How to make sure that one android Activity resides in backstack only once

Question

Lets suppose activities(A,B,C) are opened in following sequence:

A -> B -> A -> C-> A

Now in normal case the activity backstack will look

| A |
| C |
| A |
| B |
| A |

Is there any way I can make sure that Activity A resides in the backstack only once? Or in other words backstack look like:

| A |
| C |
| B |

EDIT : I want that new instance of activity is launched every time, and all previous instances are removed from stack. Is it even possible using built in schemes?

Answer 1

You need to set android:launchMode="singleTask" or android:launchMode="singleInstance" for each activity in manifest.

Answer 2

If you want A to still be at the beginning then it sounds like you want to launch B and C as activities for results. See Activity.startActivityForResult

That way, the original activity A will launch B and C and when B and C exit they will return to the original A.

Otherwise, If you want A to go to the top NickT has the right answer.

Answer 3

android:launchMode in your manifest may help:

http://developer.android.com/guide/topics/manifest/activity-element.html#lmode

It's kind of geared to the main activity of your application though, not to arbitrary activities in your stack.

Edit: see NickT's answer, which i have upvoted :)

Answer 4

It sounds like you want to make use of the intent flag FLAG_ACTIVITY_REORDER_TO_FRONT