public class steuerung_Radarfeld extends AppCompatActivity {

    private BluetoothAdapter mBTAdapter;

    String address;
    String name;

    SimpleDateFormat dateFormat = new SimpleDateFormat("hh:mm:ss",Locale.GERMANY);
    String datum_Zeit;

    EditText multiliner;

    public String mac;
    private Handler mHandler;
    private ConnectedThread mConnectedThread;
    private BluetoothSocket mBTSocket = null;

    private static final UUID BTMODULEUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
    public String readMessage;

    private final static int MESSAGE_READ = 2;
    private final static int CONNECTING_STATUS = 3;

	//Ist die Variable, welche der App sagt, wann sie wieder Daten senden darf (wenn busy = false darf sie)
	boolean busy = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.radarfeld);

		//Text View in Form eines Multiline-Textviews
        multiliner = (EditText) findViewById(R.id.editText4);

        mBTAdapter = BluetoothAdapter.getDefaultAdapter();
		
		//MAC wird dem Intent mitgeliefert
        Intent intn = getIntent();
        mac = intn.getStringExtra("MAC");
        address = mac.substring(mac.length() - 17);
        name = mac.substring(0,mac.length() - 17);
        data();

        mHandler = new Handler(){
            public void handleMessage(Message msg){
                if(msg.what == MESSAGE_READ) {
                    readMessage = " ";
                    readMessage = new String((byte[]) msg.obj, 0,msg.arg1);

                    gibaus("Msg1: " + readMessage);
					//Von "XTE" werden X und E abgeschnitten, da sie nur quasi als Prüfsumme gelten.
                    readMessage = ueberpruefungmessage(readMessage);
                    gibaus("Msg2: " + readMessage);

					//Keine Datensendung von der App darf erfolgen
                    if (readMessage == "Y"){
                        busy = true;
                    }

					//Datensendung von der App darf erfolgen
                    if (readMessage == "T"){
                        busy = false;
                    }


                }

            }
        };
    }


    private String ueberpruefungmessage(String response){
        String erg = "";

        int laenge = 0;
        int posX = -1;
        int posY = -1;


        laenge = response.length();
        posX = response.indexOf('X');
        posY = response.indexOf('E');

        gibaus(String.valueOf(laenge));
        gibaus(String.valueOf(posX));
        gibaus(String.valueOf(posY));

        if (posX == 0 && posY == (laenge - 1)){
            erg = response.substring(posX + 1,posY);
        } else {
            erg = "Fehler in der Übertragung";
			// Fehler erscheint bei der fehlerhaften Übertragung
        }

        return erg;
    }


	//Ausgabe im Textview
    private void gibaus(String eg){
        datum_Zeit = dateFormat.format(new java.util.Date());
        multiliner.append(datum_Zeit + " : " + eg + "\n");
    }


    public void data(){

        new Thread()
        {
            public void run() {
                boolean fail = false;

                BluetoothDevice device = mBTAdapter.getRemoteDevice(address);

                try {
                    mBTSocket = createBluetoothSocket(device);
                } catch (IOException e) {
                    fail = true;
                    Toast.makeText(getBaseContext(), "Socket creation failed", Toast.LENGTH_SHORT).show();
                }
                try {
                    mBTSocket.connect();
                } catch (IOException e) {
                    try {
                        fail = true;
                        mBTSocket.close();
                        mHandler.obtainMessage(CONNECTING_STATUS, -1, -1)
                                .sendToTarget();
                    } catch (IOException e2) {
                        Toast.makeText(getBaseContext(), "Socket creation failed", Toast.LENGTH_SHORT).show();
                    }
                }
                if(!fail) {
                    mConnectedThread = new ConnectedThread(mBTSocket);
                    mConnectedThread.start();

                    mHandler.obtainMessage(CONNECTING_STATUS, 1, -1, name)
                            .sendToTarget();
                }
            }
        }.start();

    }

    private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
        return  device.createRfcommSocketToServiceRecord(BTMODULEUUID);
    }

    private class ConnectedThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            mmSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) { }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;
        }

		//Lesen der Daten, welche vom Arduino kommen
        public void run() {

            int bytes;
            while (true) {
                try {
                    bytes = mmInStream.available();

                    if(bytes != 0) {
                        bytes = mmInStream.available(); 
                        byte[] buffer = new byte[bytes];  
                        bytes = mmInStream.read(buffer, 0, bytes); 
                        mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
                                .sendToTarget(); 
                    }
                } catch (IOException e) {
                    e.printStackTrace();

                    break;
                }
            }
        }
    }
}