c# Android - ISurfaceTextureListener 线程中断然后在 activity 关闭时恢复

Question

我有一个 activity（带有 ISurfaceTextureListener）和一个异步 OnSurfaceTextureUpdated 方法，我在其中调用异步 SendPixel 方法：

public async void OnSurfaceTextureUpdated(SurfaceTexture surface)
{
    bool sendPixel = false;

    [...]

    if (Settings.Pixel.period >= 0)
    {
        if (stopWatch.ElapsedMilliseconds >= Settings.Pixel.nextSending)
        {
            if (Settings.Pixel.period > 0)
                Settings.Pixel.nextSending += Settings.Pixel.period * ((int)((stopWatch.ElapsedMilliseconds - Settings.Pixel.nextSending) / Settings.Pixel.period) + 1);
            sendPixel = true;
        }
    }

    [...]

    if (sendPixel)
        await SendPixel();
}

这是异步 SendPixel 方法：

async Task SendPixel()
{
    try
    {
        if (Ev3Messaging.IsConnected())
        {
            Color color = new Color(bm.GetPixel(Settings.Camera.viewport.X_VpToCv(Settings.Pixel.x), Settings.Camera.viewport.X_VpToCv(Settings.Pixel.y)));
            Ev3Messaging.AddNumberMessage("MC_Hue", color.GetHue());
            Ev3Messaging.AddNumberMessage("MC_Brightness", color.GetBrightness());
            Console.WriteLine("SendPixel");
            await Ev3Messaging.SendMessages();
            Console.WriteLine("SendPixelEnd");
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine("Error SendPixel: " + ex.Message);
    }
}

ISurfaceTextureListener读取一个视频流，然后多次调用SendPixel方法。问题是控制台很好地显示 "SendPixel"，但不显示 "SendPixelEnd"，并且没有抛出任何错误。之后，当我关闭 activity 时，每个缺失的 "SendPixelEnd" 都会显示出来。

编辑：EV3Messaging.SendMessages 发送在前几行中添加的消息（通过蓝牙）：

static List<byte> btMessage = new List<byte>();
static public async Task SendMessages()
{
    if (_socket != null)
        await _socket.OutputStream.WriteAsync(btMessage.ToArray(), 0, btMessage.Count);
}

为什么会发生这种情况，我该如何解决？

提前致谢。

PS: 抱歉我的英语不好^^

Answer 1

已解决：我每次发送数据时都忘记清除 btMessage 列表，这导致了这种奇怪的行为。这个问题也可能是因为从蓝牙设备接收数据的方式不对。

然后 SendMessages 方法变为：

static public async Task SendMessages()
{
    if (_socket != null)
        await _socket.OutputStream.WriteAsync(btMessage.ToArray(), 0, btMessage.Count);
    btMessage.Clear();
}

因为我每次添加消息时，都会将新帧添加到 btMessage 列表的末尾。

此外，要获取传入消息，我使用此代码：

public static void InputMessagesManager(Action<BtMessage> incomingMessageEvent)
{
    _tokenSource = new CancellationTokenSource();
    Task t = Task.Factory.StartNew(async () =>
    {
        Stream inputStream = _socket.InputStream;

        while (!_tokenSource.IsCancellationRequested)
        {
            if (inputStream == null)
                inputStream = _socket.InputStream;
            if (inputStream != null && inputStream.CanRead)
            {
                await inputStream.ReadAsync(_sizeBuffer, 0, _sizeBuffer.Length);

                short size = (short)(_sizeBuffer[0] | _sizeBuffer[1] << 8);
                if (size != 0)
                {
                    byte[] frame = new byte[size];
                    await inputStream.ReadAsync(frame, 0, frame.Length);
                    BtMessage btMes = new BtMessage(frame);
                    incomingMessageEvent(btMes);
                    Console.WriteLine("Received: " + btMes.name + " -> " + btMes.getValueAsNumber());
                }
            }
        }
    }, _tokenSource2.Token, TaskCreationOptions.LongRunning, TaskScheduler.Current);
}

c# Android - ISurfaceTextureListener 线程中断然后在 activity 关闭时恢复

c# Android - ISurfaceTextureListener thread interrupted then resumed when activity closed

c#

multithreading

android

asynchronous

interruption