Android: Clear the back stack

Question

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?

Waddle

Answer 1

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.

Nat

Thanks but I've tried this. Still when I tap the back button after it shows C again. What can I be missing? – Waddle

How do you declare your activities in AndroidManifest.xml? – Nat

I've tried with android:launchMode="singleTop" but that didn't make any difference. I can't see what is wrong. So when you use this code and hit back button C will not show up? – Waddle

Are all the activities declared with the same taskAffinity? – Nat

Huh, this doesn't work for me either. It should... I'll look into it. – Nat

Try it with intent.addFlags(int), that made it work for me. I bet setFlags overrides the previous flags, so only NEW_TASK was getting added. – Nat

So irritating, I restarted the emulator and eclipse, cleaned the project and now it seems to be working just like you said. I mark this as the answer as this was the first one. – Waddle

Glad I could "help". Restarting Eclipse and the emulator tend to be near the top of my troubleshooting list. – Nat

I have been frustrated with this for a couple hours now, with NOTHING seeming to work. I just realized that I am using Action Bar Sherlock SherlockActivities and not normal Android activities. Could this have something to do with it? – Protoactinium

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_NEW_TASK); – Luthern

@Kyle I struggled with this as well, take a look at: https://mcmap.net/q/93650/-on-logout-clear-activity-history-stack-preventing-quot-back-quot-button-from-opening-logged-in-only-activities – Alexio

doesn't work for me however calling finish() on source activity does what I needed to achieve – Jeer

I had the same problem that this was not working. What fixed it for me was to call finish() after starting the new activity – Negotiation

@Arno Thank you! finish() did it. I would never have thought of it without your tip. – Biron

Use addFlags not setFlags, figured it out the hard way. Also added Intent.FLAG_ACTIVITY_NEW_TASK – Kike

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(); – Investigate

That's a good answer, but it may be replaced by without calling finish on current activity: Intent intent = new Intent(this, A.class); intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(intent); – Intercessor

Also, for APK21+ there is finishAndRemoveTask. – Jewett

Answer 2

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);

Probst

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! – Ial

What's the diff between this and the accepted answer? – Mirepoix

Thanks, the difference with the accepted answer is that with this flag we dont need to call activity.finish – Arse

With this setup, when I click back, it closes the app. – Orthopedics

FLAG_ACTIVITY_CLEAR_TASK worked perfectly together with NEW_TASK – Concurrent

This closes all activity in stack, WHAT I NEEDED. App closes on back press. – Beaty

Answer 3

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.

Carboni

Be very careful while using this - If you are using login with FB or any similar sort of functionality – Forbidden

@Skynet Why? What are the problems associated with doing this? – Baker

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! – Forbidden

This does not let an activity addded to backstack....this is not correct solution. – Resemble

Exactly i am looking for – Discombobulate

only this answer worked for me . because all of the sudden back button went to wrong activity . idk how . but this one . at least made me sure that no activity took place in stack – Pathogenic

Answer 4

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);

Ivie

If you are using androidannotations, you have to add: Intent.FLAG_ACTIVITY_CLEAR_TASK – Runt

Activity solutioin worked fine for me. Although I think with API 16 the solution from Daniel Schuler is easier. – Wrathful

Thank you yosafatade, that was what I was missing! – Tercentenary

Answer 5

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

Hepburn

Realy userful and easy solution if you are alread on API 16. Worked for me! – Wrathful

reminder: this will only work for activities in that share the same taskAffinity name – Chorion

this only work if you have just one activity in the history. – Tranquil

Answer 6

1. Add android:launchMode="singleTop" to the activity element in your manifest for Activity A
2. 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).

Genitive

Yes. this is what I'm using now but that doesn't do it. Still C shows up when I hit the back button. – Waddle

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? – Genitive

I restarted the emulator and now it seems to be working just like you said. Thanks a lot for your help! – Waddle

singleTop should have nothing to do with clearing the stack. – Frank

Answer 7

Try using

intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

and not

intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

Carissacarita

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

Answer 8

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

Colman

Answer 9

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.

Horthy

Answer 10

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>

Hordein

Answer 11

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();

Ordovician

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. – Sicyon

Answer 12

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

Dispense

only this answer works for me. Intent.FLAG_ACTIVITY_CLEAR_TOP and Intent.FLAG_ACTIVITY_NEW_TASK are not required – Hawkins

Answer 13

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);

Imminent

Answer 14

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.

Mezoff

Answer 15

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)

Passing

Answer 16

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
}

Starvation

Answer 17

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.

Tempest

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. – Illness

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. – Nat

Duly noted. These are flags I need to learn about apparently. – Tempest

Answer 18

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.

Jody

Answer 19

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.

Fiddlewood

Answer 20

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();

Resemble

Answer 21

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()

Heideheidegger

Answer 22

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

Mokas

Answer 23

 intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);

Roveover

Answer 24

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();

Master

Answer 25

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);

Excurved

Answer 26

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();

Bijection

Answer 27

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);

Legitimate

That would only affect the activity at the top of the stack, not the root of it. – Nat

Answer 28

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

Babbette

Answer 29

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

Viridity

Answer 30

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();

Schlicher

Answer 31

Either add this to your Activity B and Activity C

android:noHistory="true"

or Override onBackPressed function to avoid back pressing with a return.

@Override
public void onBackPressed() {
   return;
}

Quacksalver

Answer 32

In manifest

android:launchMode="singleTask"

and

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

Fluky

Answer 33

Use setFlags() method for clear back side opened all activity close and start yourActvity

Intent intent = new Intent(getApplicationContext(), yourActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);

Imminent

Answer 34

This worked for me with onBackPressed:

public void onBackPressed()
{
    Intent intent = new Intent(ImageUploadActivity.this, InputDataActivity.class);

    Intent myIntent = new Intent(this, ImageUploadActivity.class);
    myIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
   finish();
}

Dekameter

Answer 35

This is how I solved the problem:

private boolean clearHistoryBackStack = true;

@Override
public final void finish() {
    super.finish();

    if(clearHistoryBackStack)
        finishAffinity();
}

Pederasty

Answer 36

This code work for me in kotlin:

 val intent = Intent(this, MainActivity::class.java)
 intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_CLEAR_TASK or Intent.FLAG_ACTIVITY_NEW_TASK)
 startActivity(intent)
 finish()

Deel

Answer 37

Though this may be coming late. I ran into this same problem while trying to move from activity A -> B -> C -> D, then to B if D returns true, I wanted to clear activity D and C.

val intent = Intent(this, ActivityUpload::class.java)
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
startActivity(intent)

I got the solution as described in the documentation.

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.

Fitzpatrick

Answer 38

This is a really old answer and i didn't really found a proper solution to it, to the sole purpose of clearing the backStack, i decided to create my own backstack, which is not even a stack tbh, but it doesn't have to be, since we want to clear everything in it anyways;

Theres an overhead of handlind the backstack everytime, but it gave me the control i needed;

---

First Declare a public static List of Activities (or fragments, whatever you need);

public static ArrayList <Activity> backStack = new ArrayList<>();

And inside all other activity's onCreate method:

MainActivity.backStack.add(this);

And finally, when you want to clear the backstack, simply call:

public static void killBackStack () {
    for (Activity ac : backStack) {
        if (ac != null)
            ac.finish();
    }
}

Jahveh

Answer 39

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

Knitter