ios - 自定义类型的 UIButton 丢失 Click 事件

Question

我有以下代码在 Xamarin 中创建自定义 iOS UIButton:

    protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
    {
        // will have to create a native Custom type of ios button to avoid text dimming
        // when touched

        // logic of element processing from
        // https://developer.xamarin.com/guides/xamarin-forms/custom-renderer/view/

        // except we don't call the base immediately
        // because it will create the Control for us, but we don't want that here
        if (Control == null)
        {
            // instantiate the native control and assign it to the Control property with
            // the SetNativeControl method
            uiBtn = new UIButton(UIButtonType.Custom);
            SetNativeControl(uiBtn); // should set Control to the newly created element 
            // and prevent base.OnElementChanged(e) from creating a new element instead
        }

        base.OnElementChanged(e);

        // some button customization code here - it does not matter, the issue happens also without it...

渲染器代码工作正常，但现在我的 Xamarin.Forms 按钮上没有收到任何 Clicked 事件。

如何恢复丢失的点击功能？

Answer 1

最后在 Xamarin 源代码中我发现了这个:

https://github.com/xamarin/Xamarin.Forms/blob/2d9288eee6e6f197364a64308183725e7bd561f9/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs

看着 OnElementChanged 我有点惊讶，只有当 OnElementChanged 的​​这个实例创建 native 元素时才会附加事件。不确定为什么要这样做，但至少现在我知道如果我自己创建一个控件，那么我还必须自己连接点击事件。