如何为 Delphi FMX Android TFramedVertScrollBox 配置右垂直滚动？

Question

I have Delphi FMX Android TFramedVerScrollBox with:

Margins.Right:=20;
ShowScrollbars:=True;
TouchTargeExpansion.Right:=80;
Width:=800;

which has a set of TLayout components as a set of children with individual settings for each TLayout:

Align:=Top;
Anchors:=[akLeft, akTop, akRight]
Size.Wdith:=800; //But I guess this is irrelevant, as Size should be determined automatically for children with Align:=Top

My question is - how can I set properties in a way, that:

• TLayout children components give some space in their correct size for scrollbars to become visible? If TLayout.Padding.Right:=0, then TLayout children sit solidly in the place where the vertical scrollbar should be. If TLayout.Padding.Right:=50, then the entire children are moved to the left side - this is really strange. If width is computed automatically for the Align:=Tope children, then this Width should take into account the Padding of the children automatically and accordingly become smaller, less comprehensive.
• Even I move the children to the left side and the scrollbar becomes visible - it is very, very narrow, just some 5-10 pixels. How can I increase the width of the scrollbar of TFramedVerScrollBox?

Answer 1

First: "Padding" adds space to the inner side of the control (between the control borders and its children), while "Margins" adds space to the outer side of the control (to the borders of its Parent or between the control borders and another control within the same Parent).

So when you need to set distance between a TLayout and its "Parent" border (Right border of the TFramedVertScrollBox) then you must go either for Padding in the TFramedVertScrollBox or for Margins in its children controls.

But it is not necessary to set space for scrollbars. Because when a scrollbox (in Delphi apps like in anywhere else) is resized and its children are not completely visible, the scrollbox client area is resized automatically for letting space for showing scrollbars. And even if you set "Margins" for children controls, the scrollbox client area is resized and the children margins are moved. So you will get more margins that will ruin your UI design.

That size adaptation is common on Windows where the scrollbars are always completely shown with their classical aspect. While on Android, scrollbars are not explicitly shown, you may only see their "thumbs" when you try to drag on the side having the scrollbar.

Second: The width of the scrollbar in TFramedVertScrollBox, like all layout controls, is defined by the style. You have to customize the style or create your own style where you can set the size and even the position of the scrollbar.