可拖动的CALayer [英] Draggable CALayer

问题描述

有什么方法可以使用户拖动CALayer？如果是，怎么办？

Any way of making a CALayer draggable by the user? If so, how?

（在Cocoa-Mac中）

(In Cocoa - Mac)

推荐答案

图层本身无法接收鼠标事件。您必须在包含图层的视图或视图控制器中进行事件处理。

Layers can not receive mouse events themselves. You would have to do the event handling in the view or view controller containing the layer.

如果 mouseDragged：事件起源于一层（请参见-[CALayer hitTest：] 和-[CALayer containsPoint：] 进行测试） ，相应地调整图层的位置。您可能要禁用隐式动画，以使图层立即跟随鼠标指针（而不是由于position属性的动画而滞后一点）：

If a mouseDragged: event originates on a layer (see -[CALayer hitTest:] and -[CALayer containsPoint:] to test this), adjust the layer's position accordingly. You will probably want to disable implicit animations to have the layer follow the mouse pointer immediately (rather than lagging a little behind because of the animation of the position property):

[CATransaction begin];
[CATransaction setDisableActions:YES];
layer.position = ...;
[CATransaction commit];

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