Does onDestroy() or finish() actually kill the activity?

Question

Actually I know i am asking about the simple and basic concept of Android. But I am a little bit confused about these finish() and onDestroy() meth

Answer 1

The default behavior is that back button will cause the activity to exit and it'll be destroyed. Displaying a toast in onDestroy or onPause is not a good idea though. It'll alter the lifecycle the of your activity in a way you don't want it to happen. Use logging instead, so you'll see what's really happening. BTW, finish() is something that you call explicitly from your code and onDestroy() is a lifecycle event/method which gets called as a result of finishing/destoying the activity in any way.

Answer 2

Finish() will literally finish your activity and if no references are present a GC will recover resources. onDestory() is actually a method that the system will call when it is destroying your activity and you are supposed to implement this function. You dont need to worry avout destroying your app , android does it for you.

Answer 3

The finish() kills the activity and releases memory... unless you have some reference stored that is leaked... for example on methods like onRetainNonConfigurationInstance()

When you press the back button what is called is the finish() method that than calls onPause, onStop, onDestroy.