What is the difference in lifecycle between lock screen and opening other application android -

i'm developing application right now, problem when pressed home or open whatsapp notification , reopen application, restarted beginning of application, instead of resuming state left.

while locking , unlocking screen resumes state left.

so, tried tracing life-cycle between 2 process (locking screen & opening other app/home). makes me confuse both process show same lifecycle , onpause() , onstop() triggered when locked screen or open other app/home. then, when returned app, onrestart() , onresume() triggered.

if both shows same result, why locking screen , unlocking continued application, while pressing home or application , reopen application did not?

any solution or explanation appreciated. thanks.

code :

@override protected void onrestart(){     system.out.println("restart");     super.onrestart(); }  @override protected void onresume(){system.out.println("resume");     gamepanel.resumeactivity();     super.onresume(); }  @override protected void onpause(){     gamepanel.pausemusic();     gamepanel.pauseactivity();     system.out.println("pause");     super.onpause(); } @override protected void onstop(){     system.out.println("stop");     super.onstop(); } @override protected void ondestroy(){     content.removeview(gamepanel);     content.removeview(edittext);     gamepanel.stopmusic();     system.out.println("destroy");     super.ondestroy(); } 

i think have use onsaveinstancestate(bundle savedinstancestate) achieve data @ time app destroyed. please take of that link, you.