Firemonkey TListBox changing background color at runtime - firemonkey

Question

I there a way, at runtime, other than using styles, to change the background color of a TListBox? Can I use the OnPaint event?

Answer 1

Because the TListbox doesn't have a property to change the background color, I can only think of the following, which is based on combining two components, of which one (the TListBox) uses a built-in style. Note however, that this is not depending on TStyleBook nor any of the style files supplied with Delphi Firemonkey.
Place a TRectangle as a background for the TListBox. Set its Fill - Color property to a color you like. (I used "Cornsilk" in the example).
Place the TListBox on the rectangle as a child of the rectangle. In the "Object Inspector" locate the StyleLookup property and change its value to transparentlistboxstyle. This makes the listbox transparent and the rectangle and its fill color to shine through.
If you make the TListBox one pixel smaller than the rectangle on each side, you can use the Sides property to provide a thin frame around the listbox. Or you can choose to make them equally sized and not show any frame.
My test result looks like this:
The TRectangle and the TListbox properties from the .fmx file:
object Rectangle1: TRectangle
Anchors = [akLeft, akTop, akBottom]
Fill.Color = claCornsilk
Position.X = 7.000000000000000000
Position.Y = 40.000000000000000000
Size.Width = 361.000000000000000000
Size.Height = 219.000000000000000000
Size.PlatformDefault = False
object ListBox1: TListBox
Anchors = [akLeft, akTop, akRight, akBottom]
Position.X = 1.000000000000000000
Position.Y = 1.000000000000000000
Size.Width = 359.000000000000000000
Size.Height = 217.000000000000000000
Size.PlatformDefault = False
StyleLookup = 'transparentlistboxstyle'
TabOrder = 0
ParentShowHint = False
ShowHint = False
DisableFocusEffect = True
ItemHeight = 48.000000000000000000
DefaultItemStyles.ItemStyle = 'listboxitemrightdetail'
DefaultItemStyles.GroupHeaderStyle = ''
DefaultItemStyles.GroupFooterStyle = ''
Viewport.Width = 359.000000000000000000
Viewport.Height = 217.000000000000000000
end
end
To change the color of ListBox1, you actually change the color of the TRectangle:
procedure TForm5.ColorListBox1ItemClick(const Sender: TCustomListBox;
const Item: TListBoxItem);
begin
Rectangle1.Fill.Color := TColorListBox(Sender).Color;
end;