[英]Generate QR code with Xamarin.Forms and Zxing
I've seen alot about this online (old posts) but nothing seems to work for me. 我在网上看到了很多这样的帖子(旧帖子),但似乎没有什么对我有用。 I'm trying to generate a QR code out of a string and display it in the app. 我正在尝试从字符串中生成QR码并将其显示在应用程序中。
Here's what i had in the beginning 这就是我在开始时所拥有的
qrCode = new ZXingBarcodeImageView
{
BarcodeFormat = BarcodeFormat.QR_CODE,
BarcodeOptions = new QrCodeEncodingOptions
{
Height = 50,
Width = 50
},
BarcodeValue = codeValue,
VerticalOptions = LayoutOptions.CenterAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand
};
That works fine for Android but on IOS devices its not rendered at all. 这适用于Android,但在IOS设备上它根本没有渲染。 So after researching i tried to do it like this: 所以在研究之后我试着这样做:
Image qrCode;
if (Device.OS == TargetPlatform.iOS)
{
var writer = new BarcodeWriter
{
Format = BarcodeFormat.QR_CODE,
Options = new ZXing.Common.EncodingOptions
{
Width = 50,
Height = 50
}
};
var b = writer.Write(codeValue);
qrCode = new Image
{
Aspect = Aspect.AspectFill,
VerticalOptions = LayoutOptions.CenterAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand,
Source = ImageSource.FromStream(() =>
{
MemoryStream ms = new MemoryStream(b);
ms.Position = 0;
return ms;
})
};
}else{
qrCode = new ZXingBarcodeImageView
{
BarcodeFormat = BarcodeFormat.QR_CODE,
BarcodeOptions = new QrCodeEncodingOptions
{
Height = 50,
Width = 50
},
BarcodeValue = codeValue,
VerticalOptions = LayoutOptions.CenterAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand
};
}
Content = new StackLayout
{
Children = {
header, lblExplenationText, qrCode
},
BackgroundColor = Color.White
};
But there is still nothing rendered at all. 但是仍然没有任何渲染。
ZXing.Mobile.Forms NuGet Package Version: 2.1.47 (newest) ZXing.Mobile.Forms NuGet包版本:2.1.47(最新)
It seems to be a known issue . 这似乎是一个众所周知的问题 。
Luckily there is a workaround, to set a HeightRequest
& WidthRequest
, here is a working code example: 幸运的是,有一个解决方法,设置HeightRequest
和WidthRequest
,这是一个工作代码示例:
ZXingBarcodeImageView GenerateQR(string codeValue)
{
var qrCode = new ZXingBarcodeImageView
{
BarcodeFormat = BarcodeFormat.QR_CODE,
BarcodeOptions = new QrCodeEncodingOptions
{
Height = 350,
Width = 350
},
BarcodeValue = codeValue,
VerticalOptions = LayoutOptions.CenterAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand
};
// Workaround for iOS
qrCode.WidthRequest = 350;
qrCode.HeightRequest = 350;
return qrCode;
}
Add in the app delegate this line ZXing.Net.Mobile.Forms.iOS.Platform.Init(); 在app中添加委托此行ZXing.Net.Mobile.Forms.iOS.Platform.Init();
before LoadApplication(new App()); 在LoadApplication之前(new App());
and ready ... 准备好......
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