Unity3d asynchronous loading of scenes and progress bar loading

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AsyncOperation

describe

Asynchronous operation synergist .

You can yield Until the asynchronous operation continues , Or manually check that it is complete (isDone) Still in progress (progress).

See also ：SceneManager.LoadSceneAsync、AssetBundle.LoadAssetAsync、Resources.LoadAsync.

Variable

Variable name	effect
allowSceneActivation	Allows the scene to be activated immediately after it is ready .
isDone	Is the operation complete ？（ read-only ）
priority	Priority Allows you to adjust the order in which asynchronous operation calls are performed .
progress	Get the operation progress .（ read-only ）

Events

event	effect
completed	The event called when the operation is completed . Even if the operation can be completed synchronously , The event handler registered in the frame of the call that created it will also be called at the next frame . If the handler is registered after the operation is completed , And called complete event , The handler will be called synchronously .

Code case ：

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

public class AsyncScene : MonoBehaviour
{
    public Text textValue;
    public Slider sliderImg;
    public GameObject showObj;

    AsyncOperation asyncOperation;

    /// <summary>
    ///  Judge whether the asynchronous scene can be loaded 
    /// </summary>
    private bool isLodaScene;
    private bool isLodaScene1;


    private void Update()
    {
        if (isLodaScene&& isLodaScene1)
        {
            if (Input.anyKeyDown)
            {
                asyncOperation.allowSceneActivation = true;
                isLodaScene = false;
            }
        }
    }

    public void startToLoadScene()
    {
        // Start the coroutines 
        StartCoroutine(AsuncLoad());
    }

    private IEnumerator AsuncLoad()
    {
        yield return null;

        isLodaScene = true;

        // According to load UI
        showObj.SetActive(true);

        // Get the index of the currently active scene +1
         asyncOperation = SceneManager.LoadSceneAsync(SceneManager.GetActiveScene().buildIndex+1);

        // It is not allowed to activate the scene immediately after the scene is ready .
        asyncOperation.allowSceneActivation = false;

        // Is the operation complete ？（ read-only ）
        while (!asyncOperation.isDone && isLodaScene)
        {
            // Such as 3d The scene needs to be loaded , There is nothing in the practice scene here, so we need to simulate licking and delay 
            yield return new WaitForSeconds(1f);

            // Get the operation progress .（ read-only ） assignment Slider On 
            sliderImg.value = asyncOperation.progress;

            // Get the operation progress .（ read-only ） assignment Text On the text 
            textValue.text = asyncOperation.progress * 100 + "%";

            if (asyncOperation.progress >= 0.9f )
            {
                // Such as 3d The scene needs to be loaded , There is nothing in the practice scene here, so we need to simulate licking and delay 
                yield return new WaitForSeconds(1f);

                sliderImg.value = 1;

                textValue.text = " The scene is loaded , Press any key to jump to the scene .";

                isLodaScene = false;
            }
            yield return null;
        }
        if (sliderImg.value == 1)
        {
            isLodaScene = true;
            isLodaScene1 = true;
        }
    }
 
}