问题一:在Android蓝牙编程中,有时可以连接,有时不可以连接。不可以连接的原因是:在执行socket.connect()时,总抛出IOException:Unable to start service discovery.
刚开始我就直接百度找解决方案,可是都没有相关的解决方案,原以为是不稳定,并不是自己程序有问题。最后,还是看了看Android SDK API,才发现问题在哪,在BluetoothSocket的对象执行connect()之前,必须保证结束发现设备,即保证BluetoothAdapter的对象已经执行cancelDiscovery()
问题二:可是在执行下面代码BluetoothRev类时,怎样才能执行到符合条件BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)的代码
因为刚开始接触到蓝牙,所以直接从网上找的代码。代码中只有
bluetoothDevices.removeAll(bluetoothDevices); bluetoothRev=new BluetoothRev(); IntentFilter discoveryFilter=new IntentFilter(BluetoothDevice.ACTION_FOUND); registerReceiver(bluetoothRev, discoveryFilter);
对于该问题我纠结了老半天,从网上也没找到答案,最后发现还得加上
IntentFilter discoveryFilter=new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); registerReceiver(bluetoothRev, discoveryFilter);
才能执行到符合条件BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)的代码
private class BluetoothRev extends BroadcastReceiver{
@Override public void onReceive(Context context, Intent intent) { // TODO Auto-generated method stub String action=intent .getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent device=intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); isfound=true; bluetoothDevices.add(device); Toast.makeText(MainActivity.this , device.getName(), 50).show(); Toast.makeText(MainActivity.this , "已获取设备,可连接", 50).show(); client.setText("停止"); } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { if (isfound==false) { msg.setText("未发现设备,重新搜索"); } else { msg.setText("发现设备"); } adapter.cancelDiscovery(); MainActivity.this.unregisterReceiver(this ); } } }