android - 如何监控蓝牙 HID 小工具的所有输入

Question

我正在尝试实现一个应用程序，该应用程序(错误)使用蓝牙相机快门释放小工具来实现完全不同的目的。这是有问题的小工具:

http://www.amazon.co.uk/iPazzPort-Bluetooth-Shutter-Android-Smartphones/dp/B00MRTFB4M

据我所知，它使用蓝牙 v3 并且是 HID 设备。它显然是通过模拟“音量增大”(或者可能是“音量减小”？)来触发相机应用程序快门。不管怎样，它似乎工作得很好，尽管有时你必须按两次按钮 - 我认为也许第一次按会重新建立蓝牙连接，第二次和随后的按然后就可以工作了。

我已经使用两台运行 Android 2.3 的不同设备对其进行了测试。我确实希望向后兼容该版本的 Android。

我想要做的是以某种方式监视来自该设备的所有输入，以便我的应用程序可以检测何时按下按钮，然后执行它想要使用该设备的操作。 (这是一种紧急警报系统，因此您可以按下按钮来表明您需要帮助。)

我不想尝试通过蓝牙与设备进行通信。 Android 已经这样做了，而且它正在发挥作用，而且我所读到的有关蓝牙和 HID 协议(protocol)的内容让我希望尽可能避免使用它。)

我尝试重写 onKeyDown() 、 onKeyUp() 和dispatchKeyEvent() 。有时他们会接到电话，有时则不会。当他们接到电话时，我看到了意想不到的键码，例如 66(Enter)和 8(“1”)。

我要问的是，是否有某种方法可以监控来自该蓝牙 HID 设备的所有输入，而无需参与蓝牙 HID 协议(protocol)支持？

Answer 1

我从来没有找到我的问题的真正答案，但幸运的是我找到了解决方法。

这个特殊的蓝牙小工具总是连接到配对的设备，发送一些文本，然后断开连接。所以我正在做的是创建一个 BroadcastReceiver 来获取蓝牙连接(和断开连接)事件，并使用它来激活警报。

   // Class used to receive Bluetooth connection and disconnect events. This checks the action is as
   // expected (probably unnecessary) and that a request type has been selected, and sends the
   // activation message to OutBack Server if so. (Monitoring the disconnect events is probably
   // unnecessary, but is done just in case that saves a situation where a connection has been
   // missed, or something.)
   public class BluetoothReceiver extends BroadcastReceiver {

      @Override
      public void onReceive(Context androidContext, Intent androidIntent) {

         String actionOrNull = androidIntent.getAction();
         if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(actionOrNull) ||
             BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(actionOrNull)) {
            Log.d(TAG, "BluetoothReceiver.onReceive() " + actionOrNull);
            if (_btnActivate.isEnabled()) {
               sendRequestActivationToServer();
            }
         }
      }
   }

...

   // Reference to the object used to monitor Bluetooth connections and disconnections
   private BluetoothReceiver _bluetoothReceiver = null;

...

   // Last lifecycle method called before fragment becomes active. This is apparently the
   // recommended place to register a receiver object, and is used to register a receiver object to
   // monitor Bluetooth connections and disconnections.
   @Override
   public void onResume() {
      super.onResume();

      _bluetoothReceiver = new BluetoothReceiver();

      IntentFilter intentFilter = new IntentFilter();
      intentFilter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
      intentFilter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);

      getActivity().registerReceiver(_bluetoothReceiver, intentFilter);
   }

...

   // First lifecycle method called when a fragment is on its way to being paused or destroyed. This
   // is apparently the recommended place to unregister a receiver object, and is used to unregister
   // the receiver object that monitors Bluetooth connections and disconnections.
   @Override
   public void onPause() {
      super.onPause();

      if (_bluetoothReceiver != null) {
         getActivity().unregisterReceiver(_bluetoothReceiver);
         _bluetoothReceiver = null;
      }
   }

这是受到这个问题和答案的启发:How to receive intents for Bluetooth devices working?