ZXing.Mobile - 如何更改相机扫描仪的尺寸？

Question

UPDATE：

我试过在一个名为OpenCameraScanner的App.cs方法实现这一点（你会调用这个从要扫描的页面上点击按钮）：

App.cs 
------------------------------------------------ 
public static ZXingScannerPage ScanPage; 
public static ZXing.Result ScanResult; 

public static async void OpenCameraScanner() 
{ 
    ScanPage = new ZXingScannerPage(customOverlay: customOverlay); 
    ScanPage.OnScanResult += (result) => 
    { 
     ScanPage.IsScanning = false; 
     ScanResult = result; 

     Device.BeginInvokeOnMainThread(() => 
     { 
      App.CurrentApp.CurrentPage.Navigation.PopModalAsync(); 
      App.CurrentApp.CurrentPage.DisplayAlert("Scanned Barcode", result.Text, "OK"); 
     }); 
    }; 
    var scanPage = new NavigationPage(ScanPage); 
    await App.CurrentApp.CurrentPage.Navigation.PushModalAsync(ScanPage); 
} 

但是，当调用此方法时，打开的屏幕为空白，并且无法看到它后面的相机视图。不知道为什么？

---

我在一家Xamarin.Forms项目中使用ZXing.Mobile（iOS设备现在）用于iPad上的相机扫描功能。

目前，我把它用下面的2行工作的伟大：

var scanner = new ZXing.Mobile.MobileBarcodeScanner(); 
var result = await scanner.Scan(); 

然而，当摄像头打开时进行扫描，它占用了整个iPad的屏幕，这是非常大的。

问题：有没有办法调整摄像头覆盖的大小？ （所以它不是全屏幕）

我看到scanner.Scan()方法采用ZXing.Mobile.MobileBarcodeScanningOptions类型的可选参数选项 - 我试着用，玩左右，但唯一可能的相关选项有一个CameraResolutionSelector - 但我有很难找到任何相关的文档。

Answer 1

有一个斑马线示例应用程序，演示如何嵌入ZXingScannerView和ZXingDefaultOverlay成Xamarin.Form的Grid：

https://github.com/Redth/ZXing.Net.Mobile/blob/master/Samples/Forms/Core/CustomScanPage.cs

public CustomScanPage() : base() 
{ 
    zxing = new ZXingScannerView 
    { 
     HorizontalOptions = LayoutOptions.FillAndExpand, 
     VerticalOptions = LayoutOptions.FillAndExpand, 
     AutomationId = "zxingScannerView", 
    }; 
    zxing.OnScanResult += (result) => 
     Device.BeginInvokeOnMainThread (async() => { 

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

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

      // Navigate away 
      await Navigation.PopAsync(); 
     }); 

    overlay = new ZXingDefaultOverlay 
    { 
     TopText = "Hold your phone up to the barcode", 
     BottomText = "Scanning will happen automatically", 
     ShowFlashButton = zxing.HasTorch, 
     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); 

    // The root page of your application 
    Content = grid; 
}