Windows Phone 8.1 MediaCapture会冻结手机

Question

我想制作一个简单的应用程序,这将允许我检查每个预览框架的几个参数,但我遇到了运行和停止预览.

    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        MediaCapture _MediaCapture;
        bool _recording;
        public MainPage()
        {
            this.InitializeComponent();

            this.NavigationCacheMode = NavigationCacheMode.Required;
        }

        /// <summary>
        /// Invoked when this page is about to be displayed in a Frame.
        /// </summary>
        /// <param name="e">Event data that describes how this page was reached.
        /// This parameter is typically used to configure the page.</param>
        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            var devices = await Windows.Devices.Enumeration.DeviceInformation.FindAllAsync(DeviceClass.VideoCapture);


            var rearCamera = devices[0];
            if (devices.Count > 0)
            {

                rearCamera = devices.Single(currDev =>
                  currDev.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Back
                );
            }

            _MediaCapture = new MediaCapture();
            await _MediaCapture.InitializeAsync(new MediaCaptureInitializationSettings() { VideoDeviceId = rearCamera.Id });

// this is CaptureElement
            xCapture.Source = _MediaCapture;

            _recording = false;
        }

        protected override async void OnNavigatedFrom(NavigationEventArgs e)
        {
            if(_MediaCapture != null)
            {
                await _MediaCapture.StopPreviewAsync();
                await _MediaCapture.StopRecordAsync();

                _MediaCapture.Dispose();
                _MediaCapture = null;

                xCapture.Source = null;
            }


            base.OnNavigatedFrom(e);


        }

// button click handler
        private async void StartMeasure(object sender, RoutedEventArgs e)
        {
            if (_recording)
            {
                //await _MediaCapture.StopPreviewAsync();
                _MediaCapture.VideoDeviceController.TorchControl.Enabled = false;
                _recording = false;
            }
            else
            {
                //await _MediaCapture.StartPreviewAsync();
                _MediaCapture.VideoDeviceController.TorchControl.Enabled = true;
                _recording = true;
            }
        }
    }

在这种形式下,它完美地运作.

如果我取消注释那些预览行,它只能运行一次.

如果我按下按钮三次:打开,关闭和再次打开我在启用TorchControl时会出现异常.

System.Exception:来自HRESULT的异常:位于Pulsometr3.MainPage.d__d.MoveNext()的Windows.Media.Devices.TorchControl.put_Enabled(布尔值)的0xE801000D

HRESULT各不相同.

更奇怪的是,它有时会冻结手机(比如3次中的2次),我需要按住Power + Volume Down.

我尝试使用[STAThread]装饰所有方法,但它没有帮助(http://technet.microsoft.com/en-ca/br226599).

更有趣的是,当我通过debbuger使用F10执行操作来跨越线路时,我可以根据需要多次切换预览.这很糟糕,因为调试器拥有所有线程,对吗？所以理论上没有区别？

此外,手机有时会冻结部署...而这只是令人讨厌.

有任何想法吗？

Answer 1

我对此很感兴趣……出于某种原因，微软不太关心它的 WP8 后继操作系统，这让我真的很难过。但这也是半年前的夏天，我尝试过这个，也许你可以尝试谷歌搜索应用程序同意，并仔细检查你的应用程序清单，如果你勾选了前置/后置摄像头和网络摄像头:)此外如果它不起作用，那么运气不好，你应该坚持使用 wp 8.0 版本，它在 wp 8.1 上的工作原理完全相同，所以不用担心:)其他库，如 facebook stuff 或 parse.com 也将无法工作在 wp 8.1 C# 上:)