OK. Thanks to the posts above, I managed to get this working so I thought I'd post code for anyone having issues in the future. Remember, this is solely around the display of a barcode NOT the scanning!
I added ZXing.Net.Mobile to my Droid and iOS projects. I didn't need to add it to my core Forms project.
In my core Forms project I had an image in XAML:
<Image Grid.Row="13" Grid.ColumnSpan="2" Source="{Binding BarcodeImageSource}" HorizontalOptions="Center" WidthRequest="300" HeightRequest="130"/>
On my view model I had:
public ImageSource BarcodeImageSource { get;set;}
....
// this will set the image source for the BarcodeImageSource property which the Image in XAML will pick up
var stream = this.barcodeService.ConvertImageStream(result.CardId);
this.BarcodeImageSource = ImageSource.FromStream(() => {return stream; });Ok that bit of code 'this.barcodeService.ConvertImageStream(result.CardId);' had to use dependency injection to have Droid and iOS specific code. The ZXing code is the same in both cases. It's actually the code for writing the bitmap to a stream that is platform specific.
So I have my interface:
using System;
using System.IO;
namespace MyApp.Services
{
public interface IBarcodeService
{
Stream ConvertImageStream(string text, int width = 300, int height=130);
}
}Then Android implementation:
using Android.Graphics;
using MyApp.Services
using System;
using System.IO;
using ZXing.Mobile;
namespace MyApp.Android
{
public class BarcodeService : IBarcodeService
{
public Stream ConvertImageStream(string text,int width = 300, int height=130)
{
var barcodeWriter = new ZXing.Mobile.BarcodeWriter {
Format = ZXing.BarcodeFormat.CODE_39,
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;
}
}
}And the iOS implementation.
using System;
using System.Drawing;
using System.IO;
using Xamarin.Forms;
using MyApp.Services;
using UIKit;
using CoreGraphics;
using ZXing.Mobile;
namespace MyApp.iOS
{
public class BarcodeService : IBarcodeService
{
public Stream ConvertImageStream(string text,int width = 300, int height=130)
{
var barcodeWriter = new ZXing.Mobile.BarcodeWriter {
Format = ZXing.BarcodeFormat.CODE_39,
Options = new ZXing.Common.EncodingOptions {
Width = width,
Height = height,
Margin = 10
}
};
barcodeWriter.Renderer = new ZXing.Mobile.BitmapRenderer();
var bitmap = barcodeWriter.Write(text);
var stream = bitmap.AsPNG().AsStream(); // this is the difference
stream.Position = 0;
return stream;
}
}
}