Caching

描述

The Caching class lets you manage cached AssetBundles, downloaded using UnityWebRequestAssetBundle.GetAssetBundle.

Note: The Cache API is not supported in WebGL because AssetBundles are stored in the browser cache for the WebGL platform.

另请参阅：DownloadHandlerAssetBundle。

using System.Collections;
using UnityEngine;
using System.IO;
using System;
using UnityEngine.Networking;
using System.Collections.Generic;

public class Example : MonoBehaviour
{
    IEnumerator DownloadAndCacheAssetBundle(string uri, string manifestBundlePath)
    {
        //Load the manifest
        AssetBundle manifestBundle = AssetBundle.LoadFromFile(manifestBundlePath);
        AssetBundleManifest manifest = manifestBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

        //Create new cache
        string today = DateTime.Today.ToLongDateString();
        Directory.CreateDirectory(today);
        Cache newCache = Caching.AddCache(today);

        //Set current cache for writing to the new cache if the cache is valid
        if (newCache.valid)
            Caching.currentCacheForWriting = newCache;

        //Download the bundle
        Hash128 hash = manifest.GetAssetBundleHash("bundleName");
        UnityWebRequest request = UnityWebRequestAssetBundle.GetAssetBundle(uri, hash, 0);
        yield return request.SendWebRequest();
        AssetBundle bundle = DownloadHandlerAssetBundle.GetContent(request);

        //Get all the cached versions
        List<Hash128> listOfCachedVersions = new List<Hash128>();
        Caching.GetCachedVersions(bundle.name, listOfCachedVersions);

        if (!AssetBundleContainsAssetIWantToLoad(bundle))     //Or any conditions you want to check on your new asset bundle
        {
            //If our criteria wasn't met, we can remove the new cache and revert back to the most recent one
            Caching.currentCacheForWriting = Caching.GetCacheAt(Caching.cacheCount);
            Caching.RemoveCache(newCache);

            for (int i = listOfCachedVersions.Count - 1; i > 0; i--)
            {
                //Load a different bundle from a different cache
                request = UnityWebRequestAssetBundle.GetAssetBundle(uri, listOfCachedVersions[i], 0);
                yield return request.SendWebRequest();
                bundle = DownloadHandlerAssetBundle.GetContent(request);

                //Check and see if the newly loaded bundle from the cache meets your criteria
                if (AssetBundleContainsAssetIWantToLoad(bundle))
                    break;
            }
        }
        else
        {
            //This is if we only want to keep 5 local caches at any time
            if (Caching.cacheCount > 5)
                Caching.RemoveCache(Caching.GetCacheAt(1));     //Removes the oldest user created cache
        }
    }

    bool AssetBundleContainsAssetIWantToLoad(AssetBundle bundle)
    {
        return (bundle.LoadAsset<GameObject>("MyAsset") != null);     //this could be any conditional
    }
}

To store up to five cached versions of the same bundle and use the previous caches if your most recent cache becomes invalid, or the downloaded Asset Bundle has a problem, use the following setup.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using System.IO;

public class Example2 : MonoBehaviour
{
    public static class CacheWithPriority
    {
        public enum ResolutionType
        {
            High,
            Medium,
            Low,
        }
        static readonly Dictionary<ResolutionType, Cache> ResolutionCaches = new Dictionary<ResolutionType, Cache>();

        public static void InitResolutionCaches()
        {
            string highResPath = "HighRes";
            string medResPath = "MedRes";
            string lowResPath = Application.streamingAssetsPath;

            //Create cache paths
            Directory.CreateDirectory(highResPath);
            Directory.CreateDirectory(medResPath);

            //Create the caches and add them to a Dictionary
            ResolutionCaches.Add(ResolutionType.High, Caching.AddCache(highResPath));
            ResolutionCaches.Add(ResolutionType.Medium, Caching.AddCache(medResPath));
            ResolutionCaches.Add(ResolutionType.Low, Caching.AddCache(lowResPath));
        }

        public static void PrioritizeCacheForLoading(ResolutionType resolutionToPrioritize)
        {
            //Move cache to the start of the queue
            Caching.MoveCacheBefore(ResolutionCaches[resolutionToPrioritize], Caching.GetCacheAt(0));
        }

        public static void SetResolutionCacheForWriting(ResolutionType resolutionToWriteTo)
        {
            Caching.currentCacheForWriting = ResolutionCaches[resolutionToWriteTo];
        }
    }

    AssetBundle currentTextureAssetBundle;
    IEnumerator RearrangeCacheOrderExample(string manifestBundlePath)
    {
        CacheWithPriority.InitResolutionCaches();

        //Load the manifest
        AssetBundle manifestBundle = AssetBundle.LoadFromFile(manifestBundlePath);
        AssetBundleManifest manifest = manifestBundle.LoadAsset<AssetBundleManifest>("AssetBundleManifest");

        //We know we want to start loading from the Low Resolution Cache
        CacheWithPriority.PrioritizeCacheForLoading(CacheWithPriority.ResolutionType.Low);

        //Load the low res bundle from StreamingAssets
        UnityWebRequest lowRequest = UnityWebRequestAssetBundle.GetAssetBundle("lowResBundlePath",
            manifest.GetAssetBundleHash("lowResBundle"), 0);
        yield return lowRequest;
        currentTextureAssetBundle = DownloadHandlerAssetBundle.GetContent(lowRequest);

        //In the background we can start downloading our higher resolution bundles
        StartCoroutine(StartDownloadHigherResolutionBundles(manifest));

        //Do work with low res bundle while the higher resolutions download...
    }

    IEnumerator StartDownloadHigherResolutionBundles(AssetBundleManifest manifest)
    {
        CacheWithPriority.SetResolutionCacheForWriting(CacheWithPriority.ResolutionType.Medium);
        UnityWebRequest medRequest = UnityWebRequestAssetBundle.GetAssetBundle("medResBundleUrl", manifest.GetAssetBundleHash("medResBundle"), 0);
        medRequest.SendWebRequest();

        while (!medRequest.isDone)
            yield return null;
        SwitchTextureBundleTo(CacheWithPriority.ResolutionType.Medium, medRequest);

        //Now you'll be using the medium resolution bundle

        CacheWithPriority.SetResolutionCacheForWriting(CacheWithPriority.ResolutionType.High);
        UnityWebRequest highRequest = UnityWebRequestAssetBundle.GetAssetBundle("highResBundleUrl", manifest.GetAssetBundleHash("highResBundle"), 0);
        highRequest.SendWebRequest();

        while (!highRequest.isDone)
            yield return null;
        SwitchTextureBundleTo(CacheWithPriority.ResolutionType.High, highRequest);

        //Do work with the high resolution bundle now...
    }

    void SwitchTextureBundleTo(CacheWithPriority.ResolutionType typeToSwitchTo, UnityWebRequest request)
    {
        //For performance, we tell the Caching system what cache we want it to search first
        CacheWithPriority.PrioritizeCacheForLoading(typeToSwitchTo);
        //Unload our current texture bundle
        currentTextureAssetBundle.Unload(true);
        //Load the new one from the passed in UnityWebRequest
        currentTextureAssetBundle = DownloadHandlerAssetBundle.GetContent(request);
    }
}

拥有多个缓存的功能让您能够保留特定资源捆绑包的多个缓存版本。您可以将它们用于备份和回退等操作。

本示例演示如何在启动后下载中分辨率和高分辨率纹理，并将它们缓存到各自的专用缓存中。

静态变量

静态函数