Benutzer:MovGP0/Xamarin/Custom Renderer
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Custom Renderer[Bearbeiten | Quelltext bearbeiten]PCL or Shared Project[Bearbeiten | Quelltext bearbeiten]using Xamarin.Forms;
// derives from BindableObject
public sealed class RoundedBoxView : BoxView
{
public static readonly BindableProperty CornerRadiusProperty =
BindableProperty.Create(nameof(CornerRadius), typeof(double), typeof(RoundedBoxView), 0.0);
public double CornerRadius
{
get { return (double)GetValue(CornerRadiusProperty); }
set { SetValue(CornerRadiusProperty, value); }
}
public static readonly BindableProperty StrokeProperty =
BindableProperty.Create(nameof(StrokeRadius), typeof(Color), typeof(RoundedBoxView), Colors.Transparent);
public Color Stroke
{
get { return (Color)GetValue(StrokeProperty); }
set { SetValue(StrokeProperty, value); }
}
public static readonly BindableProperty StrokeThicknessProperty =
BindableProperty.Create(nameof(StrokeThickness), typeof(double), typeof(RoundedBoxView), 1.0);
public double StrokeThickness
{
get { return (double)GetValue(StrokeThicknessProperty); }
set { SetValue(StrokeThicknessProperty, value); }
}
}
<ContentPage xmlns:local="clr-namespace:NAMESPACE;assembly=ASSEMBLYNAME">
<local:RoundedBoxView CornerRadius="5" StrokeThickness="3" Stroke="Red" />
</ContentPage>
WPF/UWP[Bearbeiten | Quelltext bearbeiten]Android[Bearbeiten | Quelltext bearbeiten]using System;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Android.Graphics;
[assembly: ExportRendererAttribute(typeof(RoundedBoxView), typeof(RoundedBoxViewRenderer))]
namespace MyApp.Android
{
// derives from VisualElementRenderer<BoxView>
// derives from Android.Views.View
public class RoundedBoxViewRenderer : BoxRenderer
{
public RoundedBoxViewRenderer()
{
SetWillNotDraw(false);
}
public override void Draw(Canvas canvas)
{
var view = (RoundedBoxView)Element;
var boundary = new Rect();
GetDrawingRect(boundary);
boundary.Inset((int)view.StrokeThickness, (int)view.StrokeThickness);
var fillPaint = new Paint
{
Color = view.Color.ToAndroid(),
AntiAlias = true
};
canvas.DrawRoundRect(new RectF(boundary), (float)view.CornerRadius, (float)view.CornerRadius, fillPaint);
var borderPaint = new Paint
{
Color = view.Stroke.ToAndroid(),
StrokeWidth = (float)view.StrokeThickness,
AntiAlias = true
};
borderPaint.SetStyle(Paint.Style.Stroke);
canvas.DrawRoundRect(new RectF(boundary), (float)view.CornerRadius, (float)view.CornerRadius, borderPaint);
// base.Draw(canvas);
}
}
}
iOS[Bearbeiten | Quelltext bearbeiten]
using System;
using System.ComponentModel;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;
using MonoTouch.CoreLocation;
[assembly: ExportRendererAttribute(typeof(RoundedBoxView), typeof(RoundedBoxViewRenderer))]
namespace MyApp.iOS
{
// derives from VisualElementRenderer<BoxView>
// derives from UIView
public class RoundedBoxViewRenderer : BoxRenderer
{
public override void Draw(RectangleF rect)
{
var view = (RoundedBoxView)Element;
using(context = UIGraphics.GetCurrentContext()){
context.SetFillColor(view.Color.ToCGColor());
context.SetStrokeColor(view.Stroke.ToCGColor());
context.SetLineWidth(view.StrokeThickness);
var boundary = Bounds.Inset((int)view.StrokeThickness, (int)view.StrokeThickness);
var cornerRadius = (float)view.CornerRaduis;
var radius = Math.Max(0f, Math.Min(cornerRadius), Math.Max(boundary.Height/2f, boundary.Width/2f)));
var path = CGPath.FromRoundedRect(boundary, raduis, radius);
context.AddPath(path);
context.Draw(CGPathDrawingMode.FillStroke);
}
}
public override void OnElementPropertyChanged(object sender, PreopertyChangedEventArgs args)
{
base.OnElementPropertyChanged(sender, args);
if(args.PropertyName == RoundedBoxView.CornerRadiusProperty.PropertyName
|| args.PropertyName == RoundedBoxView.StrokeProperty.PropertyName
|| args.PropertyName == RoundedBoxView.StrokeThicknessProperty.PropertyName)
{
SetNeedsDisplay();
}
}
}
}
using System;
using System.ComponentModel;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;
using MonoTouch.CoreLocation;
[assembly: ExportRendererAttribute(typeof(RoundedBoxView), typeof(RoundedBoxViewRenderer))]
namespace MyApp.iOS
{
public class RoundedBoxViewRenderer : ViewRenderer<RoundedBoxView, UIView>
{
public override void OnElementChanged(object sender, PreopertyChangedEventArgs args)
{
base.OnElementChanged(args);
var view = e.NewElement;
if(view == null) return;
var shadowView = new UIView();
var childView = new UIView
{
BackgroundColor = view.Color.ToUIColor(),
Layer = {
CornerRadius = (float) view.CornerRadius,
BorderColor = view.Stroke.ToCGColor(),
BorderWidth = view.StrokeThickness,
MasksToBounds = true
},
AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight
};
shadowView.Add(childView);
if(view.HasShadow)
{
RenderShadow(shadowView);
}
SetNativeControl(shadowView);
}
private void RenderShadow(View shadowView)
{
shadowView.Layer.ShadowColor = UIColor.Black.CGColor,
shadowView.Layer.ShadowOffset = new SizeF(3,3);
shadowView.Layer.ShadowOpacity = 1;
shadowView.Layer.ShadowRaduis = 5;
}
private void RenderNoShadow(View shadowView)
{
shadowView.Layer.ShadowColor = UIColor.Clear.CGColor,
shadowView.Layer.ShadowOffset = new SizeF();
shadowView.Layer.ShadowOpacity = 0;
shadowView.Layer.ShadowRaduis = 0;
}
public override void OnElementPropertyChanged(object sender, PreopertyChangedEventArgs args)
{
base.OnElementPropertyChanged(sender, args);
if(args.PropertyName == RoundedBoxView.CornerRadiusProperty.PropertyName)
{
childView.Layer.CornerRadius = (float)Element.CornerRadius;
}
else if(args.PropertyName == RoundedBoxView.StrokeProperty.PropertyName)
{
childView.Layer.BorderColor = Element.Stroke.ToCGColor();
}
else if(args.PropertyName == RoundedBoxView.StrokeThicknessProperty.PropertyName)
{
childView.Layer.BorderWidth = (float)Element.StrokeThickness;
}
else if(args.PropertyName == RoundedBoxView.ColorProperty.PropertyName)
{
childView.BackgroundColor = Element.Color.ToUIColor();
}
else if(args.PropertyName == RoundedBoxView.HasShadowProperty.PropertyName)
{
if(Element.HasShadow)
{
RenderShadow(NativeView);
}
else
{
RenderNoShadow(NativeView);
}
}
}
}
}
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