Android 扫描附近的蓝牙设备并连接蓝牙音响的示例

public class ScanDeviceActivity extends AppCompatActivity { private LoadingDialog loadingDialog; private DeviceAdapter deviceAdapter; private BluetoothAdapter bluetoothAdapter; private Handler handler = new Handler(); private BroadcastReceiver discoveryReceiver = new BroadcastReceiver() {  @Override  public void onReceive(Context context, Intent intent) {   switch (intent.getAction()) {    case BluetoothAdapter.ACTION_DISCOVERY_STARTED:     showLoadingDialog("正在搜索附近的蓝牙设备");     break;    case BluetoothAdapter.ACTION_DISCOVERY_FINISHED:     Toast.makeText(ScanDeviceActivity.this, "搜索结束", Toast.LENGTH_SHORT).show();     hideLoadingDialog();     break;    case BluetoothDevice.ACTION_FOUND:     BluetoothDevice bluetoothDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);     deviceAdapter.addDevice(bluetoothDevice);     deviceAdapter.notifyDataSetChanged();     break;   }  } }; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_scan_device);  BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);  bluetoothAdapter = bluetoothManager.getAdapter();  if (bluetoothAdapter == null) {   Toast.makeText(this, "当前设备不支持蓝牙", Toast.LENGTH_SHORT).show();   finish();  }  initView();  registerDiscoveryReceiver();  startScan(); } @Override protected void onDestroy() {  super.onDestroy();  handler.removeCallbacksAndMessages(null);  unregisterReceiver(discoveryReceiver);  if (bluetoothAdapter.isDiscovering()) {   bluetoothAdapter.cancelDiscovery();  } } private void initView() {  ListView lv_deviceList = (ListView) findViewById(R.id.lv_deviceList);  deviceAdapter = new DeviceAdapter(this);  lv_deviceList.setAdapter(deviceAdapter); } private void registerDiscoveryReceiver() {  IntentFilter intentFilter = new IntentFilter();  intentFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);  intentFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);  intentFilter.addAction(BluetoothDevice.ACTION_FOUND);  intentFilter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);  registerReceiver(discoveryReceiver, intentFilter); } private void startScan() {  if (!bluetoothAdapter.isEnabled()) {   if (bluetoothAdapter.enable()) {    handler.postDelayed(new Runnable() {     @Override     public void run() {      scanDevice();     }    }, 1500);   } else {    Toast.makeText(this, "请求蓝牙权限被拒绝，请授权", Toast.LENGTH_SHORT).show();   }  } else {   scanDevice();  } } private void scanDevice() {  if (bluetoothAdapter.isDiscovering()) {   bluetoothAdapter.cancelDiscovery();  }  bluetoothAdapter.startDiscovery(); } private void showLoadingDialog(String message) {  if (loadingDialog == null) {   loadingDialog = new LoadingDialog(this);  }  loadingDialog.show(message, true, false); } private void hideLoadingDialog() {  if (loadingDialog != null) {   loadingDialog.dismiss();  } }}