Unity—鼠标/手指是否点击UI及相关类的总结

转载自：雨松MOMO 2014年10月27日 于 雨松MOMO程序研究院 发表

http://www.xuanyusong.com/archives/3327

UI和3D场景同时都需要响应触摸事件，如果同时响应可能就会出现触摸UI的时候影响到了3D部分。为了解决这个问题在判断3D响应之前要先判断手指是否点击在UI上：

UGUI 提供了一个检测是否点击在UI上的方法 ：EventSystem.current.IsPointerOverGameObject();

#if UNITY_ANDROID && !UNITY_EDITOR
#define ANDROID
#endif
 
 
#if UNITY_IPHONE && !UNITY_EDITOR
#define IPHONE
#endif
 
 
 
using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using UnityEngine.EventSystems;
public class NewBehaviourScript : MonoBehaviour {
 
    // Use this for initialization
    void Start () {
    
    }
    
 
    void Update()
    {
        if (Input.GetMouseButtonDown(0)||(Input.touchCount >0 && Input.GetTouch(0).phase == TouchPhase.Began))
        {
#if IPHONE || ANDROID
            if (EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
#else
            if (EventSystem.current.IsPointerOverGameObject())
#endif
                Debug.Log("当前触摸在UI上");
            
            else 
                Debug.Log("当前没有触摸在UI上");
        }
    }
}

IsPointerOverGameObject()：

              public bool IsPointerOverGameObject();

                public bool IsPointerOverGameObject(int pointerId);

Parameters/参数

       

pointerId
Pointer (touch / mouse) ID.

Description/描述

Is the pointer with the given ID over an EventSystem object?/所给ID点上是否存在EventSystem 物体

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;

public class MouseExample : MonoBehaviour
{
    void Update()
    {
        // Check if the left mouse button was clicked
        if (Input.GetMouseButtonDown(0))
        {
            // Check if the mouse was clicked over a UI element
            if (EventSystem.current.IsPointerOverGameObject())
            {
                Debug.Log("Clicked on the UI");
            }
        }
    }
}

If you use IsPointerOverGameObject() without a parameter, it points to the "left mouse button" (pointerId = -1); therefore when you use IsPointerOverGameObject for touch, you should consider passing a pointerId to it.

/如果你使用不带参数的IsPointerOverGameObject()方法，默认指鼠标左键；因此当你想在触摸屏中使用IsPointerOverGameObject()方法，你应该为它顺便指定个参数。

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;

public class TouchExample : MonoBehaviour
{
    void Update()
    {
        // Check if there is a touch
        if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)
        {
            // Check if finger is over a UI element
            if (EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
            {
                Debug.Log("Touched the UI");
            }
        }
    }
}

Note that for touch, IsPointerOverGameObject should be used with OnMouseDown() or Input.GetMouseButtonDown(0) or Input.GetTouch(0).phase == TouchPhase.Began.

#if IPHONE || ANDROID
            if (EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
#else
            if (EventSystem.current.IsPointerOverGameObject())
#endif
               。。。。。。

——这里#if #else #endif，功能叫平台依赖编译（Platform Dependent Compilation），判断当前所在平台，从而调用相应code;

官方API:https://docs.unity3d.com/Manual/PlatformDependentCompilation.html