Android : Ringing call state is not work after Received 1st call android

i'have confuse about my code. I'm open activity it the time of Incoming Call/ Missed Call. But its open only 1st time till the received call. after receiving 1st call Not work Ringing state.

switch (state) {
    case TelephonyManager.CALL_STATE_IDLE:

            Log.v("idle state", "CALL_STATE_IDLE");
            // CALL_STATE_IDLE;


            if (ring == true && callReceived == false && CheckMissCall.isRunning== false) {

                Log.v("missed call", "Missed call from : " + incomingNumber);
                if(CheckMissCall.isShown)
                {
                    c.stopService(new Intent(c, Unlock_hud.class));

                }               
            flag = true;
            if (prefs.getBoolean("main_state", true))
            {
                Intent inter = new Intent(c, MissCall.class);
                inter.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                inter.putExtra("CellNumber", incomingNumber);
                c.startActivity(inter);

            }               
        }
            if(ring == true && callReceived == true && CheckMissCall.isReject == true)
            {
                Intent inter = new Intent(c, callLog.class);
                inter.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);          
                c.startActivity(inter); 
            }
        break;


    case TelephonyManager.CALL_STATE_OFFHOOK:
            // CALL_STATE_OFFHOOK;
            callReceived = true;
            Log.v("call received", "CALL_STATE_OFFHOOK  " + incomingNumber);
            break;


    case TelephonyManager.CALL_STATE_RINGING:
            ring = true;

            // CALL_STATE_RINGING
            Log.v("call ringing", "CALL_STATE_RINGING  " + incomingNumber);
            Log.d("flags", "flags: " + flag);
            if (flag ) {

                //cut = true;
                //flag = false;
                CheckMissCall call = new CheckMissCall(c);
                call.setName(incomingNumber);
                call.setNumber4Sms(incomingNumber);
                call.setContactPhoto();

                Log.d("main", "state ringing");
                prefs = PreferenceManager.getDefaultSharedPreferences(c);

                if (!prefs.getBoolean("main_state", false)) 
                {

                    return;
                }
                /*  if (!isScreenOn && CheckMissCall.isRunning) {

                    return;
                }*/
                if (CheckMissCall.isRunning) {

                    return;
                }
                else {
                    Log.d("main", "EEEEEEEEEEEEEEEE:  Unlock hud");
                    Intent in = new Intent(c, Unlock_hud.class);
                    in.setFlags(Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP);
                    c.startService(in);

                    // c.stopService(new Intent(c, Unlock_hud.class));
                }
            }
            break;

Now what i have to do ..??