求助：将旧NGUI相机旋转事件代码适配Unity新UI（Canvas）

问题描述 #

我从网上下载了一款控制器，但其UI采用旧版NGUI方法开发。这段代码用于实现相机旋转功能，我无法理解其中的EventListeners逻辑，恳请帮助将Awake函数改造为Unity新UI（Canvas）的写法。

原NGUI代码 #

private void Awake()
{
    UIEventListener uIEventListener = rotateAreaBtn;
    uIEventListener.onPress = (UIEventListener.BoolDelegate)Delegate.Combine(uIEventListener.onPress, new UIEventListener.BoolDelegate(OnPressArea));
    UIEventListener uIEventListener2 = rotateAreaBtn;
    uIEventListener2.onDrag = (UIEventListener.VectorDelegate)Delegate.Combine(uIEventListener2.onDrag, new UIEventListener.VectorDelegate(OnDragCam));
}

public void OnDragCam(GameObject obj, Vector2 deta)
{
    dragDeta = deta;
    isDrag = true;
    PlayerController.instance.fireTarget = null;
    if (PlayerController.instance.curState == PLAYERSTATE.FIGHT)
    {
        PlayerController.instance.ChangeState(PLAYERSTATE.NORMAL);
    }
    else if (PlayerController.instance.curState != PLAYERSTATE.CAR && (PlayerController.instance.animaCtl.isAimFlag || PlayerController.instance.animaCtl.needToAimFlag))
    {
        PlayerController.instance.ChangeState(PlayerController.instance.curState);
    }
}

public void OnPressArea(GameObject obj, bool press)
{
    isPress = press;
    if (!press)
    {
        dragDeta = Vector2.zero;
    }
}

改造为Unity新UI的实现 #

Unity新UI（UGUI）使用标准事件接口替代NGUI的UIEventListener，以下是改造后的完整代码：

using UnityEngine;
using UnityEngine.EventSystems;

public class CameraRotateController : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IDragHandler
{
    // 若旋转区域是单独的UI对象，可保留此引用；否则直接将脚本挂载到旋转区域UI上即可
    // public GameObject rotateAreaBtn;

    private Vector2 dragDeta;
    private bool isPress;
    private bool isDrag;

    // 按下UI时触发
    public void OnPointerDown(PointerEventData eventData)
    {
        OnPressArea(gameObject, true);
    }

    // 抬起UI时触发
    public void OnPointerUp(PointerEventData eventData)
    {
        OnPressArea(gameObject, false);
    }

    // 拖拽UI时触发
    public void OnDrag(PointerEventData eventData)
    {
        OnDragCam(gameObject, eventData.delta);
    }

    // 原拖拽逻辑保留不变
    public void OnDragCam(GameObject obj, Vector2 deta)
    {
        dragDeta = deta;
        isDrag = true;
        PlayerController.instance.fireTarget = null;
        if (PlayerController.instance.curState == PLAYERSTATE.FIGHT)
        {
            PlayerController.instance.ChangeState(PLAYERSTATE.NORMAL);
        }
        else if (PlayerController.instance.curState != PLAYERSTATE.CAR && (PlayerController.instance.animaCtl.isAimFlag || PlayerController.instance.animaCtl.needToAimFlag))
        {
            PlayerController.instance.ChangeState(PlayerController.instance.curState);
        }
    }

    // 原按下/抬起逻辑保留不变
    public void OnPressArea(GameObject obj, bool press)
    {
        isPress = press;
        if (!press)
        {
            dragDeta = Vector2.zero;
        }
    }
}

关键逻辑说明 #

• 原NGUI的UIEventListener.onPress对应新UI的IPointerDownHandler（按下）和IPointerUpHandler（抬起）接口，通过两个方法分别触发按下/抬起状态
• 原NGUI的UIEventListener.onDrag对应新UI的IDragHandler接口，eventData.delta就是拖拽的增量偏移，和原代码的deta参数功能一致
• 无需再在Awake中手动绑定事件，只要类实现对应的接口，Unity会自动处理事件监听
• 确保场景中存在EventSystem对象（创建Canvas时Unity会自动生成，若缺失需手动添加）

内容的提问来源于stack exchange，提问作者Abdul Rehman