Transform.SetAsFirstSibling

説明

ローカルの Transform リストで、一番最初の順番になるよう移動します。

using UnityEngine;
using System.Collections;
using UnityEngine.UI; //Required when using UI Elements.
using UnityEngine.EventSystems; // Required when using event data.

public class ExampleClass : MonoBehaviour, IPointerDownHandler
{
	public RectTransform panelRectTransform;

	//Invoked when the mouse pointer goes down on a UI element. 
	public void OnPointerDown (PointerEventData data) 
	{
		// Puts the panel to the back as it is now the first UI element to be drawn.
		panelRectTransform.SetAsFirstSibling ();
	}
}