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Android: Clear the back stack

In Android I have some activities, let's say A, B, C.

In A, I use this code to open B:

Intent intent = new Intent(this, B.class);
startActivity(intent);

In B, I use this code to open C:

Intent intent = new Intent(this, C.class);
startActivity(intent);

When the user taps a button in C, I want to go back to A and clear the back stack (close both B and C). So when the user use the back button B and C will not show up, I've been trying the following:

Intent intent = new Intent(this, A.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); 
startActivity(intent);

But B and C are still showing up if I use the back button when I'm back in activity A. How can I avoid this?


E
Ev0lv3zz

Try adding FLAG_ACTIVITY_NEW_TASK as described in the docs for FLAG_ACTIVITY_CLEAR_TOP:

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.

So your code to launch A would be:

Intent intent = new Intent(this, A.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK); 
startActivity(intent);
CurrentActivity.this.finish(); // if the activity running has it's own context


// view.getContext().finish() for fragments etc.

Thanks but I've tried this. Still when I tap the back button after it shows C again. What can I be missing?
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_NEW_TASK);
doesn't work for me however calling finish() on source activity does what I needed to achieve
I had the same problem that this was not working. What fixed it for me was to call finish() after starting the new activity
I also added one more clear Intent intent = new Intent(SingUpActivity.this, LoginActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(intent); finish();
P
Philippe A
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);

With all respect to the CLEAR_TOP flag - this combination is the ONLY one that completely cleared the entire stack and made the new activity the only one in the app. Thank you!
What's the diff between this and the accepted answer?
Thanks, the difference with the accepted answer is that with this flag we dont need to call activity.finish
FLAG_ACTIVITY_CLEAR_TASK worked perfectly together with NEW_TASK
This should be the accepted answer. Thank you very much.
B
Bhunnu Baba

What about adding in manifests file for related activity :

android:noHistory="true"

to the activity definition of B and C ? They will not be added to the backstack. Not sure if that is what you want.


Be very careful while using this - If you are using login with FB or any similar sort of functionality
@Skynet Why? What are the problems associated with doing this?
When you pass control to FB for login from a page with nohistory as true, the FB app does not now where to land after loging the user in, in my case it was returning to the phone home screen and I almost lost my job!
This does not let an activity addded to backstack....this is not correct solution.
Exactly i am looking for
G
Geng Jiawen

This bothers me for a long time .Finally I worked it out by doing this:

In fragment,use:

Intent intent = new Intent(view.getContext(), A.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK); 
startActivity(intent);

In Activity,use(add one more intent flag Intent.FLAG_ACTIVITY_CLEAR_TASK compared to fragment):

Intent intent = new Intent(this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

If you are using androidannotations, you have to add: Intent.FLAG_ACTIVITY_CLEAR_TASK
Activity solutioin worked fine for me. Although I think with API 16 the solution from Daniel Schuler is easier.
Thank you yosafatade, that was what I was missing!
D
Daniel Schuler

Starting in API 16 (Jelly Bean), you can just call finishAffinity().

Now you can also call ActivityCompat.finishAffinity(Activity activity) with the compatibility library.

Be sure to set taskAffinity in the manifest to a package name unique to that group of activities.

See for more info:
http://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#finishAffinity%28android.app.Activity%29


Realy userful and easy solution if you are alread on API 16. Worked for me!
reminder: this will only work for activities in that share the same taskAffinity name
this only work if you have just one activity in the history.
J
Joseph Earl

Add android:launchMode="singleTop" to the activity element in your manifest for Activity A Then use intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP) and intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK) when starting Activity A

This means that when Activity A is launched, all tasks on top of it are cleared so that A is top. A new back stack is created with A at the root, and using singleTop ensures you only ever launch A once (since A is now on top due to ..._CLEAR_TOP).


Yes. this is what I'm using now but that doesn't do it. Still C shows up when I hit the back button.
Odd, I used that in a project and it works fine... pressing back takes me to the home screen. Perhaps there's something else going on. Could you post your manifest?
I restarted the emulator and now it seems to be working just like you said. Thanks a lot for your help!
singleTop should have nothing to do with clearing the stack.
c
cagdasalagoz

Try using

intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

and not

intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

This works. My assumption was that using setFlags would replace all default set flags but this was not the case
J
Jaydeep purohit

If your application has minimum sdk version 16 then you can use finishAffinity()

Finish this activity as well as all activities immediately below it in the current task that have the same affinity.

This is work for me In Top Payment screen remove all back-stack activits,

 @Override
public void onBackPressed() {
         finishAffinity();
        startActivity(new Intent(PaymentDoneActivity.this,Home.class));
    } 

http://developer.android.com/reference/android/app/Activity.html#finishAffinity%28%29


C
Community

As per Wakka in Removing an activity from the history stack...

Add android:noHistory="true" attribute to your <activity> in the AndroidManifest.xml like this:

    <activity android:name=".MyActivity"
        android:noHistory="true">
    </activity>

B
Biswajit_86

For future research, try this code.

