Android 蓝牙 send/receive 哈希图

Question

我正在尝试通过蓝牙将哈希图从一台设备发送到另一台设备。我正在这样创建哈希图，然后调用连接线程 writeObject 方法：

Map<String,String> subInfo = new HashMap<>();
subInfo.put("type", "subInfo");
subInfo.put("num", "1");
BTService.connectedThread.writeObject(subInfo);

我的蓝牙服务有以下 class 用于在后台线程中处理设备之间的数据传输：

public static class ConnectedThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;
        private final ObjectInputStream mmObjInStream;
        private final ObjectOutputStream mmObjOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            mmSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;
            ObjectInputStream tmpObjIn = null;
            ObjectOutputStream tmpObjOut = null;

            // Get the input and output streams, using temp objects because
            // member streams are final
            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
                tmpObjIn = new ObjectInputStream(socket.getInputStream());
                tmpObjOut = new ObjectOutputStream(socket.getOutputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;
            mmObjInStream = tmpObjIn;
            mmObjOutStream = tmpObjOut;
        }

        public void run() {
            byte[] buffer = new byte[1024];  // buffer store for the stream
            int bytes; // bytes returned from read()

            // Keep listening to the InputStream until an exception occurs
            while (!this.isInterrupted()) {
                try {
                    // Read from the InputStream
                    bytes = mmInStream.read(buffer);
                    // Send the obtained bytes to the UI activity
                    mHandler.obtainMessage(Constants.MESSAGE_READ, bytes, -1, buffer)
                            .sendToTarget();
                } catch (IOException e) {
                    e.printStackTrace();
                    break;
                }

                try {
                    //Read objects from ObjectInputStream
                    Object object = mmObjInStream.readObject();
                    // Send the obtained object to the UI activity
                    mHandler.obtainMessage(Constants.MESSAGE_READ_OBJECT, -1, 0, object)
                            .sendToTarget();
                } catch (ClassNotFoundException | IOException e) {
                    e.printStackTrace();
                }
            }
        }

        /* Call this from the main activity to send data to the remote device */
        public void write(byte[] bytes) {
            try {
                mmOutStream.write(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        public void writeObject(Object object) {
            try {
                mmObjOutStream.writeObject(object);
            }catch(Exception e){
                Log.e(TAG, "Error ObjectOutputStream: " + e.getLocalizedMessage());
            }
        }

        /* Call this from the main activity to shutdown the connection */
        public void cancel() {
            try {
                mmSocket.close();
                this.interrupt();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

所以当我调用 writeObject 方法时，它应该将对象发送到上面线程的对象输出流中。

在其他设备上，代码类似。它只是在对象输入流上侦听对象，一旦找到它，它就会向主 activity:

中的消息处理程序发送一条 MESSAGE_READ_OBJECT 消息

static class MessageHandler extends Handler {
        private final WeakReference<MainActivity> mActivity;

        MessageHandler(MainActivity activity) {
            mActivity = new WeakReference<>(activity);
        }
        @Override
        public void handleMessage(Message msg)
        {
            final MainActivity mainActivity = mActivity.get();
            if (mainActivity == null) {
                return;
            }
            switch(msg.what){

                case Constants.MESSAGE_READ_OBJECT:
                    Object receivedObject = msg.obj;

                    //How should I pull out the hashmap here?

                    switch(type){
                        case "subInfo":
                            //do some things
                            break;
                    }
                    break;
            }
        }
    }

在我的消息处理程序中重新组合散列图的正确方法是什么？我需要检查地图的 "type" 键并根据它进行切换，但截至目前我不确定如何取回地图对象。我的消息处理程序中的 receivedObject 对象的行为似乎不像哈希图，并且没有用于提取键和值的典型方法

此外，与其通过蓝牙发送通用的 Object，不如直接发送 Map 类型的对象更有意义？

Answer 1

直接转换即可

HashMap mHashmap = (HashMap) obj;

这就是我所做的， https://github.com/zhenbeiju/AndroidCommonUtil/blob/master/app/src/main/java/commanutil/utl/file/ObjUtil.java

用法：https://coding.net/u/zhenbeiju/p/javanlp_/git/blob/master/src/com/voice/common/util/nlp/Main.java

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