How to always return to same activity on back button?

Question

I have a main activity with a menu. The menu items lead to other activities. I am trying to implement it so that when I start a new activity from the menu, upon pressing the back button the app returns to the main activity regardless of how many other activities were previously opened.

I have tried to use the CLEAR_TOP flag but that doesn't do the trick.

menuItem.setOnClickListener(v -> {
        Intent i = new Intent(AppMenuActivity.this, SomeActivity.class);
        overridePendingTransition(0, 0);
        i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);
        resideMenu.closeMenu();
    });

Answer 1

From FLAG_ACTIVITY_CLEAR_TOP android documentation:

FLAG_ACTIVITY_CLEAR_TOP

public static final int FLAG_ACTIVITY_CLEAR_TOP

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().

What does it mean?

• If launch mode of your activity is "multiple/standard/default" AND you do not set FLAG_ACTIVITY_SINGLE_TOP in the same intent, then it will be finished and re-created.
• If launch mode of your activity is not "multiple/standard/default" OR you set FLAG_ACTIVITY_SINGLE_TOP in the same intent, then this Intent will be delivered to the current instance's onNewIntent().

Because your MainActivity has "default" launch mode and you do not set FLAG_ACTIVITY_SINGLE_TOP in the same intent, so it will be finished and re-created.

But you want users back to current instance of MainActivity, so you need to set FLAG_ACTIVITY_SINGLE_TOP in the same intent.

Just change your code from

i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

to

i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);