Unity Asset Bundle Loader

AssetBundleHelper.cs

//
//  AssetBundleHelper.cs
//
//  Created by Sinhyub Kim on 5/22/15.
//

//#define LOAD_ASSETBUNDLE_FROM_LOCAL
//#define SKIP_ASSETDOWNLOAD_ON_EDITOR
using UnityEngine;
using System.Collections;
using UnityEngine.UI;

#if UNITY_EDITOR
using UnityEditor;
#endif

public class AssetBundleHelper
{
	// Download or cache assetbundle
	public delegate void LoadAssetBundleCallback(bool isSuccess, AssetBundle assetBundle);
	public static IEnumerator LoadAssetBundle(string assetBundleURL, int versionNumber, LoadAssetBundleCallback callback)
	{
		while (!Caching.ready)
			yield return null;
		
		using(WWW www = WWW.LoadFromCacheOrDownload (assetBundleURL, versionNumber))
		{
			yield return www;
			if (www.error != null)
			{
				callback(false, null);
				throw new UnityException("WWW download:" + www.error);
			}
			AssetBundle bundle = www.assetBundle;
			callback(bundle!=null, bundle);
			bundle.Unload(false);
			www.Dispose();
		}
	}
	
	// Download or cache assetbundle to load an object from the assetbundle.
	public delegate void LoadAssetCallback<AssetObjectType>(bool isSuccess, AssetObjectType asset) where AssetObjectType : Object;
	public static IEnumerator LoadAsset<AssetObjectType>(string assetName, string assetBundleURL, int versionNumber, LoadAssetCallback<AssetObjectType> callback) where AssetObjectType : Object
	{
		// #if (UNITY_EDITOR&&SKIP_ASSETDOWNLOAD_ON_EDITOR)
		// // Different format of AssetName is required between Resources.Load and assetbundle.LoadAsset.
		// // So belows might not work 
		// AssetObjectType assetObject = Resources.Load<AssetObjectType>(assetName);
		// callback(assetObject!=null, assetObject);
		// yield return null;
		// #else
		while (!Caching.ready)
			yield return null;
		
		using(WWW www = WWW.LoadFromCacheOrDownload (assetBundleURL, versionNumber))
		{
			yield return www;
			if (www.error != null)
			{
				callback(false, null);
				throw new UnityException("WWW download:" + www.error);
			}
			AssetBundle bundle = www.assetBundle;
			
			AssetBundleRequest request = bundle.LoadAssetAsync<AssetObjectType>(assetName);
			yield return request;
			
			AssetObjectType assetObject = request.asset as AssetObjectType;
			callback(assetObject!=null, assetObject);
			bundle.Unload(false);
			
			www.Dispose();
		}
		//#endif
	}
}


// an example to load a sprite from an asset bundle
public class ExampleTestObj : MonoBehaviour {

	public Image testImage;

	// 1. AssetBundleTest.unity3d is an asset bundle including AssetBundleTestImage (.png)
	void LoadFromLocal()
	{
		string assetBundleLocalPath = "file://"+System.IO.Path.Combine ( Application.dataPath, "Resources/AssetBundleTest/AssetBundleTest.unity3d" );
		StartCoroutine( AssetBundleHelper.LoadAsset<Sprite>("AssetBundleTestImage", assetBundleLocalPath, 1, (bool isSuccess, Sprite spriteObject) =>
		{
			if (isSuccess == false)
			{
				throw new UnityException ("Failed to load test sprite");
				return;
			}
			
			this.testImage.sprite = spriteObject;
		}));
	}
	void LoadFromWeb()
	{
		string assetBundleURL = "http://www.googledrive.com/host/0B6Dbmbd_-1doSGZKemlBT2taTk0/AssetBundleTest.unity3d";
		StartCoroutine( AssetBundleHelper.LoadAsset<Sprite>("AssetBundleTestImage", assetBundleURL, 1, (bool isSuccess, Sprite spriteObject) =>
		{
			if (isSuccess == false)
			{
				throw new UnityException ("Failed to load test sprite");
				return;
			}
			
			this.testImage.sprite = spriteObject;
		}));
	}
	void Awake()
	{
		#if !LOAD_ASSETBUNDLE_FROM_LOCAL
			LoadFromWeb();
		#else
			LoadFromLocal();
		#endif
	}
}