[NGUI]基于UIDragDropItem脚本实现简单的控件拖拽

废话不多说，直接上代码：

using UnityEngine;
using System.Collections;

/// <summary>
/// 必须保证在NGUI创建的UIRoot下的子控件使用
/// </summary>
public class NewBehaviourScript : MonoBehaviour
{
	private UIRoot m_Root = null;
	private Collider m_Collider = null;

	void Awake()
	{
		m_Root = NGUITools.FindInParents<UIRoot>(gameObject);
		m_Collider = NGUITools.AddWidgetCollider(gameObject) as Collider;
	}
	#region OnDragStart, OnDrag和OnDragEnd是由UICamera触发的函数事件，不能改变
	void OnDragStart()
	{
		if (!enabled) return;
		// 关闭碰撞是为了在OnDragEnd检测放开时触摸的对象
		if (m_Collider != null) m_Collider.enabled = false;
	}
	void OnDrag(Vector2 delta)
	{
		// 改变位置实现移动
		if (m_Root)
			transform.localPosition += (Vector3)delta * m_Root.pixelSizeAdjustment;
	}
	void OnDragEnd()
	{
		DropRelease(UICamera.hoveredObject);

		if (m_Collider != null) m_Collider.enabled = true;
	}
	#endregion
	// 用于处理拖拽结束事件
	private void DropRelease(GameObject surface)
	{
		if (surface)
			transform.parent = surface.transform;
		transform.localPosition = new Vector3(0f,0f,0f);
	}
}