How to get current foreground activity context in android?

Issue

Whenever my broadcast is executed I want to show alert to foreground activity.

Solution

Knowing that ActivityManager manages Activity, so we can gain information from ActivityManager. We get the current foreground running Activity by

ActivityManager am = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
ComponentName cn = am.getRunningTasks(1).get(0).topActivity;

UPDATE 2018/10/03
getRunningTasks() is DEPRECATED. see the solutions below.

This method was deprecated in API level 21. As of Build.VERSION_CODES.LOLLIPOP, this method is no longer available to third party applications: the introduction of document-centric recents means it can leak person information to the caller. For backwards compatibility, it will still return a small subset of its data: at least the caller's own tasks, and possibly some other tasks such as home that are known to not be sensitive.

Answered By - KAlO2