ZXing QR Code Generation in Xamarin Forms PCL - xamarin

Question

I'm trying to generate and display QR code using ZXing package, I tried in following code I was not able to show QR code. It's showing blank image (transparent).
private void OnGenerateQRCodeButton_Clicked(object sender, EventArgs e)
{
var writer = new BarcodeWriter
{
Format = BarcodeFormat.QR_CODE,
Options = new EncodingOptions
{
Height = (int)imageCompanyLogo.Height,
Width = (int) imageCompanyLogo.Width,
Margin = 0,
PureBarcode = true
}
};
var bitmap = writer.Write("www.helloworld.com");
imageQRCode.Source = ImageSource.FromStream(() => new MemoryStream(bitmap));
}
Please suggest any way to do it. Thanks.

Answer 1

Create interface in PCL(Xamarin) project for Dependency Service.
Create a class in Native(Xamarin.Droid) and Inherit from PCL Interface.
Implement the method as shown below.
public Stream ConvertImageStream(string text, int width = 300, int height = 300)
{
var barcodeWriter = new ZXing.Mobile.BarcodeWriter
{
Format = ZXing.BarcodeFormat.QR_CODE,
Options = new ZXing.Common.EncodingOptions
{
Width = width,
Height = height,
Margin = 10
}
};
barcodeWriter.Renderer = new ZXing.Mobile.BitmapRenderer();
var bitmap = barcodeWriter.Write(text);
var stream = new MemoryStream();
bitmap.Compress(Bitmap.CompressFormat.Png, 100, stream); // this is the diff between iOS and Android
stream.Position = 0;
return stream;
}
call the method from PCL(Xamarin) project using Dependency Service.
In xaml.cs
private void OnGenerateQRCodeButton_Clicked(object sender, EventArgs e)
{
string barcodeText = "www.helloworld.com";
var stream = DependencyService.Get<IBarCodeServices>().ConvertImageStream(barcodeText, (int)imageCompanyLogo.Width,(int) imageCompanyLogo.Height);
barcodeImage.Source = ImageSource.FromStream(() => stream);
}

Answer 2

Debug and see if stream in empty or not.
var stream = (Stream)null;
private void OnGenerateQRCodeButton_Clicked(object sender, EventArgs e)
{
var writer = new BarcodeWriter
{
Format = BarcodeFormat.QR_CODE,
Options = new EncodingOptions
{
Height = (int)imageCompanyLogo.Height,
Width = (int) imageCompanyLogo.Width,
Margin = 0,
PureBarcode = true
}
};
using(var bitmap = barcodeWriter.Write("www.helloworld.com"))
{
stream = new MemoryStream();
bitmap.Save(stream, ImageFormat.Png);
stream.Seek(0, SeekOrigin.Begin);
}
imageQRCode.Source = ImageSource.FromStream(() => new MemoryStream(stream));
}