public override void UnBind()
    {
        this.View.mCloseButton.TappedOn -= OnTappedOnCloseButton;
        this.View.mButtonTwo.TappedOn   -= OnTappedOnButtonTwo;
        this.View.mButtonFour.TappedOn  -= OnTappedOnButtonFour;
        this.View.mButtonThree.TappedOn -= OnTappedOnButtonThree;
        this.View.mButtonOne.TappedOn   -= OnTappedOnButtonOne;
        this.View.mAboutButton.TappedOn -= OnTappedOnAboutButton;

        // unregister Vuforia started callback
        VuforiaAbstractBehaviour vuforiaBehaviour = (VuforiaAbstractBehaviour)FindObjectOfType(typeof(VuforiaAbstractBehaviour));

        if (vuforiaBehaviour)
        {
            vuforiaBehaviour.UnregisterVuforiaStartedCallback(EnableContinuousAutoFocus);
            vuforiaBehaviour.UnregisterOnPauseCallback(OnPause);
        }

        mVBPositionDict.Clear();
        mVBScaleDict.Clear();
        this.View.UnLoadView();
        mView = null;
    }
    public override  void UnBind()
    { 
        this.View.mCloseButton.TappedOn             -= OnTappedOnCloseButton;
        this.View.mVirtualGreenButton.TappedOn      -= OnTappedOnGreenButton;
        this.View.mVirtualYellowButton.TappedOn     -= OnTappedOnYellowButton;
        this.View.mVirtualRedButton.TappedOn        -= OnTappedOnRedButton;
        this.View.mVirtualBlueButton.TappedOn       -= OnTappedOnBlueButton;
        this.View.mAboutButton.TappedOn             -= OnTappedOnAboutButton;

        // unregister Vuforia started callback
        VuforiaAbstractBehaviour vuforiaBehaviour = (VuforiaAbstractBehaviour)FindObjectOfType(typeof(VuforiaAbstractBehaviour));
        if (vuforiaBehaviour)
        {
            vuforiaBehaviour.UnregisterVuforiaStartedCallback(EnableContinuousAutoFocus);
            vuforiaBehaviour.UnregisterOnPauseCallback(OnPause);
        }

        mVBPositionDict.Clear();
        mVBScaleDict.Clear();
        this.View.UnLoadView();
        mView = null;
    }