Within Android, how do I start an activity or bring to front that activity if already on stack?

Question

So far I know start a new activity myActivity, as by the code below shows. But I don't want to open a second copy of the same class, if it's already open on the stack. So how do I check whether activities like the below exist on the stack, then if it exists bring it to front. If it doesn't, open a new activity like below

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

score 2 · Accepted Answer · answered Nov 18 '14 at 14:54

2

Use a flag in your intent when you want to start new Activity

http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_REORDER_TO_FRONT

Intent intent = new Intent(myActivity.this,
        myActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);

answered Nov 18 '14 at 14:54

Tomislav Novoselec

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Just to confirm, will that bring an activity to the front if it exists. But if it doesn't, create a new – Nov 18 '14 at 14:55
exactly. play with those flags a bit to see what kind of results you can get – Tomislav Novoselec Nov 18 '14 at 14:56
No, that still seems to create new items in the stack at times when one already exists – Nov 18 '14 at 15:45

score 0 · Answer 2 · answered Nov 18 '14 at 14:55

0

Intent intent = new Intent(myActivity.this,
        myActivity.class);
 intent .addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);

answered Nov 18 '14 at 14:55

Prem

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score 0 · Answer 3 · edited May 23 '17 at 11:44

It sounds like you might have several processes running or other instances of the Activity started through other calls to start the Activity.

You are probably needing to specify in the manifest either "singleInstance" or "singleTask" -

Android singleTask or singleInstance launch mode?

Word of caution - this may have some other unintended side effects. Just be sure to test it for different use-cases.

Within Android, how do I start an activity or bring to front that activity if already on stack?

3 Answers3