java - 使输入流继续读取直到程序关闭的正确方法？

Question

我正在使用带有键盘的设备，并且我想无限期地监听按键操作。我在 while(true) 循环中有一个 inputStream.read() ，它可以工作......直到我希望停止读取输入。那时，我将停留在 inputStream.read() 上，直到输入其他内容。

try {

    // Call api and get input stream
    Call<ResponseBody> call = clockUserAPI.getKeyboardStream();
    Response<ResponseBody> response = call.execute();
    inputStream = response.body().byteStream();

    // Continuously run <<<<<<<<<<<<<<<<<
    while (keepReading) {

        // Read from input stream
        Log.w(TAG, "Reading from input stream");
        final byte[] buffer = new byte[256];
        int bytesRead = bytesRead = inputStream.read(buffer, 0, buffer.length);

        // Process response
        Log.v(TAG, bytesRead + " bytes read. Now precessing");
        String fullResponse = new String(buffer, 0, bytesRead, StandardCharsets.UTF_8);         
        processResponse(fullResponse);

        try { Thread.sleep(100); } catch (InterruptedException e1) { e1.printStackTrace(); }       

    } catch (Exception e) {
        e.printStackTrace();

        // Sleep for a sec
        Log.d(TAG, "Keyboard thread interrupted");
        try { Thread.sleep(1000); } catch (InterruptedException e1) { e1.printStackTrace(); }

        // Something happened. Close the input stream
        if (inputStream != null) {
            try {
                Log.v(TAG, "Closing input stream");
                inputStream.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                Thread.sleep(500);
            } catch (InterruptedException e1) {
                e1.printStackTrace();
            }
            inputStream = null;
        }
    }
}

有关输入流和连续输入的最佳实践是什么？

Answer 1

如果我理解正确，您的问题是停止从 InputStream 读取。您可以使用 volatile boolean 变量来停止读取:

class PollingRunnable implements Runnable{

    private static final String TAG = PollingRunnable.class.getSimpleName();

    private InputStream inputStream;
    private volatile boolean shouldKeepPolling = true;

    public PollingRunnable(InputStream inputStream) {
        this.inputStream = inputStream;
    }


    public void stopPolling() {
        shouldKeepPolling = false;
    }

    @Override
    public void run() {
        while (shouldKeepPolling) {
            final byte[] buffer = new byte[256];
            int bytesRead = 0;
            try {
                bytesRead = inputStream.read(buffer, 0, buffer.length);
                String fullResponse = new String(buffer, 0, bytesRead, StandardCharsets.UTF_8);
                //Process response
            } catch (IOException e) {
                Log.e(TAG, "Exception while polling input stream! ", e);
            } finally {
                if(inputStream != null) {
                    try {
                        inputStream.close();
                    } catch (IOException e1) {
                        Log.e(TAG, "Exception while closing input stream! ", e1);
                    }
                }
            }
        }
    }
}

要停止轮询，只需使用:

// Supply you input stream here
PollingRunnable pollingRunnable = new PollingRunnable(inputStream);
new Thread(pollingRunnable).start();

//To stop polling 
pollingRunnable.stopPolling();