using Xamarin.Forms.Internals; namespace Xamarin.Forms.Platform.Android { public class NativeViewWrapperRenderer : ViewRenderer { public override SizeRequest GetDesiredSize(int widthConstraint, int heightConstraint) { if (Element?.GetDesiredSizeDelegate == null) return base.GetDesiredSize(widthConstraint, heightConstraint); // The user has specified a different implementation of GetDesiredSizeDelegate SizeRequest? result = Element.GetDesiredSizeDelegate(this, widthConstraint, heightConstraint); // If the delegate returns a SizeRequest, we use it; if it returns null, // fall back to the default implementation return result ?? base.GetDesiredSize(widthConstraint, heightConstraint); } // not called by the view wrapper renderer protected override global::Android.Views.View CreateNativeControl() { return new global::Android.Views.View(Context); } protected override void OnElementChanged(ElementChangedEventArgs e) { base.OnElementChanged(e); if (e.OldElement == null) { SetNativeControl(Element.NativeView); Control.LayoutChange += (sender, args) => ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); } } protected override void OnLayout(bool changed, int l, int t, int r, int b) { if (Element?.OnLayoutDelegate == null) { base.OnLayout(changed, l, t, r, b); return; } // The user has specified a different implementation of OnLayout bool handled = Element.OnLayoutDelegate(this, changed, l, t, r, b); // If the delegate wasn't able to handle the request, fall back to the default implementation if (!handled) base.OnLayout(changed, l, t, r, b); } protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec) { if (Element?.OnMeasureDelegate == null) { base.OnMeasure(widthMeasureSpec, heightMeasureSpec); return; } // The user has specified a different implementation of OnMeasure bool handled = Element.OnMeasureDelegate(this, widthMeasureSpec, heightMeasureSpec); // If the delegate wasn't able to handle the request, fall back to the default implementation if (!handled) base.OnMeasure(widthMeasureSpec, heightMeasureSpec); } protected override bool ManageNativeControlLifetime => false; } }