Unity3D_异步加载场景（进度条）

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class AsyncLoadScene : MonoBehaviour
{
    // 进度条
    public Slider loadingSlider;
    // 文字显示加载进度
    public Text loadingText;
    // 进度条的行进速度
    private float SliderLoadSpeed = 1;
    // 场景加载类的对象
    private AsyncOperation operation;
    // 加载进度(由于加载进度不能为 1，所以需要此变量在加载进度大于某一个值时让加载进度变为1)
    private float targetValue;

    void Start ()
    {
        // 初始化进度条
        loadingSlider.value = 0.0f;

        if (SceneManager.GetActiveScene ().name == "NowSence") {
            // 启动协程
            StartCoroutine (AsyncLoading ());
        }
    }

    void Update ()
    {
        // operation.progress 加载进度
        targetValue = operation.progress;

        if (operation.progress >= 0.9f) {
            // operation.progress的值最大为0.9
            targetValue = 1.0f;
        }

        if (targetValue != loadingSlider.value) {
            // 插值运算（进度条向当前加载进度趋近）
            loadingSlider.value = Mathf.Lerp (loadingSlider.value, targetValue, Time.deltaTime * SliderLoadSpeed);
            // 避免插值运算一直进行
            if (Mathf.Abs (loadingSlider.value - targetValue) < 0.01f) {
                loadingSlider.value = targetValue;
            }
        }
        // 显示加载百分比
        loadingText.text = ((int)(loadingSlider.value * 100)).ToString () + "%";

        // 当进度条完成 100% 时，加载场景
        if ((int)(loadingSlider.value * 100) == 100) {
            //允许异步加载完毕后自动切换场景
            operation.allowSceneActivation = true;
        }
    }

    // 加载场景的协程
    IEnumerator AsyncLoading ()
    {
        // 异步加载场景
        operation = SceneManager.LoadSceneAsync ("LoadSence");
        // 阻止当加载完成自动切换
        operation.allowSceneActivation = false;

        yield return operation;
    }

}