Load and activate dataset dynamically (wuforia and unity)

I want to create a system that I can use to dynamically download various objects from my site without using the "Cloud" system. I also want to save the dataset in .xml and .dat formats that I want to activate from my saving device.

There are many methods and pages that can be done with vuforia and unity, but unfortunately when I test it I get an error for all of them. It seems that I made a mistake in my code or the vuforia class has changed.

For example, check out this link: https://developer.vuforia.com/library/articles/Solution/Unity-Load-DataSet-from-SD-Card I got an error: Using Vuforia;

I put the .xml and .dat files in "Application.persistentDataPath +" / "+" Building1.xml "I used this Script" DataSetLoadBehavior "which bound the" AR camera "and put my code in it. I got the error:

NullReferenceException: Object reference not set to DataSetLoadBehaviour.OnInitialized () object instance (in Assets / Qualcomm Augmented Reality / Scripts / DataSetLoadBehaviour.cs: 49) DataSetLoadBehaviour.Start () (in Assets / Qualcomm. Augmented Reality / DataSetL script cs: 80)

My code:

unit 4.2 pro and vuforia 2.8.9 or 3.0.9

/*==============================================================================
Copyright (c) 2010-2014 Qualcomm Connected Experiences, Inc.
All Rights Reserved.
Confidential and Proprietary - Qualcomm Connected Experiences, Inc.
==============================================================================*/

using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// This behaviour allows to automatically load and activate one or more DataSet on startup
/// </summary>
public class DataSetLoadBehaviour : DataSetLoadAbstractBehaviour
{
       [HideInInspector, SerializeField]
       public List<string> mDataSetsToActivate2 = new List<string>();
      [SerializeField, HideInInspector]
    public List<string> mDataSetsToLoad2 = new List<string>();

    protected DataSetLoadBehaviour()
    {
    }
    private void OnDestroy()
    {
        QCARAbstractBehaviour behaviour = (QCARAbstractBehaviour) UnityEngine.Object.FindObjectOfType(typeof(QCARAbstractBehaviour));
        if (behaviour != null)
        {

        }
    }

    public void OnInitialized()
    {

        if (QCARRuntimeUtilities.IsQCAREnabled())
        {
            foreach (string str in this.mDataSetsToLoad2)
            {

                if (!DataSet.Exists(str, QCARUnity.StorageType.STORAGE_ABSOLUTE))

                {
                    Debug.LogError("Data set " + str + " does not exist.");
                }
                else
                {

                    ImageTracker tracker = TrackerManager.Instance.GetTracker<ImageTracker>();
                    DataSet dataSet = tracker.CreateDataSet();
                    if (!dataSet.Load(str))
                    {
                        Debug.LogError("Failed to load data set " + str + ".");
                    }
                    else if (this.mDataSetsToActivate2.Contains(str))
                    {
                        tracker.ActivateDataSet(dataSet);
                    }
                }
            }
        }
    }

    public void OnTrackablesUpdated()
    {
    }

    private void Start()
    {

        QCARAbstractBehaviour behaviour = (QCARAbstractBehaviour) UnityEngine.Object.FindObjectOfType(typeof(QCARAbstractBehaviour));
        if (behaviour != null)
        {


            mDataSetsToLoad2.Add(Application.persistentDataPath + "/" + "Building1.xml");




            OnInitialized();
        }
    }
    public override void AddOSSpecificExternalDatasetSearchDirs()
    {
#if UNITY_ANDROID
        if (Application.platform == RuntimePlatform.Android)
        {
            // Get the external storage directory
            AndroidJavaClass jclassEnvironment = new AndroidJavaClass("android.os.Environment");
            AndroidJavaObject jobjFile = jclassEnvironment.CallStatic<AndroidJavaObject>("getExternalStorageDirectory");
            string externalStorageDirectory = jobjFile.Call<string>("getAbsolutePath");

            // Get the package name
            AndroidJavaObject jobjActivity = new AndroidJavaClass("com.unity3d.player.UnityPlayer").GetStatic<AndroidJavaObject>("currentActivity");
            string packageName = jobjActivity.Call<string>("getPackageName");

            // Add some best practice search directories
            //
            // Assumes just Vufroria datasets extracted to the files directory
            AddExternalDatasetSearchDir(externalStorageDirectory + "/Android/data/" + packageName + "/files/");
            // Assume entire StreamingAssets dir is extracted here and our datasets are in the "QCAR" directory
            AddExternalDatasetSearchDir(externalStorageDirectory + "/Android/data/" + packageName + "/files/QCAR/");
        }
#endif //UNITY_ANDROID
    }

    void Update()
    {

    }

}