春节期间，学习了一下UGUI(Unity GUI)。
UGUI是Unity 4.6新增的功能，极大了弥补Unity GUI鸡肋: OnGUI.
学习UGUI最好的途径是系统的推理推理官方的UGUI的demo，如Drag And Drop、Menu 3D、Draggable Panel等，这些非常有嚼头，也可以学到很多东西。
demo很关键：源码，学习的动力，其他都是浮云。
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UGUI原生的UI组件有9个
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EventSystem
交互控件，默认只有一个事件，如Button自带一个OnClick事件，其他的事件，请通过EventTrigger添加。
添加UGUI组件后，一般会自带一个事件，如Button.OnClick()
其他的事件，通过添加Event Trigger添加：
或者通过写脚本，实现17个 UGUI-EventSystem 接口来实现。
- IPointerEnterHandler – OnPointerEnter – Called when a pointer enters the object
- IPointerExitHandler – OnPointerExit – Called when a pointer exits the object
- IPointerDownHandler – OnPointerDown – Called when a pointer is pressed on the object
- IPointerUpHandler – OnPointerUp – Called when a pointer is released (called on the original the pressed object)
- IPointerClickHandler – OnPointerClick – Called when a pointer is pressed and released on the same object
- IInitializePotentialDragHandler – OnInitializePotentialDrag – Called when a drag target is found, can be used to initialise values
- IBeginDragHandler – OnBeginDrag – Called on the drag object when dragging is about to begin
- IDragHandler – OnDrag – Called on the drag object when a drag is happening
- IEndDragHandler – OnEndDrag – Called on the drag object when a drag finishes
- IDropHandler – OnDrop – Called on the object where a drag finishes
- IScrollHandler – OnScroll – Called when a mouse wheel scrolls
- IUpdateSelectedHandler – OnUpdateSelected – Called on the selected object each tick
- ISelectHandler – OnSelect – Called when the object becomes the selected object
- IDeselectHandler – OnDeselect – Called on the selected object becomes deselected
- IMoveHandler – OnMove – Called when a move event occurs (left, right, up, down, ect)
- ISubmitHandler – OnSubmit – Called when the submit button is pressed
- ICancelHandler – OnCancel – Called when the cancel button is pressed
已知问题，在4.6.0 Win 7 64位系统下，ISubmitHandler我添加到InputField上，点击回车不会触发。
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Animation & Animator
UGUI的UI动画，可以由Unity 的新、老动画配合完成。 
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新动画 |
老动画 |
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*.controller |
*.anim |
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Animator状态机 |
Animation录制动画 |
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设置条件变量 |
成对出现 |
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Animator.SetBool() |
Animation.Play() |
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同GameObject |
同GameObject |
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|
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为了简化常用动画，可通过DOTween脚本和UGUI结合，轻松的实现动画。
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3种Canvas的用途
1 Screen Space OverLay 默认模式–静态的
2 Screen Space Camera NGUI默认效果，很酷UI，如ShowDialog等。
3 World Space — 3D对象上用，ToolTip、血条、HUD。
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Layout:Grid\H\V\Element
UGUI提供了4个Layout的组件，同时，结合Rect Transform的Anchors功能，方便设计复杂的UI嵌套。
布局要多练习，其核心思想和Web、流式布局类似，为了考虑多种屏幕尺寸，复杂UI要按照Grid划分好网格，再填充UI元素。
几个Tips：
- Rect Transform Reset ：rectT.anchoredPosition = Vector2.zero; //UGUI
- 一个习惯，把UI的控制代码挂到**Control上独立的一个EmptyGameObject上，如_AudioControl
- 在Image中的九宫格，如果设置Image Type：Sliced后失效，请导出你的场景为UnityPacage，再新建工程导入，则可成功九宫格了。
