Main Activity Write The code
public static boolean isinFG = false;

public void onPause() {
super.onPause();
isinFG = false;
}

public void onResume() {
super.onResume();
isinFG = true;
}

public void onDestroy() {
super.onDestroy();
isinFG = false;
}
}

Calss GCMIntentService

add line
if (PushPlugin.isInForeground() && natuurhuisje.isinFG) {
instead of if (PushPlugin.isInForeground()) {