android - 仅等待输入 X 时间

Question

我正在尝试从输入流中读取数据，但如果程序在 X 时间内没有接收到数据，我想终止尝试并返回 -1。我之前使用的是 Thread.sleep( X ) 但后来意识到这是一种完全不正确的方法。如果有人有任何想法，请告诉我。这是我从输入流中读取的代码...

            try {
                // Read from the InputStream
                bytes = mmInStream.read(buffer, 0, length);

                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(MainMenu.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                // Start the service over to restart listening mode
                BluetoothService.this.start();
                //break;
            }

Answer 1

您可以使用 Future做这个。

首先，您需要一个将作为“ future ”值返回的类:

public class ReadResult {
    public final int size;
    public final byte[] buffer;

    public ReadResult(int size, byte[] buffer) {
         this.size = size;
         this.buffer = buffer;
    }
}

然后需要使用executor服务，使用get(long timeout, TimeUnit unit)像这样:

        ExecutorService service = Executors.newSingleThreadExecutor();
        Future<ReadResult> future = service.submit(new Callable<ReadResult>() {

            @Override
            public ReadResult call() throws Exception {
                bytes = mInStream.read(buffer, 0, length);
                return new ReadResult(bytes, buffer);
            }
        });

        ReadResult result = null;
        try {
            result = future.get(10, TimeUnit.SECONDS);
        } catch (InterruptedException e1) {
            // Thread was interrupted
            e1.printStackTrace();
        } catch (ExecutionException e1) {
            // Something bad happened during reading
            e1.printStackTrace();
        } catch (TimeoutException e1) {
            // read timeout
            e1.printStackTrace();
        }

        if (result != null) {
            // here you can use it
        }

这样你就可以实现你的目标。请注意，最好将 Callable 类子类化，该类将接受输入流作为构造函数参数，然后使用类变量。