code

package com.example.edson.terminatorapp;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.le.ScanSettings;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.UUID;
import com.polidea.rxandroidble.RxBleClient;
import com.polidea.rxandroidble.RxBleConnection;
import com.polidea.rxandroidble.RxBleDevice;
import com.polidea.rxandroidble.internal.RxBleLog;

import org.w3c.dom.Text;

import rx.Subscription;

public class MainActivity extends AppCompatActivity {
    RxBleClient rxBleClient;
    Boolean IsConnected = false;
    String macAddress;
    String name;
    Button helloButton;
    Button scanButton;
    TextView macAddressText;
    Subscription scanSubscription;
    //String uuidCharacteristicValue = "0xA001";
    String uuidCharacteristicValue = "0000a001-0000-1000-8000-0080";
    //String uuidServiceValue = "0xA000";

    final UUID characteristicUuid = java.util.UUID.fromString(uuidCharacteristicValue);
    //final UUID serviceUuid = java.util.UUID.fromString(uuidServiceValue);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        rxBleClient = RxBleClient.create(this);
        helloButton = (Button) findViewById(R.id.helloButton);
        scanButton = (Button) findViewById(R.id.scanButton);
        macAddressText = (TextView)findViewById(R.id.macAddressText);
        scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    Log.e("MainActivity", "Scanning");
                    scanSubscription = rxBleClient.scanBleDevices().subscribe(
                            rxBleScanResult -> {
                                // Process scan result here.
                                name = rxBleScanResult.getBleDevice().getName();
                                Log.e("MainActivity","Name :"+ name);
                                if(name.equals("Terminator")) { //TODO REFACTOR
                                    Log.e("MainActivity","Found terminator!");
                                    macAddress = rxBleScanResult.getBleDevice().getMacAddress();
                                    macAddressText.setText("Connected to: " + macAddress);
                                    scanSubscription.unsubscribe();
                                }
                            },
                            throwable -> {
                                Log.e("MainActivity","ERROR :"+ throwable.getMessage());
                            }
                    );
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
        helloButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v) {
                try{
                    Log.e("MainActivity", "Connecting");
                    RxBleDevice device = rxBleClient.getBleDevice(macAddress);
                    RxBleClient.setLogLevel(RxBleLog.DEBUG);
                    Subscription subscription = device.establishConnection(getApplicationContext(), false)
                            .flatMap(rxBleConnection -> rxBleConnection.setupNotification(characteristicUuid))
                            .doOnNext(notificationObservable -> {
                                // Notification has been set up
                                Log.e("MainActivity", "Bytes: " + notificationObservable);
                            })
                            .flatMap(notificationObservable -> notificationObservable) // <-- Notification has been set up, now observe value changes.
                            .subscribe(
                                    bytes -> {
                                        // Given characteristic has been changes, here is the value.
                                        Log.e("MainActivity", "Bytes: " + bytes);
                                    },
                                    throwable -> {
                                        // Handle an error here.
                                    }
                            );

//                            //.flatMap(RxBleConnection::discoverServices)
//                            .flatMap(rxBleConnection -> rxBleConnection.readCharacteristic(characteristicUuid))
//                            .subscribe(characteristicValue -> {
//                                Log.e("MainActivity", "CharacteristicValue: " + characteristicValue);
//                            },
//                              throwable -> {
//                                  Log.e("MainActivity", "Any error:" + throwable.getMessage());
//                              });
//                            .subscribe(
//                                    rxBleConnection ->  {
//                                        // All GATT operations are done through the rxBleConnection.
//                                        Log.e("MainActivity", "GATT Operations: " + rxBleConnection.discoverServices());
//                                    },
//                                    throwable -> {
//                                        // Handle an error here.
//                                        Log.e("MainActivity", "Any error");
//                                    }
//                            );
                } catch (Exception e){
                    e.printStackTrace();
                }
            }
        });
    }
}