可以在finish（）之后恢复Android活动吗？

Question

Checking some legacy code I've found this snippet:

@Override
public void onResume() {
    if (!isFinishing()) {
        ...
    }
    super.onResume();
}

despite the super.onResume() call at the end of the method, which is discouraged:

Note: Your implementation of these lifecycle methods must always call the superclass implementation before doing any work, as shown in the examples above http://developer.android.com/guide/components/activities.html

I'm concerned about the if (!isFinishing()) call, does this have sense? as I can see checking Activity code mFinished variable is set to true only on finish() and finishActivity() , can, through the Android Lifecycle, to be resumed an activity which is being destroyed?

Thanks in advance.

Answer 1

The answer to you question is "no" activity cannot be resumed if it was destroyed.
Here is good discussion: Understanding of isFinishing()

The reason for this code may be to distinguish between orientation change and actual finishing of the activity Important to note here is isFinishing: true which means that call to isFinishing() in the onDestroy() returns true, ie which happens when:

User hits "back" button OR activity's code calls it's finish() ( isFinishing() returns false when activity is geting closed after phone rotaion in order to be started again)

http://ogrelab.ikratko.com/activity-lifecycle-explained-in-details/

Answer 2

Finally, the legacy code was calling finish() under some circunstances at the onCreate() method. But taking a look at onCreate() javadoc :

You can call finish() from within this function, in which case onDestroy() will be immediately called without any of the rest of the activity lifecycle (onStart(), onResume(), onPause(), etc) executing.

So, this isFinishing() call is useless inside onResume()