java - 等待接收数据而不阻塞ui线程蓝牙android

Question

我是 Android 编程新手，正在编写一个使用蓝牙的回合制游戏的简单应用程序。我的应用程序由 Main Activity 和 SecondActivity 组成，Main Activity 负责启动蓝牙连接并交换一些配置消息，而 SecondActivity 则通过游戏 map 实现自定义 View 。即使在自定义 View 中，我也可以正确配对设备并在两者之间交换信息，问题是在自定义 View 中我会等待接收信息而不阻塞 ui 线程，目前我正在以这种方式等待接收数据

自定义 View

state = bluetoothService.getState();
while(state != NOT_EMPTY){
    try {
        Thread.sleep(500);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    state = bluetoothService.getState();
}
info = bluetoothService.getMessage();

这显然会导致黑屏和无响应，是否有其他方法等待接收数据？

连接是通过 BluetoothService 类通过线程进行管理的，负责读取数据的线程负责执行此操作

private class ConnectedThread extends Thread {
        private final BluetoothSocket mSocket;
        private final InputStream mInStream;
        private final OutputStream mOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            mSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            try {
                tmpIn = mSocket.getInputStream();
                tmpOut = mSocket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }

            mInStream = tmpIn;
            mOutStream = tmpOut;
        }

        public void run(){
            byte[] buffer = new byte[1024]; 

            int bytes; // bytes returned from read()

            // Keep listening to the InputStream until an exception occurs
            while (true) {
                // Read from the InputStream
                try {
                    bytes = mInStream.read(buffer);
                    if(bytes != 0) {
                        String incomingMessage = new String(buffer, 0, bytes);
                        message = incomingMessage;
                        mState = NOT_EMPTY;
                    }
                } catch (IOException e) {
                    break;
                }
            }
        }
}

//getMessage method just returns message if not null

Answer 1

主要思想不是从 Activity 中拉取，而是从后台线程调用 Activity 的方法。

因此，在构造读取器线程时，传递对 Activity 的引用并创建一个处理程序:

    private SecondActivity mActivity;
    private Handler mActivityHandler;

    public ConnectedThread(BluetoothSocket socket, SecondActivity activity) {
        mActivity = activity;
        mActivityHandler = new Handler(activity.getMainLooper());

        ...
    }

收到消息后，调用 Activity 的方法。该调用必须在主线程上完成，因此使用处理程序:

final String message = incomingMessage;
Runnable runnable = new Runnable() {
    @Override 
    public void run() {
        mActivity.onMessageReceived(message);
    } 
};
mActivityHandler.post(myRunnable);

在 Activity 中，对消息执行一些操作:

public void onMessageReceived(String message) {
    // handle the message...
}