Clear all activities in a task?
I have a splash screen activity, then a login activity. My history stack looks like:
when the user successfully logs in via LoginActivity, I want to start WelcomeActivity, but clear the entire stack:
Is there some flag I can use to do that?
Not sure if using the FLAG_ACTIVITY_CLEAR_TASK will clear out all activities in my task or not. I can do this ‘manually’ by unwinding the stack by using startActivityForResult() calls, but will be more fragile and more code to maintain.
7 Answers 7
Yes that should work fine. You could use:
- FLAG_ACTIVITY_CLEAR_TOP
- FLAG_ACTIVITY_SINGLE_TOP
- FLAG_ACTIVITY_CLEAR_TASK
- FLAG_ACTIVITY_NEW_TASK
which ensures that if an instance is already running and is not top then anything on top of it will be cleared and it will be used, instead of starting a new instance (this useful once you’ve gone Welcome activity -> Activity A and then you want to get back to Welcome from A, but the extra flags shouldn’t affect your case above).
Use android:noHistory=»true» on the splash activity in the manifest file.
finish() removes the activity from the stack. So, if you start LoginActivity and call finish() on SplashActivity, and then you do exact the same to start WelcomeActivity you will get the desired behaviour. No need to use extra flags.
Intent.FLAG_ACTIVITY_NO_HISTORY can work in your case too if you do not want the activity on the history stack.
Just do this to clear all previous activity in a task:
In case that all of three activity is involved in the same app(same taskAffinity), you can pick either 1,2 or 3 below. otherwise you should pick 1,2 below.
If you don’t want to return back SplashActivity from LoginActivity, you can define activity attribute noHistory in AndroidManifest.xml or you can set FLAG_ACTIVITY_NO_HISTORY into the intent to launch SplashActivity. if SplashActivity is started from Launcher, you should pick way to set activity attribute noHistory.
If you don’t want to return back LoginActivity from WelcomeActivity, you can use either activity attribute noHistory or FLAG_ACTIVITY_NO_HISTORY like number 1 above.
If you want to clear back stack on specific situation, you can use FLAG_ACTIVITY_CLEAR_TASK in conjunction with FLAG_ACTIVITY_NEW_TASK ( FLAG_ACTIVITY_CLEAR_TASK always must be used in conjunction with FLAG_ACTIVITY_NEW_TASK ). But, if the activity being started is involved in other app(i.e different taskAffinity), the task will be launched other task after the task is cleared, not current task. so make sure that the activity being launched is involved in the same app(taskAffinity).
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Android: Remove all the previous activities from the back stack
When i am clicking on Logout button in my Profile Activity i want to take user to Login page, where he needs to use new credentials.
Hence i used this code:
in the onButtonClick of the Logout button.
But the problem is when i click device back button on the Login Activity it takes me to the ProfileActivity. I was expecting the application should close when i press device back button on LoginActivity.
What am i doing wrong?
I also added android:launchMode=»singleTop» in the manifest for my LoginActivity
18 Answers 18
The solution proposed here worked for me:
Kotlin
However, it requires API level >= 11.
Here is one solution to clear all your application’s activities when you use the logout button.
Every time you start an Activity, start it like this:
When you want to close the entire app, do this:
RESULT_CLOSE_ALL is a final global variable with a unique integer to signal you want to close all activities.
Then define every activity’s onActivityResult(. ) callback so when an activity returns with the RESULT_CLOSE_ALL value, it also calls finish() :
This will cause a cascade effect that closes all your activities.
This is a hack however and uses startActivityForResult in a way that it was not designed to be used.
Perhaps a better way to do this would be using broadcast receivers as shown here:
See these threads for other methods as well:
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Finish all previous activities
My application has the following flow screens :
Home->screen 1->screen 2->screen 3->screen 4->screen 5
Now I have a common log out button in each screens
( Home/ screen 1 / screen 2 /screen 3/ screen 4 / screen 5 )
I want that when user clicks on the log out button(from any screen), all the screens will be finished and a new screen Log in will open .
I have tried nearly all FLAG_ACTIVITY to achieve this. I also go through some answers in stackoverflow, but not being able to solve the problem. My application is on Android 1.6 so not being able to use FLAG_ACTIVITY_CLEAR_TASK
Is there any way to solve the issue ?
