PointerEventData.pointerPressRaycast

描述

返回与鼠标单击、游戏手柄按钮按下或屏幕触摸相关联的 RaycastResult。

当游戏请求玩家按下详情时，PointerEventData.pointerPressRaycast 返回 RaycastResult 命中结果。

以下示例使用 IDragHandler、IDragHandler 和 IEndDragHandler 接口。这些接口分别提供 OnDrag、OnDrag 和 OnEndDrag 事件处理程序。当射线投射命中世界空间中的某个点时，OnBeginDrag 将进行查询。OnBeginDrag 将消息发送到 PointerEventData.pointerPressRaycast.worldPosition。然后代码示例报告 OnBeginDrag 启动时的屏幕位置。

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

// PointerEventData.pointerPressRaycast example

// A cube which can be moved by the mouse or track bar at runtime.
// Up/down and left/right are supported.
//
// Create a 3D project and add a Cube. Position the Cube at the origin. Add a
// PhysicsRaycaster component to the Main Camera. Also, add an Empty GameObject
// to the Hierarchy. Apply an EventSystem component and a StandaloneInputModule
// component to this Empty GameObject. Next create this script and assign it to
// the Cube. Now, run the Game. The Cube can be moved up/down and left/right.

public class Example : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private Vector3 newPosition;
    private Vector3 delta;
    private Vector3 startPosition;

    void Awake()
    {
        // Move the Cube away from the origin.
        startPosition = new Vector3(0.25f, -0.5f, 3.0f);
        transform.position = startPosition;

        newPosition = Vector3.zero;
        delta = Vector2.zero;

        // Position the camera and switch to solid color.
        Camera.main.transform.position = new Vector3(0.5f, 1.0f, -3.0f);
        Camera.main.transform.localEulerAngles = new Vector3(15.0f, -20.0f, 0.0f);
        Camera.main.clearFlags = CameraClearFlags.SolidColor;
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        Debug.Log("OnBeginDrag: " + eventData.pointerPressRaycast.screenPosition);

        // Obtain the position of the hit GameObject.
        delta = eventData.pointerPressRaycast.worldPosition;
        delta = delta - transform.position;
    }

    public void OnDrag(PointerEventData eventData)
    {
        newPosition = eventData.pointerCurrentRaycast.worldPosition - delta;

        if (eventData.pointerCurrentRaycast.worldPosition.x == 0.0f ||
            eventData.pointerCurrentRaycast.worldPosition.y == 0.0f)
        {
            newPosition = eventData.delta;

            transform.Translate(newPosition * Time.deltaTime);
            return;
        }

        transform.position = newPosition;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        Debug.Log("OnEndDrag");

        transform.position = startPosition;
    }
}