When Android kills an app, can a function be stopped halfway?

Question

I am wondering: when an app is to be killed, does Android wait for the currently running function to return, or does Android stop it before it ends by itself?

Answer 1

Your app may be killed by the system at any time without another line of its code being executed. According to the documentation however, there are a few methods which are not "killable":

• onCreate()
• onRestart()
• onStart()
• onResume()
• onPause()

As onDestroy() won't get called for sure, it is more save to use the onPause() Method to write any persistent data to storage:

protected void onPause(){
   super.onPause();
   if(isFinishing()){
      // store data
   }
}