null pointer on bluetooth isEnable

[Amirhgh74]

I am getting nullPointer on the first line you wrote if (!bluetooth.isEnable) saying that bluetooth adapter is null , what should I do ?

[omaraflak]

bluetooth.onStart() method should be called first.

[Amirhgh74]

that was fixed thanks but I think I'm missing something is there any way I can see the sample application code for scanning and paring ?

the problem is when I start scanning , after a while onDiscoverFinished is called and no device is found but the sample works correctly

[omaraflak]

Great. Yes you can, the sample code is here :

https://github.com/OmarAflak/Bluetooth-Library/tree/master/app

More specifically here :

https://github.com/OmarAflak/Bluetooth-Library/blob/master/app/src/main/java/me/aflak/libraries/ui/scan/interactor/ScanInteractorImpl.java

You have to handle onDeviceFound(), it is called every time a device is discovered.

[Amirhgh74]

I have done what is needed I think here is my onCreate function where I'm testing things

`if (!bluetooth.isEnabled()){ bluetooth.enable(); }

    bluetooth.setBluetoothCallback(new BluetoothCallback() {
        @Override
        public void onBluetoothTurningOn() {}

        @Override
        public void onBluetoothOn() {
            Log.e("amir" , "bluetooth is turned on !");
        }

        @Override
        public void onBluetoothTurningOff() {}

        @Override
        public void onBluetoothOff() {}

        @Override
        public void onUserDeniedActivation() {
            // when using bluetooth.showEnableDialog()
            // you will also have to call bluetooth.onActivityResult()
        }
    });

    bluetooth.setDiscoveryCallback(new DiscoveryCallback() {
        @Override public void onDiscoveryStarted() {
            Log.e("amir" , "start discovery");
        }
        @Override public void onDiscoveryFinished() {
            Log.e("amir" , "finished discovery");
        }
        @Override public void onDeviceFound(BluetoothDevice device) {
            Log.e("amir" , "we have new device : " + device.getName());
        }
        @Override public void onDevicePaired(BluetoothDevice device) {}
        @Override public void onDeviceUnpaired(BluetoothDevice device) {}
        @Override public void onError(String message) {

            Log.e("amir" , message);

        }
    });

    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            bluetooth.startScanning();
        }
    }, 1000);`

when I start scanning, start discovery and finish discovery is logged correctly but no log for finding devices

[omaraflak]

This is a working example, you just need to request the permissions if not granted :

public class MainActivity extends AppCompatActivity implements BluetoothCallback, DiscoveryCallback {
    private Bluetooth bluetooth;

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

        bluetooth = new Bluetooth(this);
        bluetooth.setBluetoothCallback(this);
        bluetooth.setDiscoveryCallback(this);
    }

    @Override
    protected void onStart() {
        super.onStart();
        if(hasPermissions()){
            bluetooth.onStart();
            bluetooth.enable();
            bluetooth.startScanning();
        }
        else{
            // request permissions...
        }
    }

    boolean hasPermissions(){
        return
            ContextCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH) == PackageManager.PERMISSION_GRANTED &&
            ContextCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH_ADMIN) == PackageManager.PERMISSION_GRANTED &&
            ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED;
    }

    @Override public void onBluetoothTurningOn() {}

    @Override
    public void onBluetoothOn() {
        Log.d(getClass().getSimpleName(), "Bluetooth on");
    }

    @Override public void onBluetoothTurningOff() {}
    @Override public void onBluetoothOff() {}
    @Override public void onUserDeniedActivation() {}

    @Override
    public void onDiscoveryStarted() {
        Log.d(getClass().getSimpleName(), "scanning...");
    }

    @Override
    public void onDiscoveryFinished() {
        Log.d(getClass().getSimpleName(), "scanning finished.");
    }

    @Override
    public void onDeviceFound(BluetoothDevice device) {
        Log.d(getClass().getSimpleName(), "["+device.getAddress()+"] : "+device.getName());
    }

    @Override public void onDevicePaired(BluetoothDevice device) {}
    @Override public void onDeviceUnpaired(BluetoothDevice device) {}
    @Override public void onError(String message) {}
}

[Amirhgh74]

thanks for your help i was finally able to get it to work , but i have one more issue , when i use connect to device function after pairing with a device, nothing will get called just this line will be logged in logcat getBluetoothService() called with no BluetoothManagerCallback i searched and found that this is not an error its just a warning but i dont get any error on connection and my log in onDeviceConnected function wont get called either how can i get the status to check if im connected to the device ?

[HosseinBabriani]

Hello omar . how can i use DeviceCallback and receive message from Bluetooth?

[HosseinBabriani]

Hi how to use (Listen on Bluetooth socket DeviceCallback) inside fragment?