Start Activity and Bring it to Front

Question

I have a service that once it completes a task it launches an intent to start an activity from my application. Like this:

Intent i = new Intent(MyService.this, MyActivityToBringToFront.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//i.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
//i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
//i.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(i); 

This service can be running even after my application has been closed. When this is the case and my application is closed I need it to bring the activity to the front of whatever the user is currently doing. So if the user is in a different app I need my activity to pop up in front. Is this possible. None of the flags had any effect. Basically I need it to be like the system phone application. When you get a phone call it always brings the phone to the front. How can I do this? Thanks!

Answer 1

First of all you need to keep context in memory to make intent's.

Secondary you need a mechanism that can re-obtaining your context every 24 hours because usually context stay alive in 24 hours.

After.

Launching Activity from service :

Intent dialogIntent = new Intent(getBaseContext(), myActivity.class);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplication().startActivity(dialogIntent);

source : https://stackoverflow.com/a/3607934/2956344

To push activity on top add

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);

Answer 2

Intent i = new Intent();
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.setAction("android.intent.action.VIEW");

i.setComponent(ComponentName.unflattenFromString("com.example.package/com.example.package.activityName"));

startActivity(i);

Answer 3

Intent i = new Intent(MyService.this, MyActivityToBringToFront.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TOP);
context.startActivity( i);

And API reference is

If set, and the activity being launched is already running in the current task, then instead of launching a new instance of that activity, all of the other activities on top of it will be closed and this Intent will be delivered to the (now on top) old activity as a new Intent.

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.

The currently running instance of activity B in the above example will either receive the new intent you are starting here in its onNewIntent() method, or be itself finished and restarted with the new intent. 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().

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.

Answer 4

launching an activity from a service isn't always a good idea. You may want to use notification for that. If the user clicks on the notification, thats the time you show the Activity.