Android - What is wrong with onStart method?

Question

I am trying to understand Android Activity lifecycle. For that purpose, I have created Activity where I have overridden all lifecycle methods(onCreate, onStart, onRestart, onResume, onPause, onStop, onDestroy):

public class SecondActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        Log.d("ActivityTutorial", "onCreate");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.d("ActivityTutorial", "onStart");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Log.d("ActivityTutorial", "onRestart");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.d("ActivityTutorial", "onResume");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.d("ActivityTutorial", "onPause");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.d("ActivityTutorial", "onStop");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("ActivityTutorial", "onDestroy");
    }

}

I put breakpoints on the lines where I am logging using Log.d(...). Then I tried to debug. onCreate method is okay - it is calling when activity is created.

Strange situation is starting onStart method. According to Android documentation: "onStart() Called when the activity is becoming visible to the user." But when I debug, it comes to onStart method but Button which is on this Activity, not visible yet.

I thought it supposed to be seen onResume() - after calling onStart() method. But button was not visible.

Only after onResume method, button was visible.

So my question is what is wrong with onStart and onResume methods? Maybe I am doing something not in the way it supposed to be done?

Answer 1

No. The onResume() method makes visible of Activity. As you said thanks to the Documentation: "onStart() Called when the activity is becoming visible to the user".

And if you read carefully: "onResume() Called when activity will start interacting with the user."

UPDATE:

Keep in mind that onResume is not the best indicator that your activity is visible to the user; a system window such as the keyguard may be in front. Use onWindowFocusChanged(boolean) to know for certain that your activity is visible to the user (for example, to resume a game).