UGUI事件触发代码

may

//14.事件实例解析---------------------------------------------------------------------------------------------
UGUI中 事件触发分为:被动触发,主动触发


示例: Button组件怎么触发按钮事件?

public class Button : Selectable, IPointerClickHandler, ISubmitHandler
{...}
按钮组件继承了Selectable类;实现了点击事件,提交事件.


源码:

1. //按钮类 Button.cs
   
2.        
   
3. // Event delegates triggered on click.
   
4. [FormerlySerializedAs("onClick")]
   
5. [SerializeField]
   
6. private ButtonClickedEvent m_OnClick = new ButtonClickedEvent();
   
7. 
   
8. // Trigger all registered callbacks.
   
9. public virtual void OnPointerClick(PointerEventData eventData)
   
10. {
    
11.         if (eventData.button != PointerEventData.InputButton.Left)
    
12.                 return;
    
13. 
    
14.         Press();//如果点击了鼠标左键,说明按钮被按了
    
15. }
    
16. 
    
17. private void Press()
    
18. {
    
19.         if (!IsActive() || !IsInteractable())
    
20.                 return;
    
21. 
    
22.         m_OnClick.Invoke(); //如果按钮显示着,并且允许进行交互,就执行按钮点击事件处理函数
    
23. }
    
24. 
    
25. 
    
26. public virtual void OnSubmit(BaseEventData eventData)
    
27. {
    
28.         Press();
    
29. 
    
30.         // if we get set disabled during the press
    
31.         // don't run the coroutine. 如果我们的按钮是禁用的,则不响应这个协程
    
32.         if (!IsActive() || !IsInteractable())
    
33.                 return;
    
34. 
    
35.         DoStateTransition(SelectionState.Pressed, false);//设置按钮不再处于按下状态
    
36.         StartCoroutine(OnFinishSubmit());  //执行按钮被点击后的事情
    
37. }
    
38. 
    
39. private IEnumerator OnFinishSubmit()
    
40. {
    
41.         var fadeTime = colors.fadeDuration;
    
42.         var elapsedTime = 0f;
    
43. 
    
44.         while (elapsedTime < fadeTime)
    
45.         {
    
46.                 elapsedTime += Time.unscaledDeltaTime;
    
47.                 yield return null;
    
48.         }
    
49. 
    
50.         DoStateTransition(currentSelectionState, false);
    
51. }

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其他组件事件实现也类似.

UGUI官方相关示例: Drag and drop
拖 DragMe.cs
放 DropMe.cs

public class DragMe : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{...}

public class DropMe : MonoBehaviour, IDropHandler, IPointerEnterHandler, IPointerExitHandler
{...}