Xamarin RenderFactory.GetRenderer（）不工作

我正在使用Xamarin开发一个跨平台控件。我的目标是有一个可选项目的列表。我有一些可以正常工作的iOS代码：

    private UIView CreateViewWithTemplate(UIPickerView pickerView, nint row)
            {
                // create our content presenter
                DYMOContentPresenter presenter = new DYMOContentPresenter();

                // set its data template to the one from our control
                presenter.ItemTemplate = this._pickerControl.ItemTemplate;

                // set the data to the correct item from the list
                presenter.ObjectContent = this._pickerControl.Items.ElementAt((int)row);

                // and use the xamarin forms renderer factory to get a renderer for the item
                IVisualElementRenderer renderer = RendererFactory.GetRenderer(presenter);

                // tell the renderer the size of the view and 
                renderer.SetElementSize(new Size(pickerView.Frame.Width, ROW_HEIGHT));

                // then get the native view and return


 return renderer.NativeView;
        }

然而，我试图在Android中实现这一点的尝试不起作用：

private View CreateViewWithTemplate(int position, View convertView, ViewGroup parent)
{            
    // create content presenter
    DYMOContentPresenter presenter = new DYMOContentPresenter();

    // set its data template to the correct item from the list
    presenter.ItemTemplate = this._pickerControl.ItemTemplate;

    // set data to correct list item
    presenter.ObjectContent = this._pickerControl.Items.ElementAt((int) position);

    // use Xamarin forms renderer factory to get a renderer for the item
    IVisualElementRenderer renderer = RendererFactory.GetRenderer(presenter);

    presenter.Layout(new Xamarin.Forms.Rectangle(0, 0, parent.Width, ROW_HEIGHT));
    renderer.UpdateLayout();
    renderer.Tracker.UpdateLayout();
    renderer.ViewGroup.LayoutParameters = new ViewGroup.LayoutParams(parent.Width, ROW_HEIGHT);
    renderer.ViewGroup.Layout(0, 0, parent.Width, ROW_HEIGHT);
    renderer.ViewGroup.BuildDrawingCache();

    // get native view and return
    return renderer.ViewGroup;
}

我可以看到单个列表视图行，但其中没有文本显示。在注释掉这段代码并用简单的

TextView

替换后，我可以看到文本，因此我怀疑渲染器有问题。我也尝试过此代码的许多变体（指定

LayoutParams

，尝试调整子项大小，等等）。似乎什么都不管用