UI组件添加点击事件的四种方法

UI组件添加点击事件的四种方法

1、添加UGUI自带的Button组件，给Button添加OnClick()点击事件；

2、获取Button组件，调用onClick的AddListener（）方法：

        this.transform.GetComponent<Button>().onClick.AddListener(()=> {

            //what to do ...

        });

3、通过 MonoBehaviour 实现事件类接口来实现事件的监听 #

Step 1 : 通过 Hierarchy 面板创建 UI > Button.

Step 2 : 创建一个 EventHandler.cs 脚本.

Step 3 : 将脚本绑定在 Button 对象上.

Step 4 : Done.

EventHandler.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
 
public class EventHandler : MonoBehaviour, IPointerClickHandler, IPointerEnterHandler, IPointerExitHandler, IPointerDownHandler, IDragHandler {
 
    public void OnPointerClick(PointerEventData eventData){
        if(eventData.pointerId == -1){
            Debug.Log ("Left Mouse Clicked.");
        } else if(eventData.pointerId == -2){
            Debug.Log ("Right Mouse Clicked.");
        }
    }
 
    public void OnPointerEnter(PointerEventData eventData){
        Debug.Log ("Pointer Enter..");
    }
 
    public void OnPointerExit(PointerEventData eventData){
        Debug.Log ("Pointer Exit..");
    }
 
    public void OnPointerDown(PointerEventData eventData){
        Debug.Log ("Pointer Down..");
    }
 
    public void OnDrag(PointerEventData eventData){
        Debug.Log ("Dragged..");
    }
 
}

UGUI 如何判断 UI 元素被点击时是鼠标的哪个按键, 上面的代码中我们可以根据 eventData.pointerId 来监听是鼠标左键还是右键. 但是每个 UI 元素都创建一个 MonoBehaviour 来监听各个事件显然不好, 下面是通过利用 Delegate 和 Event 来做一个通用类 UIEventListener 来处理事件 (观察者模式).

UIEventListener.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
 
public class UIEventListener : MonoBehaviour, IPointerClickHandler, IPointerEnterHandler, IPointerExitHandler {
 
    // 定义事件代理
    public delegate void UIEventProxy(GameObject gb);
 
    // 鼠标点击事件
    public event UIEventProxy OnClick;
 
    // 鼠标进入事件
    public event UIEventProxy OnMouseEnter;
 
    // 鼠标滑出事件
    public event UIEventProxy OnMouseExit;
 
    public void OnPointerClick(PointerEventData eventData){
        if (OnClick != null)
            OnClick (this.gameObject);
    }
 
    public void OnPointerEnter(PointerEventData eventData){
        if (OnMouseEnter != null)
            OnMouseEnter (this.gameObject);
    }
 
    public void OnPointerExit(PointerEventData eventData){
        if (OnMouseExit != null)
            OnMouseExit (this.gameObject);
    }
 
}

TestEvent.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
 
public class TestEvent : MonoBehaviour {
 
    void Start () {
        Button btn = this.GetComponent<Button> ();
        UIEventListener btnListener = btn.gameObject.AddComponent<UIEventListener> ();
 
        btnListener.OnClick += delegate(GameObject gb) {
            Debug.Log(gb.name + " OnClick");
        };
 
        btnListener.OnMouseEnter += delegate(GameObject gb) {
            Debug.Log(gb.name + " OnMouseEnter");
        };
 
        btnListener.OnMouseExit += delegate(GameObject gb) {
            Debug.Log(gb.name + " OnMOuseExit");
        };
    }
 
}

TestEvent 脚本绑定在 Button 上即可.

4、

通过 EventTrigger 实现按钮点击事件 #

UGUI 系统中 Button 默认只提供了 OnClick 的调用方法, 有时候我们还需要监听鼠标进入事件 (MouseIn) 和鼠标滑出事件 (MouseOut). 就需要借助 UI 系统中的 EventTrigger 脚本来实现.

Step 1 : 通过 Hierarchy 面板创建 UI > Button.

Step 2 : 创建一个 EventTriggerHandler.cs 脚本, 利用 UnityEngine.EventSystems.EventTrigger 添加监听事件.

Step 3 : 绑定 EventTriggerHandler.cs 脚本到 Button 上.

Step 4 : Done.

EventTriggerHandler.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
 
// 需要 EventTrigger 脚本的支援
[RequireComponent(typeof(UnityEngine.EventSystems.EventTrigger))]
public class EventTriggerHandler : MonoBehaviour {
 
    // Use this for initialization
    void Start () {
        Button btn = this.GetComponent<Button> ();
        EventTrigger trigger = btn.gameObject.GetComponent<EventTrigger> ();
        EventTrigger.Entry entry = new EventTrigger.Entry ();
        // 鼠标点击事件
        entry.eventID = EventTriggerType.PointerClick;
        // 鼠标进入事件 entry.eventID = EventTriggerType.PointerEnter;
        // 鼠标滑出事件 entry.eventID = EventTriggerType.PointerExit;
        entry.callback = new EventTrigger.TriggerEvent ();
        entry.callback.AddListener (OnClick);
        // entry.callback.AddListener (OnMouseEnter);
        trigger.triggers.Add (entry);
    }
 
    private void OnClick(BaseEventData pointData){
        Debug.Log ("Button Clicked. EventTrigger..");
    }
 
    private void OnMouseEnter(BaseEventData pointData){
        Debug.Log ("Button Enter. EventTrigger..");
    }
}

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