Which method is called after an intent starts an Activity?

Question

I know that when an activity is first created its onCreate() method comes into play.

Assume that there's a main activity which starts another activity (secondActivity.java) through an intent and then that second activity starts the main activity again through an intent. My question is that whether onRestart() method is called of the main activity after receiving the intent or is onCreate() method called?

Thanks in advance!

Answer 1

My question is that whether onRestart() method is called of the main activity after receiving the intent or is onCreate() method called?

That depends on whether a new instance of the main activity will be created.

By default, one will. In that case, the new instance of the main activity will be called with onCreate(). The original instance of the main activity is left alone.

However, via Intent flags (e.g., FLAG_ACTIVITY_REORDER_TO_FRONT) or manifest settings, you could arrange to have the original instance of the main activity brought back to the foreground. In that case, the original instance will be called with onNewIntent() (to provide you with the Intent used with startActivity() that brought the activity back to the foreground). It should also be called with onRestart(), onStart(), and onResume() as part of coming back to the foreground.

Answer 2

Here is an image from the Android life cycle from the documentation:

When you launch a second activity onPause(), etc will be called on the first Activity then onCreate() and so on will be called on the second activity. As you can see in the diagram above when you press back onRestart() should be called on the first activity.

Answer 3

If you start a new intent the onCreate() method is called.