Open Android App by clicking on Notification

I use Google Cloud Messaging to send Notficitations to my app. If my app is in foreground i just want to silently call a methode in unity from my service, else i want to start my app by clicking on the notification. I googled and found out to determinate if my app runs in foreground with:

 public boolean isForeground(String myPackage){
         ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
          List< ActivityManager.RunningTaskInfo > runningTaskInfo = manager.getRunningTasks(1); 
 
              ComponentName componentInfo = runningTaskInfo.get(0).topActivity;
            if(componentInfo.getPackageName().equals(myPackage)) return true;
         return false;
         }

So, what do I need to pass as the myPackage parameter? A standard unity package parameter or acctually my package name? I know I can call methodes in Unity from Android with the UnityPlayer class But how can I start my app if its dont even running or putting in back into foreground if its in background?

Update: Just a little update: This methode dont work. It just returns true if myPackage equals the package of my class, and not unity, so in the end, I dont get any new infromation.