download and load asset from AssetBundle with Synchronous Method (Blocking call)

AssetBundleMgr.cs

//
//  AssetBUndleMgr.cs
//
//  Created by Sinhyub Kim 2016.06.05
//

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

#if UNITY_EDITOR
using UnityEditor;
#endif

public class ALAssetBundleMgr
{
  // AssetBundle URL
	public const string ASSETBUNDLE_URL_CHARGRAPHIC = "http://download.url/for_assetbundle.unity3d";

	// CallBack Lambda
	public delegate void LoadAssetBundleCallback(bool isSuccess, AssetBundle assetBundle);
	public delegate void LoadAssetCallback<AssetObjectType>(bool isSuccess, AssetObjectType asset) where AssetObjectType : Object;

	// Asynchronous Method
	// Download or cache assetbundle
	public static IEnumerator AsyncLoadAssetBundle(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();
		}
	}

	// Blocking Method (Synchronous)
	// Download or cache assetbundle
	public static AssetBundle LoadAssetBundle(string assetBundleURL, int versionNumber)
	{
		AssetBundle assetBundleObject = null;
		IEnumerator loadAssetBundleEnumerator = AsyncLoadAssetBundle(assetBundleURL, versionNumber, (bool isSuccess, AssetBundle assetBundle) => 
		{
			assetBundleObject = assetBundle;
		});
		while (loadAssetBundleEnumerator.MoveNext())
		{
			// Spining for Synchronous Behavior (blocking)
		}
		return assetBundleObject;
	}

	// Asynchronous Method
	// Download or cache assetbundle to load an object from the assetbundle.
	public static IEnumerator AsyncLoad<AssetObjectType>(string assetName, string assetBundleURL, int versionNumber, LoadAssetCallback<AssetObjectType> callback) where AssetObjectType : Object
	{
		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
	}

	// Blocking Method (Synchronous)
	// Download or cache assetbundle to load an object from the assetbundle.
	public static AssetObjectType Load<AssetObjectType>(string assetName, string assetBundleURL, int versionNumber) where AssetObjectType : Object
	{
		AssetObjectType assetObject = null;
		IEnumerator loadEnumerator = AsyncLoad<AssetObjectType> (assetName, assetBundleURL, versionNumber, (bool isSuccess, AssetObjectType asset) =>
		{
			if( isSuccess == false )
			{
				assetObject = null;
			}
			else
			{
				assetObject = asset;
			}
		});
		while (loadEnumerator.MoveNext())
		{
			// Spining for Synchronous(Blocking) Behavior
		}
		return assetObject;
	}
}