I'm currently working on an android app to control Bluetooth devices but no available devices show up even though I can find them from the built-in settings>bluetooth menu.
I initially followed the android starter sample out of the box, but couldn't make it work. I then came across several similar posts and tried those as well, but still couldn't make it work. This is my code so far: ```
public class MainActivity extends AppCompatActivity {
private static final int REQUEST_LOCATION_BT = 3;
private static final int REQUEST_ENABLE_BT = 2;
private BluetoothAdapter bluetoothAdapter;
private ArrayList<String> deviceList;
private ActivityMainBinding binding;
private ArrayAdapter<String> listAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
requiredSetup();
setupListView();
}
private void setupListView() {
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
deviceList = new ArrayList<>();
if (pairedDevices.size() > 0) {
// There are paired devices. Get the name and address of each paired device.
for (BluetoothDevice device : pairedDevices) {
deviceList.add(device.getName());
//String deviceHardwareAddress = device.getAddress(); // MAC address
}
}
listAdapter = new ArrayAdapter<>(this,
android.R.layout.simple_list_item_1, deviceList);
binding.listView.setAdapter(listAdapter);
}
private void requiredSetup() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
if (ContextCompat.checkSelfPermission(getApplicationContext(),
Manifest.permission.ACCESS_BACKGROUND_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(
MainActivity.this,
new String[]{Manifest.permission.ACCESS_BACKGROUND_LOCATION},
REQUEST_LOCATION_BT);
}
}
// checking if device supports bluetooth
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
// Device doesn't support Bluetooth
Toast.makeText(this, "Device doesnt support bluetooth", Toast.LENGTH_SHORT).show();
return;
}
// enabling bluetooth if disabled
if (!bluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_ENABLE_BT && resultCode == RESULT_OK) {
Toast.makeText(this, "Bluetooth enabled", Toast.LENGTH_SHORT).show();
} else if (requestCode == REQUEST_ENABLE_BT && resultCode == RESULT_CANCELED) {
Toast.makeText(this, "App requires bluetooth to function", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
if (requestCode == REQUEST_LOCATION_BT) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// Permission granted, yay! Start the Bluetooth device scan.
startScan();
} else {
// Alert the user that this application requires the location permission to perform the scan.
Toast.makeText(this, "Requires location permission to work", Toast.LENGTH_SHORT).show();
}
}
}
/**
* initializes device discovery. The list of devices are sent to the broadcast receiver
* The discovery process usually involves an inquiry scan of about 12 seconds,
* followed by a page scan of each device found to retrieve its Bluetooth name.
*/
private void startScan() {
// If we're already discovering, stop it
if (bluetoothAdapter.isDiscovering()) {
Toast.makeText(this, "stopping discovery", Toast.LENGTH_SHORT).show();
bluetoothAdapter.cancelDiscovery();
} else {
try {
// Register for broadcasts when a device is discovered
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
this.registerReceiver(mReceiver, filter);
// Request discover from BluetoothAdapter
bluetoothAdapter.startDiscovery();
binding.progressBar.setVisibility(View.VISIBLE);
} catch (IllegalArgumentException e) {
e.printStackTrace();
Toast.makeText(this, "receivers not registered", Toast.LENGTH_SHORT).show();
}
}
}
/**
* @param view the button view that is pressed and the scanning begins
*/
public void searchDevices(View view) {
// checking if location permissions enabled
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_LOCATION_BT);
} else {
startScan();
}
}
/**
* The BroadcastReceiver that listens for discovered devices and changes the title when
* discovery is finished
*/
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
Toast.makeText(getApplicationContext(), "reeiver working", Toast.LENGTH_SHORT).show();
// When discovery finds a device
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Get the BluetoothDevice object from the Intent
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// If it's already paired, skip it, because it's been listed already
if (device != null && device.getBondState() != BluetoothDevice.BOND_BONDED) {
listAdapter.add(device.getName() + "\n" + device.getAddress());
Log.i("NEW DEVICE", device.getName());
listAdapter.notifyDataSetChanged();
}
// When discovery is finished, change the Activity title
} else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
//setProgressBarIndeterminateVisibility(false);
//setTitle(R.string.select_device);
binding.progressBar.setVisibility(View.INVISIBLE);
if (listAdapter.getCount() == 0) {
Toast.makeText(context, "no devices found", Toast.LENGTH_SHORT).show();
}
} else if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
Toast.makeText(context, "Bluetooth state changed", Toast.LENGTH_SHORT).show();
} else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
Toast.makeText(context, "Discovery started", Toast.LENGTH_SHORT).show();
}
}
};
@Override
protected void onDestroy() {
super.onDestroy();
// Make sure we're not doing discovery anymore
if (bluetoothAdapter != null) {
bluetoothAdapter.cancelDiscovery();
}
// Unregister broadcast listeners
this.unregisterReceiver(mReceiver);
}}
This is my manifest permissions:
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
This is my repository. It would be very helpful if anyone could shed some light here.
