（unity和C#）Event

简介

实例

• 简单调用

  using UnityEngine;
  
  public class DelegateExample : MonoBehaviour {
      //Step1. 定义类型----为Delegate定义一种函数原型
      public delegate void MyDelegate(int args);
      //Step2. 声明变量----声明一个Delegate变量
      public MyDelegate myDelegate;
  
      private void Start()
      {
          //Step3. 变量赋值----引用Delegate变量实现相应的函数
          myDelegate = PrintNum;
          myDelegate(5);
      }
  
      public void PrintNum(int num)
      {
          print("Print number: " + num);
      }
  }
  

• C# Event

  把Event想象成一个视频作者，并且他还具有一大堆热情的粉丝，每天都在等待新视频的发布。为了在第一时间收看到新发布的视频，粉丝们大多会选择订阅视频作者，这样作者更新时你就会收到一条即时消息。event只负责告诉每个函数什么时候被调用，这些函数到底干了什么，event并不关心

  //Idol.cs 广播消息 定义的event相当于源头，只要调用了该事件，都会引起注册该事件的人调用相应的注册方法
  public class Idol : MonoBehaviour {
      public delegate void IdolBehaviour(string behaviour);
      public static event IdolBehaviour IdolDoSomethingHandler;
  
      private void Start()
      {
          //Idol 决定搞事了, 如果他还有粉丝的话, 就必须全部都通知到
          if (IdolDoSomethingHandler != null)
          {
              IdolDoSomethingHandler("Idol give up writing.");
          }
      }
  }
  

  //SubscriberA.cs  订阅消息 很早注册订阅了，当event发送了，那么就会调用对应方法
  public class SubscriberA : MonoBehaviour {
      private void OnEnable()
      {
          //注册事件 相当于偶像突然有什么事件了，就会立即知道
          Idol.IdolDoSomethingHandler += LikeIdol;
      }
  
      //取消注册 
      private void OnDisable()
      {
          Idol.IdolDoSomethingHandler -= LikeIdol;
      }
  
      /// 粉丝A是一个脑残粉
      public void LikeIdol(string idolAction)
      {
          print(idolAction + " I will support you forever!");
      }
  }
  

• Unity Event

  主要是可以拖拽很方便，用Serializable序列化IdolEvent，这样可以在Editor中显示

  //Idol.cs 需要的event直接继承自UnityEvent
  using UnityEngine;
  using UnityEngine.Events;
  
  //使用Serializable序列化IdolEvent, 否则无法在Editor中显示
  [System.Serializable]
  public class IdolEvent : UnityEvent<string> {
  
  }
  
  public class Idol : MonoBehaviour {
      public IdolEvent idolEvent;
      private void Start()
      {
          //Idol 广播消息
          if (idolEvent == null)
          {
              idolEvent = new IdolEvent();
          }
          idolEvent.Invoke("Idol give up writing.");
      }
  }
  

  //SubscriberA.cs  如果通过拖拽，只需要写个方法即可
  //不通过拖拽 也可以注册 Addlistener
  using UnityEngine;
  public class SubscriberB : MonoBehaviour {
      public Idol myIdol;
      private void OnEnable()
      {
          //注册事件
          myIdol.idolEvent.AddListener(HateIdol);
      }
  
      private void OnDisable()
      {
          myIdol.idolEvent.RemoveListener(HateIdol);
      }
  
      public void HateIdol(string idolAction)
      {
          print(idolAction + " I will hate you forever!");
      }
  }
  

• C# Action+Unity Action

  其实是封装好的委托

  //Data.cs 定义委托，值改变给委托
  using UnityEngine;
  using System.Collections;
  
  public class Data {
    public System.Action<int, int> onDataChange;
      public UnityAction<int, int> onDataChange1;
  
      public int blood { get; set; }
      public int blue { get; set; }
  
      public Data()
      {
  
      }
  
      public void SetData(int blood, int blue)
      {
          this.blood = blood;
          this.blue = blue;
          onDataChange(this.blood, this.blue);
          onDataChange1(this.blood, this.blue);
      }
  }
  

  //Test.cs 可以UI显示  
  public class Test : MonoBehaviour
  {
      private Data _Data;
      private void Start()
      {
          _Data = new Data();
          _Data.onDataChange += ChangeView;
          _Data.onDataChange1 += ChangeView;
      }
  
      private void ChangeView(int a,int b)
      {
          Debug.LogError(a);
      }
  
      void Update()
      {
          _Data.SetData(1, 2);
      }
  }
  

• Unity Event+Action

  • action是委托，可以注册很多方法
  • event是事件，能够注册方法，也能action
  • event的Invoke()方法可以一次性调用所有UnityAction

  //不带参数UnityEvent不是抽象类，可以直接实例化
  using UnityEngine;
  using System.Collections;
  using UnityEngine.Events;
   
  public class UnityActionAndEvent : MonoBehaviour
  {
      public UnityAction action;
      public UnityEvent myEvent = new UnityEvent();
   
      void Start()
      {
          action = new UnityAction(MyFunction);
          action += MyFunction2;
          myEvent.AddListener(action);
      }
   
      void Update()
      {
          if (Input.GetKeyDown(KeyCode.P))
          {
              myEvent.Invoke();
          }
      }
   
      public void MyFunction()
      {
          print("Hello: ");
      }
   
      public void MyFunction2()
      {
          print("Hello2: ");
      }
  }
  
  //带参数UnityEvent是抽象类，需要自己声明一个类
  public class MyEvent:UnityEvent<int>{}
  
  public class UnityActionWithParameter : MonoBehaviour {
      public MyEvent myEvent = new MyEvent();
      public UnityAction<int> action;
   
      void Start () {
          action= new UnityAction<int>(MyFunction);
          action += MyFunction2;
          myEvent.AddListener(action);
      }  
   
      void Update () {
          if(Input.GetKeyDown(KeyCode.A))
          {
              myEvent.Invoke(10);
          }
      }
   
      public void MyFunction(int i)
      {
          print (i);
      }
      public void MyFunction2(int i)
      {
          print(i*2);
      }
  }
  

• 其他事件（button.onClick等，通过Addlistener添加Action，Action可以注册多个方法）

  using UnityEngine;
  using UnityEngine.UI;
  using UnityEngine.Events;
  
  public class UnityActionExample : MonoBehaviour
  {
      Button m_AddButton;
      Renderer m_Renderer;
  
      private UnityAction m_MyFirstAction;
      float m_MyNumber;
  
      void Start()
      {
          m_AddButton = GetComponent<Button>();
          m_Renderer = GetComponent<Renderer>();
  
          m_MyFirstAction += MyFunction;
          m_MyFirstAction += MySecondFunction;
  
          m_AddButton.onClick.AddListener(m_MyFirstAction);
      }
  
      void MyFunction()
      {
          m_MyNumber++;
          Debug.Log("First Added : " + m_MyNumber);
      }
  
      void MySecondFunction()
      {
          m_Renderer.material.color = Color.blue;
          Debug.Log("Second Added");
      }
  }
  

参考

https://blog.csdn.net/qq_28849871/article/details/78366236

https://docs.unity3d.com/ScriptReference/Events.UnityAction.html