Unable to connect to BLE device using NRF library

Question

Can anybody provide an simple example how to connect BLE device, Read and write data using NRF library.

https://github.com/NordicSemiconductor/Android-Scanner-Compat-Library https://github.com/NordicSemiconductor/Android-BLE-Library

What I have done.

1. I have used the scanner library and able to scan the devices.
2. Using Android-BLE-Library but not sure how to connect and write data to device and read data from it.

Tried to follow the https://github.com/NordicSemiconductor/Android-nRF-Blinky example but it's for LED on/OFF and in MVVM.

Want some example for connecting part in MVC.

public class MainActivity extends AppCompatActivity {
public final String TAG = "MainActivity";

Context mContext = null;
TextView data;
String text = "";
boolean isConnecting = false;
private final List<BluetoothDevice> mDevices = new ArrayList<>();
/** Flag set to true when scanner is active. */
private boolean mScanning;
private Handler mHandler;
private final static long SCAN_DURATION = 5000;

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

    mContext = this;

    final Button connect = findViewById(R.id.button);
    data = findViewById(R.id.data);
    mHandler = new Handler();

    connect.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                connectNow();
            }
        }
    });
}

private void connectNow() {
    if (mScanning) {
        // Extend scanning for some time more
        mHandler.removeCallbacks(mStopScanTask);
        mHandler.postDelayed(mStopScanTask, SCAN_DURATION);
        return;
    }

    BluetoothLeScannerCompat scanner = BluetoothLeScannerCompat.getScanner();
    ScanSettings settings = new ScanSettings.Builder()
            .setLegacy(false)
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setReportDelay(1000)
            .setPhy(ScanSettings.PHY_LE_ALL_SUPPORTED)
            .build();
    List<ScanFilter> filters = new ArrayList<>();
    ScanFilter filter = new ScanFilter.Builder().setDeviceAddress("00:0B:57:47:E1:7B").build();
    filters.add(filter);
    scanner.startScan(filters, settings, mScanCallback);

    // Setup timer that will stop scanning
    mHandler.postDelayed(mStopScanTask, SCAN_DURATION);
    mScanning = true;
}

public void stopLeScan() {
    if (!mScanning)
        return;

    final BluetoothLeScannerCompat scanner = BluetoothLeScannerCompat.getScanner();
    scanner.stopScan(mScanCallback);

    mHandler.removeCallbacks(mStopScanTask);
    mScanning = false;
}

private Runnable mStopScanTask = new Runnable() {
    @Override
    public void run() {
        MainActivity.this.stopLeScan();
    }
};

private ScanCallback mScanCallback = new ScanCallback() {
    @Override
    public void onScanResult(final int callbackType, final ScanResult result) {
        // empty
        Log.e("onScanResult","onScanResult : " + result.getDevice().getName() + " " + result.getDevice().getAddress());
    }

    @Override
    public void onBatchScanResults(final List<ScanResult> results) {
        final int size = mDevices.size();
        BluetoothDevice device;
        for (final ScanResult result : results) {
            device = result.getDevice();
            if (!mDevices.contains(device))
                mDevices.add(device);

            if (size != mDevices.size()) {
                data.setText(data.getText() +"\n"+ device.getAddress());
            }
        }

    }

    @Override
    public void onScanFailed(final int errorCode) {
        // empty
    }
};

@Override
protected void onPause() {
    super.onPause();
    stopLeScan();
}

}