Question

如何在CATiledLayer上捕获触摸事件？

我有以下情况，如果我将视图层更改为CATiledLayer，视图将停止捕获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使它工作：

将图层的默认类型保留为CALayer，创建新的CATiledLayer并将其作为子图层添加到视图的Layer。我想这不是一个合适的解决方案。
使用WeakDelegate代替强类型Delegate。将以下内容放在视图子类中：

[导出（ “drawLayer：inContext的：”）]
```
public void DrawLayer(CALayer layer, CGContext context)
{
    //draw happens here 
}
```

并更改以下行

tiledLayer.Delegate = new TiledLayerDelegate (this);

为：

tiledLayer.WeakDelegate = this;

CATiledLayer，CALayerDelegate和捕获触摸事件

1 个答案: