Why does the main activity restart again after its called intent finished (Android 4.2.2)?

问题

The application works well in Android 2.3.5 But it does not work as desired in Nexus 4 (Android 4.2.2).

The application is: In the onCreate of main activity, it calls another activity through intent.

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final Intent launchIntent = new Intent(MainActivity.this, AndroidVideoCapture.class);
    launchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_SINGLE_TOP);
    startActivity(launchIntent);

    // I add a button dynamically here
}

Now with Nexus 4, after it finishes the intent of AndroidVideoCapture, it returns back to the begining of the onCreate, "setContentView(R.layout.activity_main);". So the intent restarts again and again.

Why?

回答1:

Try adding

if (savedInstanceState == null) {
    final Intent launchIntent = new Intent(MainActivity.this, AndroidVideoCapture.class);
    launchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_SINGLE_TOP);
    startActivity(launchIntent);
}

savedInstanceState not being null means the activity is being recreated.

回答2:

You can check if you have enabled 'Don't Keep Activities' in the developer options on the nexus 4 device. If checked, Disable that. This is an option available only since 4.0 and this is the reason behind your parent activity being 'recreated'.

来源：https://stackoverflow.com/questions/16424430/why-does-the-main-activity-restart-again-after-its-called-intent-finished-andro