Android : Android : How to hide the Activity without using finish

I'am just calling an Activity from the BroadCastReceiver. So when the phone is Ringing it will show the Activty. My problem is when I use my application then if i get a call means then the current Activity is not hiding.

So I cannot see the calling screen and I cannot pick the call. Whatever the activity I have opened, Just I want to hide when the call is coming and again I want to show the same Activity.

Before that I have used finish method in the onReceive method. But if I use that then next time it is not calling the BroadCastReceiver.

Instead of this code what I can write to hide all my Activities.

@Override
public void onReceive(Context context, Intent intent) {
    LoginActivity.context.finish();
    MainAtivity.context.finish();
    ProjectActivity.context.finish();
    telephonyRegister(context,intent);
 }