由于现有相机用户[XAMARIN.FORM]，无法使用相机“ 0”的割炬

如何解决由于现有相机用户[XAMARIN.FORM]，无法使用相机“ 0”的割炬

我遇到了无法解决的麻烦。 我正在做一个使用相机（如扫描仪）捕获QR码的Android Xamarin表单应用程序（为此，我使用Zxing NuGet软件包）。 当我尝试打开相机闪光灯时会发生问题（为此，我使用Xamarin.Exentials），但显然代码返回了异常（“ CAMERA_IN_USE（4）：setTorchMode：1732：相机“ 0”的割炬不是）由于现有的相机用户而可用”）。

注意：Flash Activator的按钮是工具栏->“ ToolbarItems”中的图标，而不是Zxing软件包中已集成的按钮。

我尝试了很多Web解决方案，但没有任何效果，我在下面发布了代码。谢谢！

protected override void OnAppearing()
    {
        base.OnAppearing();
        var zxing = new ZXingScannerView
        {
            HorizontalOptions = LayoutOptions.FillAndExpand,VerticalOptions = LayoutOptions.FillAndExpand,AutomationId = "zxingScannerView",IsTorchOn = false,IsScanning=true,IsAnalyzing=true,Options = new ZXing.Mobile.MobileBarcodeScanningOptions()
            {
                //IMPORTANT: this is used for stretch camera problem! //(interface: ZXingHelper.cs,file: ZxingHelper.cs)
                PossibleFormats = new List<ZXing.BarcodeFormat>() { ZXing.BarcodeFormat.QR_CODE },CameraResolutionSelector = DependencyService.Get<IZXingHelper>().SelectLowestResolutionMatchingDisplayAspectRatio
            }
        };

        zxing.OnScanResult += (result) =>
            Device.BeginInvokeOnMainThread(async () =>
            {

                // Stop analysis and scanning until we navigate away so we don't keep reading barcodes
                zxing.IsAnalyzing = false;
                zxing.IsScanning = false;

                // Show an alert
                await DisplayAlert("Scanned Barcode",result.Text,"OK");

                //Update QR saved List
                updateDataBase(result.Text);

                //Do Action After Update Scanner
                if (result.Text.StartsWith("http://") || result.Text.StartsWith("https://") || result.Text.StartsWith("www."))
                {
                    QRUrlModel qRUrlModel = new QRUrlModel();
                    qRUrlModel.url = result.Text;
                    await Xamarin.Essentials.Browser.OpenAsync(qRUrlModel.url,BrowserLaunchMode.SystemPreferred);
                }
                else
                {
                    //await Navigation.PushAsync(new BookmarkPage());
                }

            });

        var overlay = new ZXingDefaultOverlay
        {
            TopText = "Hold your phone up to the barcode",BottomText = "Scanning will happen automatically",//ShowFlashButton = true,AutomationId = "zxingDefaultOverlay",};

        overlay.FlashButtonClicked += (sender,e) =>
        {
            zxing.IsTorchOn = !zxing.IsTorchOn;
        };

        var Grid = new Grid
        {
            VerticalOptions = LayoutOptions.FillAndExpand,HorizontalOptions = LayoutOptions.FillAndExpand,};
        Grid.Children.Add(zxing);
        Grid.Children.Add(overlay);
        Content = Grid;
    }


private async void BtnFash_ToolbarItems(object sender,EventArgs e)
    {
       try
        {
            // Turn On Flashlight  
            await Flashlight.TurnOnAsync();
        }
        catch (FeatureNotSupportedException fnsEx)
        {
            await DisplayAlert("Attention",fnsEx.Message,"OK");
        }
        catch (PermissionException pEx)
        {
            await DisplayAlert("Attention",pEx.Message,"OK");
        }
        catch (Exception ex)
        {
            await DisplayAlert("Attention",ex.Message,"OK");
        }

}