unity UGUI异步加载进度条

异步加载进度条
1.需要在场景中增加一个Button，一个Slider。（点击button即通过进度条跳转到下一场景。

2.进度加载代码（挂在在场景任一物体上）：
using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class LoadScene : MonoBehaviour
{
public Slider sliders;
public GameObject uitips;
private void Awake()
{
uitips.gameObject.SetActive(false);
}

public void LoadGameScene() {
    uitips.gameObject.SetActive(true);
    StartCoroutine(LoadScenes("SLScene"));
    Debug.Log("jiazai+SLScene");
}
public void ReturnStartScene()
{
    uitips.gameObject.SetActive(true);
    StartCoroutine(LoadScenes("SelectScene"));

}
IEnumerator LoadScenes(string sceneName)
{
    int displayProgress = 0;
    int toProgress = 0;
    AsyncOperation asyncOperation = Application.LoadLevelAsync(sceneName);
    //    置为False ,目的是为了防止加载完后unity自动切换场景
    asyncOperation.allowSceneActivation = false;

    while (asyncOperation.progress < 0.9f)
    {
        toProgress = (int)(asyncOperation.progress * 100);
        while (displayProgress < toProgress)
        {  //  每次在原有加载的进度条的基础上加1 , 为了让看上去是连续加载的
            ++displayProgress;
            SetLoadingPercentage(displayProgress);
            yield return new WaitForEndOfFrame();
        }
        yield return new WaitForEndOfFrame();
    }

    toProgress = 100;
    while (displayProgress < toProgress)
    {
        ++displayProgress;
        SetLoadingPercentage(displayProgress);
        yield return new WaitForEndOfFrame();
    }
    asyncOperation.allowSceneActivation = true;
}

void SetLoadingPercentage(int percentage)
{
   sliders.value = (float)percentage / 100;

}

}
3.将进度加载条方法里的LoadGameScene()方法绑定在UI场景里的Button上。
4.运行程序，点击button按钮即可加载。