[英]cannot convert from UIKit.UIImage to ZXing.LuminanceSource - Xamarin iOS in Visual Studios 2017
我看到的所有示例都是針對Xamarin Forms的,而不是針對Xamarin for Visual Studios的。 我有一個正在使用Xamarin for Visual Studio開發的iOS應用程序,需要讀取條形碼。 我從NuGet將ZBar下載到Visual Studio 2017中並安裝了它,在那里沒有問題。 我可以訪問相機並捕獲圖像(條形碼),沒問題。 但是,似乎無法將從相機捕獲的UIKit.UIIMage轉換為“ ZXing.LuminanceSource”,以便可以對其進行解碼。 如果有人可以幫助我指出正確的方向,我將不勝感激。 我的代碼相當簡單,可從下載隨附的ZBar示例中獲取:
IBarcodeReader scanPage = new BarcodeReader();
var result = scanPage.Decode(theImage); // the image is public and is set to the image returned by the camera. It's here I get the error in intellisense "cannot convert from UIKit.UIImage to ZXing.LuminanceSource"
相機圖像返回碼:
[Foundation.Export("imagePickerController:didFinishPickingImage:editingInfo:")]
public void FinishedPickingImage(UIKit.UIImagePickerController picker, UIKit.UIImage image, Foundation.NSDictionary editingInfo)
{
theImage = MaxResizeImage(image, 540f, 960f);
picker.DismissModalViewController(false);
}
[Foundation.Export("imagePickerControllerDidCancel:")]
public void Canceled(UIKit.UIImagePickerController picker)
{
DismissViewController(true, null);
}
public static UIImage MaxResizeImage(UIImage sourceImage, float maxWidth, float maxHeight)
{
var sourceSize = sourceImage.Size;
var maxResizeFactor = Math.Min(maxWidth / sourceSize.Width, maxHeight / sourceSize.Height);
if (maxResizeFactor > 1) return sourceImage;
var width = maxResizeFactor * sourceSize.Width;
var height = maxResizeFactor * sourceSize.Height;
UIGraphics.BeginImageContext(new CGSize((nfloat)width, (nfloat)height));
sourceImage.Draw(new CGRect(0, 0, (nfloat)width, (nfloat)height));
var resultImage = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return resultImage;
}
}
在@Jason的一些幫助下,我設法解決了該問題,謝謝Jason。 我從NuGet下載並安裝了ZXing.Net.Mobile和ZXing.Net.Mobile.Forms。 Xamarin-Visual Studios都需要。 刪除了所有攝像機代碼,並替換為3行代碼,此外,我還需要在button_TouchUpInside調用中添加async
代碼。
在AppDelegate FinishedLaunching中:
public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
{
// Override point for customization after application launch.
// If not required for your application you can safely delete this method
// Add this line to initialize ZXing
ZXing.Net.Mobile.Forms.iOS.Platform.Init();
return true;
}
將按鈕代碼更改為此,使按鈕async
await
掃描結果:
async partial void ScanBarCode_TouchUpInside(UIButton sender)
{
// Create scanner
var scanner = new ZXing.Mobile.MobileBarcodeScanner();
// Store result of scan in var result, need to await scan
var result = await scanner.Scan();
// display bar code number in text field
Textbox_BarCode.Text = result.Text;
}
每次都工作(因此很遠)。
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