broadcast receiver.

• let understand why lifecycle methods called multiple times.

here important code comment documented in activitythread, responsible executing activities of application process.

we accomplish going through normal startup (because activities expect go through onresume() first time run, before window displayed), , pausing it.

right after onresume, activity window attached window manager , onattachedtowindow invoked. if screen on, activity window focus , onwindowfocuschanged invoked true parameter. docs:

keep in mind onresume not best indicator activity visible user; system window such keyguard may in front. use onwindowfocuschanged(boolean) know activity visible user

in reported issue, screen if off. hence activity window not focus, results in activity's onpause method getting called followed onstop method, activity window not visible.

since windowmanager.layoutparams.flag_turn_screen_on flag set on activity window, window manager service turns on screen using power manager api. following windowmanagerservice code:

public int relayoutwindow(...) {     ...     tobedisplayed = !win.isvisiblelw();     ...     if (tobedisplayed) {         ...         if ((win.mattrs.flags             & windowmanager.layoutparams.flag_turn_screen_on) != 0) {             if (debug_visibility) slog.v(tag,                 "relayout window turning screen on: " + win);                 win.mturnonscreen = true;             }         ...         if (mturnonscreen) {             if (debug_visibility) slog.v(tag, "turning screen on after layout!");             mpowermanager.wakeup(systemclock.uptimemillis());             mturnonscreen = false;         }         ... } 

after screen turns on onstart , onpause called again.

hence : oncreate - onstart - onresume - onpause - onstop - onstart - onpause.

this can verified locking device , starting activity using adb command or eclipse.

• ideal solution

if start task in oncreate need stop in ondestory (if task still pending). onstart onstop , onresume onpause.

• workaround

if can't follow above protocol, can check status of activity window focus using haswindowfocus in onpause method. activity window focus status true in onpause. in scenarios screen off or screen on keyguard displayed, activity window focus false in onpause.

boolean mfocusduringonpause;  public void onpause() {     super.onpause;      mfocusduringonpause = haswindowfocus();     }  public void onstop() {     super.onstop();      if(mfocusduringonpause) {         // normal scenario     } else {         // activity started when screen off / screen on keygaurd displayed     } }