Intent intent = new Intent(context, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
finish();

These flags finally worked for me. What I did was I started the same Activity I was in with these flags and a boolean extra EXIT=true. The in onCreate() I checked the launch parameters for EXIT and called finish() if it was set true. That's a lot of hassle just to close your own app.
b
baswaraj

Use finishAffinity(); in task C when starting task A to clear backstack activities.


only this answer works for me. Intent.FLAG_ACTIVITY_CLEAR_TOP and Intent.FLAG_ACTIVITY_NEW_TASK are not required
F
Firzan Shaikh
Use finishAffinity() to clear all backstack with existing one.

Suppose, Activities A, B and C are in stack, and finishAffinity(); is called in Activity C, 

    - Activity B will be finished / removing from stack.
    - Activity A will be finished / removing from stack.
    - Activity C will finished / removing from stack.

M
Manaus

Use this code for starting a new Activity and close or destroy all other activity stack or back stack.

Intent intent = new Intent(this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);

A
Adeel

I found an interesting solution which might help. I did this in my onBackPressed() method.

finishAffinity();
finish();

FinishAffinity removes the connection of the existing activity to its stack. And then finish helps you exit that activity. Which will eventually exit the application.


E
Exigente05

In kotlin it is almost same like java. Only | symbol is replaced by or text. So, it is written like-

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK or Intent.FLAG_ACTIVITY_NEW_TASK)

i
ianjoyner

I found the answers here a little misleading because the code in the original question seems to work fine for me?

With A being the root activity, starting it from B or C only with FLAG_ACTIVITY_CLEAR_TOP does remove B and C from the back stack.


c
cagdasalagoz

It sounds to me like you need to start Activity C from Activity B by using startActivityForResult(). When you click a button in Activity C, call setResult(RESULT_OK) and finish() so Activity C is ended. In Activity B, you could have the onActivityResult() respond by also calling finish() on itself, and you'd then be taken back to Activity A.


Yes, but if there are 42 activities between A and C, this will be rather tedious. The flag FLAG_ACTIVITY_CLEAR_TOP is supposed to do directly what the OP want.
This would be a less than optimal way of achieving what the OP wants, and as @Guillaume said, it would require code in all of the activities between the root and the top of the stack.
Duly noted. These are flags I need to learn about apparently.
G
Gibolt

Advanced, Reuseable Kotlin:

You can set the flag directly using setter method. In Kotlin or is the replacement for the Java bitwise or |.

intent.flags = FLAG_ACTIVITY_NEW_TASK or FLAG_ACTIVITY_CLEAR_TASK

If use this more than once, create an Intent extension function

fun Intent.clearStack() {
    flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
}

You can then directly call this function before starting the intent

intent.clearStack()

If you need the option to add additional flags in other situations, add an optional param to the extension function.

fun Intent.clearStack(additionalFlags: Int = 0) {
    flags = additionalFlags or Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
}

c
cagdasalagoz

I tried all solutions and none worked individually for me. My Solution is :

Declare Activity A as SingleTop by using [android:launchMode="singleTop"] in Android manifest.

Now add the following flags while launching A from anywhere. It will clear the stack.

Intent in = new Intent(mContext, A.class);
in.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK );
startActivity(in);
finish();

c
cagdasalagoz

Intent.FLAG_ACTIVITY_CLEAR_TOP will not work in this case. Please use (Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK)

For more detail please check out this documentation.


s
stevyhacker

Kotlin example:

      val intent = Intent(this@LoginActivity, MainActivity::class.java)
      intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_NEW_TASK
      startActivity(intent)
      finish()

A
Abhijeet

logout.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK); logout.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);


M
Mujeeb Rahaman T
 intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);

M
Mohamed Mo'nes

for me adding Intent.FLAG_ACTIVITY_CLEAR_TASK solved the problem

Intent i = new Intent(SettingsActivity.this, StartPage.class);
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP  | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
                startActivity(i);
finish();

c
cagdasalagoz

You can use this example to call your Activity A from Activity C

Intent loout = new Intent(context, LoginActivity.class); loout.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK); context.startActivity(loout);


A
Arnaud

you wont get any activity pressing back button after that :

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK | 
Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
finishAffinity();
finish();

j
james

In addition to FLAG_ACTIVITY_CLEAR_TOP, you may try adding Intent.FLAG_ACTIVITY_SINGLE_TOP as well:

intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);


That would only affect the activity at the top of the stack, not the root of it.
S
Sathesh

The given code works correctly. I have tried in the Application Life Cycle sample.

I haven't got B and C in the back stack after starting activity A with flag, FLAG_ACTIVITY_CLEAR_TOP


S
Swap-IOS-Android

i called activity_name.this.finish() after starting new intent and it worked for me.

I tried "FLAG_ACTIVITY_CLEAR_TOP" and "FLAG_ACTIVITY_NEW_TASK"

But it won't work for me... I am not suggesting this solution for use but if setting flag won't work for you than you can try this..But still i recommend don't use it


A
Arun Sharma

Add NO History Flag in the intent.

In activity B, start the activity C as below >>>>>>

Intent intent = new Intent(this, C.class);
intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NO_HISTORY); 
startActivity(intent);
finish();