ios - CATiledLayer、CALayerDelegate 和捕获触摸事件

Question

我将如何捕获 CATiledLayer 上的触摸事件？

我遇到以下情况，如果我将 View 层更改为 CATiledLayer， View 将停止捕获 TouchesXXX 事件。为什么会发生这种情况，我应该如何解决这个问题。

public partial class DocumentView : UIView
{
    public DocumentView ()
    {
        //if the following lines are removed touch events are captured
        //otherwise they are not
        var tiledLayer = Layer as CATiledLayer;
        tiledLayer.Delegate = new TiledLayerDelegate (this);
    }

    public override void TouchesBegan (NSSet touches, UIEvent evt)
    {
        //does not get called if we hook TiledLayerDelegate up there in the construct  
        base.TouchesBegan (touches, evt);
    }
}

public class TiledLayerDelegate : CALayerDelegate
{
    public DocumentView DocumentView;

    public TiledLayerDelegate (DocumentView documentView)
    {
        DocumentView = documentView;
    }

    public override void DrawLayer (CALayer layer, CGContext context)
    {
        //draw happens here
    }
}

Answer 1

我真的不知道这是什么原因。但是，我用两种不同的方式让它工作:

1. 通过将层的默认类型保留为 CALayer，创建一个新的 CATiledLayer 并将其作为子层添加到 View 的 Layer。我想这不是一个合适的解决方案。

2. 通过使用 WeakDelegate，而不是强类型的 Delegate。将以下内容放入您的 View 子类中:

   [导出("drawLayer:inContext:")]

   public void DrawLayer(CALayer layer, CGContext context)
   {
       //draw happens here 
   }
   

并更改以下行

tiledLayer.Delegate = new TiledLayerDelegate (this);

到:

tiledLayer.WeakDelegate = this;