Android藍牙發現找不到設備

Question

我有一個非常簡單的活動，可通過藍牙發現其他android設備：

public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);

     // Get the local Bluetooth adapter
    FrameLayout f = new FrameLayout(this);
    setContentView(f);
    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);

    this.registerReceiver(mReceiver, filter);
     // Register for broadcasts when discovery has finished
    filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    this.registerReceiver(mReceiver, filter);

    mBtAdapter = BluetoothAdapter.getDefaultAdapter();

    // Get a set of currently paired devices
    Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();


    // Request discover from BluetoothAdapter
    Log.i("bluetooth", "about to start device discovery");
    mBtAdapter.startDiscovery();

    //start receiving stuff
    mReceiver = new BluetoothReceiver();

}

問題是，在活動的onCreate（）結束時調用的BluetoothRecieiver類似乎找不到設備，盡管在調試時我在附近打開了一個藍牙設備：

 public class BluetoothReceiver extends BroadcastReceiver {
public ArrayAdapter<String> mNewDevicesArrayAdapter;
 @Override
 public void onReceive(Context context, Intent intent) {
     String action = intent.getAction();

     // 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.getBondState() != BluetoothDevice.BOND_BONDED) {
            Log.i("face", device.getName() + "\n" + device.getAddress());
             mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
         }
     // When discovery is finished, change the Activity title
     } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {

         if (mNewDevicesArrayAdapter.getCount() == 0) {
                Log.i("face", "found NOTHING!");
             mNewDevicesArrayAdapter.add("no devices found");
         }
      }
   }
}

我在這里想念什么嗎？

Answer 1

我認為這是因為當您調用registerReceiver() mReceiver為null時，請移動mReceiver = new BluetoothReceiver(); 在第一個this.registerReceiver(mReceiver, filter); ，你也可以做類似的事情

filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);

然后調用this.registerReceiver(mReceiver, filter); 只有一次