Could someone provide a description of what happens when an Activity
calls its finish()
method?
Does it exit immediately, or does it complete the function from which it was called?
finishActivity(int requestCode) is used to finish another activity that you had previously started with startActivityForResult(Intent, int)
Using activity. isFinishing() is the right one solution. it return true if activity is finished so before creating dialog check for the condition. if true then create and show dialog.
As onCreate() of an Activity is called only once, this is the point where most initialization should go: calling setContentView(int) to inflate the activity's UI, using findViewById to programmatically interact with widgets in the UI, calling managedQuery(android.
finish () just sends back to the previous activity in android, or may be you can say that it is going one step back in application. Follow this answer to receive notifications.
Does it exits immediately or completes the function from which it was called ?
The method that called finish()
will run to completion. The finish()
operation will not even begin until you return control to Android.
Every life cycle event like onCreate
, onResume
, onPause
.... onDestroy
of an Activity is always called on a single thread - The "Main thread".
In short this thread is backed by a Queue into which all the activity events are getting posted. This thread can execute all these events in the order of insertion.
If you are calling finish()
in one of the life cycle callbacks like onCreate()
...a "finish" message will get added to this queue but the thread is not free to pick & execute "finish" action
until currently executing method returns i.e Thread is freed from current task.
ondestroy()
is the final call you receive before your activity is destroyed.
This can happen either because the activity is finishing (someone called finish()
on it, or because the system is temporarily destroying this instance of the activity to save space. You can distinguish between these two scenarios with the isFinishing()
method.
If there are two activities A and B. And your flow is going from A > B; and B=A calls finish()
.
Then,
The method where you called finish()
from will execute as Mark mentioned. And flow of callbacks will be as followed -
onPause()
of activity A
onRestart()
> onStart()
> onResume()
of Activity Bfinish()
from activity A
; only onStop()
of Activity A
will be called here. While, in this case, where we called finish()
from Activity A
; So onStop()
and onDestroy()
both will be called for activity A
.If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With