如何让UI屏幕自适应呢

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

namespace Game.Utility
{
    public class CavansController : MonoBehaviour
    {
        private CanvasScaler m_Scaler;
        // Use this for initialization
        void Awake()
        {
            m_Scaler = GetComponent<CanvasScaler>();
            var sizeDesign = m_Scaler.referenceResolution;
            var rateDesign = sizeDesign.x / sizeDesign.y;
            var rateScreen = Screen.width / Screen.height;
            if (rateDesign > rateScreen) {
                m_Scaler.matchWidthOrHeight = 0.0f;
            } else {
                m_Scaler.matchWidthOrHeight = 1.0f;
            }
        }

    }
}