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?

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.

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

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.

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);

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

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).

Try using

intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

and not

intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

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

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>

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();

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

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);

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.

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.

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)

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.

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.

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
}

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.

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();

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()

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

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

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();

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);

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);

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

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

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();

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;
}

In manifest

android:launchMode="singleTask"

and

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

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);

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();
}

This is how I solved the problem:

private boolean clearHistoryBackStack = true;

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

	if(clearHistoryBackStack)
		finishAffinity();
}

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()

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();

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.

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();
    }
}

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