CODEWITHSUNDEEP
android
Nicos
Nicos

Reputation: 303

Weird Activity Lifecycle.

When i first start an activity from my main activity, it goes through the onCreate() then onStart(). While in the app, if i turn off the screen, it goes to onPause() where i save some data. Then immediately goes to onStop(), then onDestroy(), then again, without turning on the screen to onCreate(), onStart(), onPause(). Should it go to onCreate(), onStart() right after onDestroy(), without me doing anything?

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_timegame);

}

@Override
protected void onResume() {
    super.onStart();
    if (checkFirstTimeRun())
        initializeGame();
    else
        resumeGame();
}

@Override
protected void onPause() {
    super.onPause();
    saveGameData();
}

Upvotes: 1

Views: 93

Answers (2)

dragi
dragi

Reputation: 3525

I have observed the same behaviour on a tablet, with only landscape mode. It turns out that when the screen goes off, it is considered portrait mode. That's why during screen lock the activity is once destroyed for the screen off itself and then it goes all the way into portrait mode and it is again destroyed.
I have read this here on SO, but I cannot recall where it was, to link against it.

Upvotes: 0

Devrath
Devrath

Reputation: 42824

Shorter Explanation(Considering you are not using fragments):

  • Creation of activity is OnCreate,OnStart,OnResume
  • When you rotate the screen OnPause,OnStop,OnDestroy- Again OnCreate,OnStart,OnResumebecause activity is destroyed and recreated onOrientation change

Thus, if you won't rotate OnCreate,OnStart,OnResume is not fired for the second time !

Understand the Which events are executed and when:

Have a look at one of my answers i posted in stackoverflow - Click Here

A Use case Example(Considering you are using fragments):

Sample Project:

I have an opensource project Download it here and execute it and see the log to understand >the sequence of events executes one after another(I have fragment also in this project exclude the >fragment logs if you don't need it)

Project Observations

  • If the path is Activity-FragmentOne and change the orientation for the first time then the events fired are as follows MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume

  • If the path is Activity-FragmentOne-orientationchange and change the orientation for the first time then the events fired are as follows

MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume

  • If the path is Activity-FragmentOne-orientationchange-orientationchange and change the orientation for the first time then the events fired are as follows

MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume

  • If the path is Activity-FragmentOne-orientationchange-orientationchange-FragmentTwo and change the orientation for the first time then the events fired are as follows

MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onStop- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentTwo-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume

  • If the path is Activity-FragmentOne-orientationchange-orientationchange-FragmentTwo-orientationchange and change the orientation for the first time then the events fired are as follows

MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentOne-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onStop- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentTwo-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume- FragmentOne-onPause- FragmentOne-onSaveInstanceState- FragmentOne-onSaveInstanceState- FragmentOne-onStop- FragmentOne-onDestroy- FragmentOne-onDetach- FragmentOne-onDestroy- FragmentOne-onDetach- MainActivity-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onAttach- FragmentOne-onCreate- FragmentOne-onCreateView- FragmentTwo-onActivityCreated- FragmentOne-onStart- FragmentOne-onResume

Upvotes: 4

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