What is Activity.finish() method doing exactly?

Question

I\'m developing android applications for a while, and followed a lot of posts about activity life cycle, and application\'s life cycle.

I know Activity.finish

Answer 1

It seems that the only correct answer here so far has been given by romnex: "onDestroy() may not be called at all". Even though in practice, in almost all cases it will, there is no guarantee: The documentation on finish() only promises that the result of the activity is propagated back to the caller, but nothing more. Moreover, the lifecycle documentation clarifies that the activity is killable by the OS as soon as onStop() finishes (or even earlier on older devices), which, even though unlikely and therefore rare to observe in a simple test, might mean that the activity might be killed while or even before onDestroy() is executed.

So if you want to make sure some work is done when you call finish(), you cannot put it in onDestroy(), but will need to do in the same place where you call finish(), right before actually calling it.