ContentView add GraphicView can display in android and not display in windows ? bug?

Question

<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:drawables="clr-namespace:myMolly.Drawables"
             x:Class="myMolly.Controls.JPScoreView">
    <ContentView.Resources>
        <drawables:JPScoreDrawable x:Key="drawable" />
    </ContentView.Resources>
    <VerticalStackLayout x:Name="vStackLayout">
        <Label Text="ABCD" HorizontalOptions="Center"/>
        <GraphicsView x:Name="gViewPart" HorizontalOptions="Center" Drawable="{StaticResource drawable}"/>
        <Grid x:Name="gridViews"></Grid>
    </VerticalStackLayout>
</ContentView>

graphicview added in contentview,and contentview added in contentpage, that can run correct on android but not display on windows

if graphicview added in contentpage, it can be correct on both

why? bug?

Answer 1

Hello,

I reproduced your problem with the following Drawable, and the reason for this problem is that in ContentView, if you don't set the minimum width and height, in Windows its size is 0.

public class GraphicsDrawable : IDrawable
{
    public void Draw(ICanvas canvas, RectF dirtyRect)
    {
        LinearGradientPaint linearGradientPaint = new LinearGradientPaint
        {
            StartColor = Colors.Yellow,
            EndColor = Colors.Green,
            // StartPoint is already (0,0)
            EndPoint = new Point(1, 0)
        };

       RectF linearRectangle = new RectF(10, 10, 200, 100);
        canvas.SetFillPaint(linearGradientPaint, linearRectangle);
        canvas.SetShadow(new SizeF(10, 10), 10, Colors.Grey);
        canvas.FillRoundedRectangle(linearRectangle, 12);
    }
}

Therefore, you could set MinimumHeightRequest and MinimumWidthRequest to GraphicsView to solve this problem.

<GraphicsView MinimumHeightRequest="300" MinimumWidthRequest="300" x:Name="gViewPart" HorizontalOptions="Center" Drawable="{StaticResource drawable}"/>

Best Regards,

Alec Liu.

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