public override void OnDetach()
        {
            base.OnDetach();

            mModel.ModelChanged -= mModel_ModelChanged;
            mModel = null;
        }
        //================Fragment lifecycle============//


        public override void OnAttach(Activity activity)
        {
            base.OnAttach(activity);

            mModel = new OverviewImageGalleryModel(activity);
            mModel.ModelChanged += mModel_ModelChanged;
        }