Unity AssetBundle Examples.

AssetBundleSample.cs

using System;
using UnityEngine;
using System.Collections;

public class AssetBundleSample : MonoBehaviour {

  public GUIText guitext;

  // Use this for initialization
  void Start () {
    // Clear Cache
    Caching.CleanCache();

    string loadUrl = "https://dl.dropboxusercontent.com/u/172835/track";

#if   UNITY_ANDROID && !UNITY_EDITOR
    loadUrl += ".android.unity3d";
#elif UNITY_IPHONE  && !UNITY_EDITOR
    loadUrl += ".iphone.unity3d";
#else
    loadUrl += ".unity3d";
#endif

    StartCoroutine(load(loadUrl, 1));
  }
  
  // Update is called once per frame
  void Update () {
    // progress
    int percent = (int)(www.progress * 100);
    guitext.text = percent.ToString() + "%";
  }

  private WWW www;

  private IEnumerator load(string url, int version) {
    // wait for the caching system to be ready
    while (!Caching.ready)
      yield return null;

    // load AssetBundle file from Cache if it exists with the same version or download and store it in the cache
    www = WWW.LoadFromCacheOrDownload(url, version);
    yield return www;

    Debug.Log("Loaded ");

    if (www.error != null)
      throw new Exception("WWW download had an error: " + www.error);
    
    AssetBundle assetBundle = www.assetBundle;
    Instantiate(assetBundle.mainAsset); // Instantiate(assetBundle.Load("AssetName"));
    
    // Unload the AssetBundles compressed contents to conserve memory
    assetBundle.Unload(false);
  }

}

ExportAssetBundles.cs

// Builds an asset bundle from the selected objects in the project view.
// Once compiled go to "Menu" -> "Assets" and select one of the choices
// to build the Asset Bundle
using UnityEngine;
using UnityEditor;

public class ExportAssetBundles {

  [MenuItem("Assets/Build AssetBundle From Selection - Track dependencies")]
  static void ExportResurce() {
    // Bring up save panel
    string basename = Selection.activeObject ? Selection.activeObject.name : "New Resource";
    string path = EditorUtility.SaveFilePanel("Save Resources", "", basename, "");

    if (path.Length != 0) {
      // Build the resource file from the active selection.
      Object[] selection = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets);

      // for Android
      BuildPipeline.BuildAssetBundle(Selection.activeObject,
                                     selection, path + ".android.unity3d",
                                     BuildAssetBundleOptions.CollectDependencies |
                                     BuildAssetBundleOptions.CompleteAssets,
                                     BuildTarget.Android);

      // for iPhone
      BuildPipeline.BuildAssetBundle(Selection.activeObject,
                                     selection, path + ".iphone.unity3d",
                                     BuildAssetBundleOptions.CollectDependencies |
                                     BuildAssetBundleOptions.CompleteAssets,
                                     BuildTarget.iPhone);

      // for WebPlayer
      BuildPipeline.BuildAssetBundle(Selection.activeObject,
                                     selection, path + ".unity3d",
                                     BuildAssetBundleOptions.CollectDependencies |
                                     BuildAssetBundleOptions.CompleteAssets,
                                     BuildTarget.WebPlayer);

      Selection.objects = selection;
    }
  }

  // [MenuItem("Assets/Build AssetBundle From Selection - Track dependencies")]
  // static void ExportResource() {
  //   // Bring up save panel
  //   string path = EditorUtility.SaveFilePanel("Save Resources", "", "New Resource", "unity3d");
  //   if (path.Length != 0) {
  //     // Build the resource file from the active selection.
  //     Object[] selection = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets);
  //     BuildPipeline.BuildAssetBundle(Selection.activeObject,
  //                                    selection,
  //                                    path,
  //                                    BuildAssetBundleOptions.CollectDependencies |
  //                                    BuildAssetBundleOptions.CompleteAssets);
  //     Selection.objects = selection;
  //   }
  // }
  
  // [MenuItem("Assets/Build AssetBundle From Selection - No dependency tracking")]
  // static void ExportResourceNoTrack() {
  //   // Bring up save panel
  //   string path = EditorUtility.SaveFilePanel("Save Resource", "", "New Resource", "unity3d");
  //   if (path.Length != 0) {
  //     // Build the resource file from the active selection.
  //     BuildPipeline.BuildAssetBundle(Selection.activeObject, Selection.objects, path);
  //   }
  // }

}

I've used your ExportAssetBundle.cs script for create .android.unity3d asset files. It was working fine but today when i tried, i got below error. I don't know whats happened,

Building Asset Bundles requires Unity Advanced for AndroidPlayer
UnityEditor.BuildPipeline:BuildAssetBundle(Object, Object[], String, BuildAssetBundleOptions, BuildTarget)
ExportAssetBundles:ExportResurce() (at Assets/Editor/ExportAssetBundles.cs:21)

What is the procedure to export AssetBundle? And How to call AssetBundleSample.cs