TextView won't update within handler

Question

I've tried to make an app that receives a String through Buetooth from Arduino.

Its format is "#100.23+123.12+90.45+101.20~, + is a separator between four double number, starts with # and ends with ~.

I've followed the tutorial here. Everything seems ok but mostly the four Textviews won't update with values as I have assigned for them.

This is the code that updates the Textview, it relies on the onCreate() function.

Sometimes it does update (rarely), and most the time it just doesn't change. Please help me with this, I have a little knowledge about android. Thanks

    sensorView0 = (TextView) findViewById(R.id.sensorView0);
    sensorView1 = (TextView) findViewById(R.id.sensorView1);
    sensorView2 = (TextView) findViewById(R.id.sensorView2);
    sensorView3 = (TextView) findViewById(R.id.sensorView3);
    //sensorView0.setText("Temp111111");
    bluetoothIn = new Handler() {
        public void handleMessage(android.os.Message msg) {
            if (msg.what == handlerState) {                                     //if message is what we want
                String readMessage = (String) msg.obj;                                                                // msg.arg1 = bytes from connect thread
                recDataString.append(readMessage);                                      //keep appending to string until ~

                int startOfLineIndex = recDataString.indexOf("#");
                int endOfLineIndex = recDataString.indexOf("~",startOfLineIndex);                    // determine the end-of-line
                if (endOfLineIndex > 0) {                                           // make sure there data before ~
                    String dataInPrint = recDataString.substring(startOfLineIndex, endOfLineIndex);    // extract string

                    if (dataInPrint.charAt(0) == '#')                             //if it starts with # we know it is what we are looking for
                    {
                        int startPos =1;
                        int endPos = dataInPrint.indexOf("+");
                        String sensor0 = dataInPrint.substring(startPos, endPos);             //get sensor value from string between indices 1-5
                        startPos =endPos +1;
                        endPos = dataInPrint.indexOf("+",endPos+1);
                        String sensor1 = dataInPrint.substring(startPos, endPos);            //same again...
                        startPos =endPos +1;
                        endPos = dataInPrint.indexOf("+",endPos+1);
                        String sensor2 = dataInPrint.substring(startPos, endPos);
                        startPos =endPos +1;
                        endPos = dataInPrint.indexOf("+",endPos+1);
                        String sensor3 = dataInPrint.substring(startPos, endPos);

                        sensorView0.setText(" Heart Rate = " + sensor0 + "bpm");    //update the textviews with sensor values
                        sensorView1.setText(" Blood = " + sensor1 + "V");
                        sensorView2.setText(" Sensor 2 Voltage = " + sensor2 + "V");
                        sensorView3.setText(" Sensor 3 Voltage = " + sensor3 + "V");

                    }
                    recDataString.delete(0, recDataString.length());                    //clear all string data

                    dataInPrint = " ";
                }
            }
        }
    };