Question

我找到所有可用的蓝牙设备，然后当用户点击列表中的元素时，我想将我的设备与所选地址配对，并取消发现。但是，我对蓝牙适配器的cancelDiscovery（）调用始终返回false。在android文档中，它说适配器必须在STATE_ON中，cancelDiscovery（）才能返回true。但是，当我调用btAdapter.getState（）时，它返回值12，即STATE_ON。我的代码如下，有谁知道还有什么可能是错的？

当当前状态为STATE_ON时，我不明白cancelDiscovery（）返回false的方式。文档说如果状态是STATE_ON则返回true，所有其他值则返回false。

    private static final UUID MY_UUID = UUID.randomUUID();

private static final int REQUEST_ENABLE_BT = 1;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    btnScanDevice = (Button) findViewById( R.id.scandevice );

    stateBluetooth = (TextView) findViewById( R.id.bluetoothstate );
    startBluetooth();

    listDevicesFound = (ListView) findViewById( R.id.devicesfound );
    btArrayAdapter = new ArrayAdapter<String>( AndroidBluetooth.this,
            android.R.layout.simple_list_item_1 );
    listDevicesFound.setAdapter( btArrayAdapter );

    CheckBlueToothState();

    btnScanDevice.setOnClickListener( btnScanDeviceOnClickListener );

    registerReceiver( ActionFoundReceiver, new IntentFilter( BluetoothDevice.ACTION_FOUND ) );

    listDevicesFound.setOnItemClickListener( new OnItemClickListener()
    {
      public void onItemClick(AdapterView<?> arg0, View arg1,int arg2, long arg3) 
      {
          Log.i("Discovery: ", Integer.toString( myBtAdapter.getState() ) );
          boolean success = myBtAdapter.cancelDiscovery();
          myBtDevice = btDevicesFound.get( arg2 );
          try {
              btSocket = myBtDevice.createRfcommSocketToServiceRecord( MY_UUID );
              iStream = btSocket.getInputStream();
              oStream = btSocket.getOutputStream();
          } catch ( IOException e ) {
              Log.e( "Bluetooth Socket", "Bluetooth not available, or insufficient permissions" );
          } catch ( NullPointerException e ) {
              Log.e( "Bluetooth Socket", "Null Pointer One" );
          }
          CheckBlueToothState();
          try {
              btSocket.connect();
          } catch ( IOException e ) {
              Log.e( "Bluetooth Socket", "Problems arose while attempting to connect." );
          } catch ( NullPointerException e ) {
              Log.e( "Bluetooth Socket", "Null Pointer Two" );
          }
      }

  });
}

private void CheckBlueToothState() {
    if( myBtAdapter == null ) {
        stateBluetooth.setText("Bluetooth NOT supported" );
    } else {
        if( myBtAdapter.isEnabled() ) {
            if( myBtAdapter.isDiscovering() ) {
                stateBluetooth.setText( "Bluetooth is currently " +
                        "in device discovery process." );
            } else {
                stateBluetooth.setText( "Bluetooth is Enabled." );
                btnScanDevice.setEnabled( true );
            }
        } else {
            stateBluetooth.setText( "Bluetooth is NOT enabled" );
            Intent enableBtIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE );
            startActivityForResult( enableBtIntent, REQUEST_ENABLE_BT );
        }
    }
}

private Button.OnClickListener btnScanDeviceOnClickListener = new Button.OnClickListener() {
    public void onClick( View arg0 ) {
        btArrayAdapter.clear();
        myBtAdapter.startDiscovery();
    }
};


@Override
protected void onActivityResult( int requestCode, int resultCode, Intent data ) {
    if( requestCode == REQUEST_ENABLE_BT ) {
        CheckBlueToothState();
    }
}

private final BroadcastReceiver ActionFoundReceiver = new BroadcastReceiver() {
    public void onReceive( Context context, Intent intent ) {
        String action = intent.getAction();
        if( BluetoothDevice.ACTION_FOUND.equals( action ) ) {
            BluetoothDevice btDevice = intent.getParcelableExtra( BluetoothDevice.EXTRA_DEVICE );
            btDevicesFound.add( btDevice );
            btArrayAdapter.add( btDevice.getName() + "\n" + btDevice.getAddress() );
            btArrayAdapter.notifyDataSetChanged();
        }           
    }
};
public static void startBluetooth(){
    try {
        myBtAdapter = BluetoothAdapter.getDefaultAdapter();
        myBtAdapter.enable();
    } catch ( NullPointerException ex ) {
        Log.e( "Bluetooth", "Device not available" );
    }
}

public static void stopBluetooth() {
    myBtAdapter.disable();
}
}

Answer 1

我清理了我的项目，对于任何看这个帖子的人来说，它都能正常工作。

cancelDiscovery一直返回false

1 个答案: