태스크에 있는 액티비티 띄우기

ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(Integer.MAX_VALUE);
if (!tasks.isEmpty()) {

    int tasksSize = tasks.size();

    for (int i = 0; i < tasksSize; i++) {

        ActivityManager.RunningTaskInfo taskinfo = tasks.get(i);

        if (taskinfo.topActivity.getPackageName().equals(getApplicationContext().getPackageName())) {
            am.moveTaskToFront(taskinfo.id, 0);
        }

    }

}