I want to enable/disable bluetooth through the program. I have the following code.
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
But this code is not working in SDK 1.5. How can I make it work?
Here is a bit more robust way of doing this, also handling the return values of enable()\disable() methods:
public static boolean setBluetooth(boolean enable) {
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
boolean isEnabled = bluetoothAdapter.isEnabled();
if (enable && !isEnabled) {
return bluetoothAdapter.enable();
}
else if(!enable && isEnabled) {
return bluetoothAdapter.disable();
}
// No need to change bluetooth state
return true;
}
And add the following permissions into your manifest file:
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
But remember these important points:
This is an asynchronous call: it will return immediately, and clients should listen for ACTION_STATE_CHANGED to be notified of subsequent adapter state changes. If this call returns true, then the adapter state will immediately transition from STATE_OFF to STATE_TURNING_ON, and some time later transition to either STATE_OFF or STATE_ON. If this call returns false then there was an immediate problem that will prevent the adapter from being turned on - such as Airplane mode, or the adapter is already turned on.
UPDATE:
Ok, so how to implement bluetooth listener?:
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
BluetoothAdapter.ERROR);
switch (state) {
case BluetoothAdapter.STATE_OFF:
// Bluetooth has been turned off;
break;
case BluetoothAdapter.STATE_TURNING_OFF:
// Bluetooth is turning off;
break;
case BluetoothAdapter.STATE_ON:
// Bluetooth is on
break;
case BluetoothAdapter.STATE_TURNING_ON:
// Bluetooth is turning on
break;
}
}
}
};
And how to register/unregister the receiver? (In your Activity class)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// ...
// Register for broadcasts on BluetoothAdapter state change
IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mReceiver, filter);
}
@Override
public void onStop() {
super.onStop();
// ...
// Unregister broadcast listeners
unregisterReceiver(mReceiver);
}
Updated for Android 12:
AndroidManifest.xml -
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>
You must perform the standard permission request for BLUETOOTH_CONNECT as you would when requesting permission for storage or other "prompted" items.
Usage (Kotlin) -
val bluetoothAdapter = (getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager).adapter
if (bluetoothAdapter.isEnabled)
bluetoothAdapter.disable()
For Android 12 and above, BLUETOOTH and BLUETOOTH_ADMIN permissions are not necessary to retrieve the current state or toggle it, unless targeting lower APIs.
I have made a class to handle almost all this in Kotlin using Coroutines
class ActivityResultHandler(
private val registry: ActivityResultRegistry
) {
private val handlers = mutableListOf<ActivityResultLauncher<*>>()
fun unregisterHandlers() {
handlers.forEach {
it.unregister()
}
}
suspend fun requestLocationPermission(): Boolean {
return suspendCoroutine<Boolean> { continuation ->
val launcher = registry.register(
LOCATION_PERMISSION_REQUEST,
// lifecycleOwner,
ActivityResultContracts.RequestPermission()
) {
continuation.resumeWith(Result.success(it))
}
handlers.add(launcher)
launcher.launch(Manifest.permission.ACCESS_FINE_LOCATION)
}
}
suspend fun requestBluetoothActivation(): Boolean {
return suspendCoroutine<Boolean> { continuation ->
val enableBtIntent = Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)
val launcher = registry.register(
BLUETOOTH_ON_REQUEST,
// lifecycleOwner,
ActivityResultContracts.StartActivityForResult()
) { result ->
continuation.resume(
result.resultCode == Activity.RESULT_OK
)
}
handlers.add(launcher)
launcher.launch(enableBtIntent)
}
}
fun checkLocationPermission(context: Context): Boolean {
return ContextCompat.checkSelfPermission(
context,
Manifest.permission.ACCESS_FINE_LOCATION
) == PackageManager.PERMISSION_GRANTED
}
private suspend fun requestLocationActivation(
intentSenderRequest: IntentSenderRequest,
): Boolean {
return suspendCoroutine { continuation ->
val launcher = registry.register(
LOCATION_ACTIVATION_REQUEST,
// lifecycleOwner,
ActivityResultContracts.StartIntentSenderForResult()
) {
continuation.resume(it.resultCode == Activity.RESULT_OK)
}
handlers.add(launcher)
launcher.launch(intentSenderRequest)
}
}
suspend fun enableLocation(context: Context): Boolean =
suspendCoroutine { continuation ->
val locationSettingsRequest = LocationSettingsRequest.Builder()
// .setNeedBle(true)
.addLocationRequest(
LocationRequest.create().apply {
priority = LocationRequest.PRIORITY_HIGH_ACCURACY
}
)
.build()
val client: SettingsClient = LocationServices.getSettingsClient(context)
val task: Task<LocationSettingsResponse> =
client.checkLocationSettings(locationSettingsRequest)
task.addOnSuccessListener {
continuation.resume(true)
}
task.addOnFailureListener { exception ->
if (exception is ResolvableApiException &&
exception.statusCode == LocationSettingsStatusCodes.RESOLUTION_REQUIRED
) {
val intentSenderRequest =
IntentSenderRequest.Builder(exception.resolution).build()
CoroutineScope(continuation.context).launch {
val result = requestLocationActivation(intentSenderRequest)
continuation.resume(result)
}
} else {
continuation.resume(false)
}
}
}
companion object {
private const val LOCATION_PERMISSION_REQUEST = "LOCATION_REQUEST"
private const val BLUETOOTH_ON_REQUEST = "LOCATION_REQUEST"
private const val LOCATION_ACTIVATION_REQUEST = "LOCATION_REQUEST"
}
}
Use it like this:
// make sure you extend AppCompatActivity
class MainActivity : AppCompatActivity() {
private val permissionRequests = ActivityResultHandler(activityResultRegistry)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// use viewmodels and fragments instead of GlobalScope
GlobalScope.launch {
// turn on bluetooth
permissionRequests.requestBluetoothActivation()
// to be able to scan for devices you also need location permission
// also show pop up to let users know why you need location
// https://support.google.com/googleplay/android-developer/answer/9799150?hl=en
permissionRequests.requestLocationPermission()
// also you need navigation to be enabled
permissionRequests.enableLocation(this@MainActivity)
}
}
override fun onDestroy() {
super.onDestroy()
permissionRequests.unregisterHandlers()
}
}
coroutines dependency in gradle
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.2'
also add this permissions to manifest
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission-sdk-23 android:name="android.permission.ACCESS_COARSE_LOCATION" />