27 Answers 27
This will clear all the activities on top of home.
Assuming you are finishing the login screen when the user logs in and home is created and afterwards all the screens from 1 to 5 on top of that one. The code i posted will return you to home screen finishing all the other activites. You can add an extra in the intent and read that in the home screen activity and finish it also (maybe launch login screen again from there or something).
I am not sure but you can also try going to login with this flag. I don’t know how the activities will be ordered in that case. So don’t know if it will clear the ones below the screen you are on including the one you are currently on but its definitely the way to go.
Hope this helps.
You may try Intent.FLAG_ACTIVITY_CLEAR_TASK|Intent.FLAG_ACTIVITY_NEW_TASK . It will totally clears all previous activity(s) and start new activity.
Before launching your new Activity, simply add the following code:
Or if you want it to work in previous versions of Android:
When the user wishes to exit all open activities, they should press a button which loads the first Activity that runs when your application starts, clear all the other activities, then have the last remaining activity finish. Have the following code run when the user presses the exit button. In my case, LoginActivity is the first activity in my program to run.
The above code clears all the activities except for LoginActivity . Then put the following code inside the LoginActivity ‘s onCreate(. ) , to listen for when LoginActivity is recreated and the ‘EXIT’ signal was passed:
Why is making an exit button in Android so hard?
Android tries hard to discourage you from having an «exit» button in your application, because they want the user to never care about whether or not the programs they use are running in the background or not.
The Android OS developers want your program to be able to survive an unexpected shutdown and power off of the phone, and when the user restarts the program, they pick up right where they left off. So the user can receive a phone call while they use your application, and open maps which requires your application to be freed for more resources.
When the user resumes your application, they pick up right where they left off with no interruption. This exit button is usurping power from the activity manager, potentially causing problems with the automatically managed android program life cycle.
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Is it possible to clear all previous activities in this task?
Is it possible to clear all previous activities only in this current task? So, my stack of activities looks like this:
Is it possible to launch E with some flag:
which will remove both activities C and D (all previous activities in current task), so after clicking Back in activity E app will return to the place where the new task was started (Activity B)? After starting activity E, the back stack should be like this:
3 Answers 3
If set, and the activity being launched is already running in the current task, then instead of launching a new instance of that activity, all of the other activities on top of it will be closed and this Intent will be delivered to the (now on top) old activity as a new Intent.
For example, consider a task consisting of the activities: A, B, C, D. If D calls startActivity() with an Intent that resolves to the component of activity B, then C and D will be finished and B receive the given Intent, resulting in the stack now being: A, B.
The currently running instance of activity B in the above example will either receive the new intent you are starting here in its onNewIntent() method, or be itself finished and restarted with the new intent. If it has declared its launch mode to be «multiple» (the default) and you have not set FLAG_ACTIVITY_SINGLE_TOP in the same intent, then it will be finished and re-created; for all other launch modes or if FLAG_ACTIVITY_SINGLE_TOP is set then this Intent will be delivered to the current instance’s onNewIntent().
This launch mode can also be used to good effect in conjunction with FLAG_ACTIVITY_NEW_TASK: if used to start the root activity of a task, it will bring any currently running instance of that task to the foreground, and then clear it to its root state. This is especially useful, for example, when launching an activity from the notification manager.
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clear all activities except one in android
Below I’m showing the flow on how I want to navigate my Activities :
I tried writing the following code inside D and E :
However, I’m facing two issues:
- When B gets launched it shows a grey screen for a while, then it gets loaded.
- When I go back from B it exits out of the application rather than going to A (the dashbord).
How can I fix this?
2 Answers 2
I believe you can achieve what you want by using FLAG_ACTIVITY_CLEAR_TOP. If you send an Intent using this flag, it will be delivered to the existing Activity B, and any activities above B on the stack (C, D/E) will be finished.
Using FLAG_ACTIVITY_CLEAR_TASK will finish all previous activities on the stack, which would make B the only remaining activity — explaining why you exit the app when clicking back. Your grey background is unrelated to activity management and indicates the activity is simply taking a while to call onCreate().
I think FLAG_ACTIVITY_CLEAR_TASK is clearing all the activities from stack.
to go back from activity B to A again, without changing anything to your existing code , simple overrride onBackPress() method in activity B and startActivity A there.
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