Android: Presenting a notification during a call?

Question

I have a broadcast receiver that listens to incoming calls. And I want to tweak the incoming call screen. Right now I can present toasts and add notifications to the notification bar (BTW the user can't pull it down because the screen is locked, before accepting the call, which kinda sucks). I tried to show an alert but it crashed - is it not allowed? Is there a way for the code in the broadcast receiver to do other things, like change the avatar of the caller or give it a name (even if it doesn't exist in the contacts). Let's just say my broadcast receiver intercepts a call - can it add the phone number and a custom avatar to the contacts, so that they will immediately be presented in the call screen?

What do you think?

---

Edit

I have tested vendor's code, and it worked, but it is not safe to change the UI from a background thread, so I tried to tweak his code a bit to make it thread safe but the toast doesn't appear for some reason. What do you think?

private Handler handler = new Handler();

    private void showToast() { 
        Thread thread = new Thread(null, doBackgroundThreadProcessing, "Background");
        thread.start();
    }

    private Runnable doBackgroundThreadProcessing = new Runnable() { 
        public void run() {
            backgroundThreadProcessing();
        } 
    };

    private void backgroundThreadProcessing() {
        handler.post(new Runnable() {
            public void run() { 
                int count = 0;
                try{
                    while (count < 10) {
                        toast.show();
                        Thread.sleep(1850);
                        count++;

                    }
                }
                catch(Exception e){

                    Log.e("LongToast", "", e);
                }
            } 
        });
    }