Firemonkey ListView scrollbar visibility - delphi

Question

In the Firemonkey's TListview the visibility of the scroll bar depends whether the system has a touch screen. How can I override this behavior and show vertical scrolling always when there is not enough room on the list view to display all list items?
I saw within TListViewBase.Create that the scroll visibility depends again on the function result of HasTouchTracking and this depends if TScrollingBehaviour.TouchTracking is set in SystemInformationService.GetScrollingBehaviour.
Does anyone have a glue how I can override this behavior?

Answer 1

A while ago I "threw together" (in a hurry) this unit to override GetScrollingBehaviour for Windows. You could do something similar for whichever platform(s) you want to override it for. In the Create method, I remove the installed service, but keep a reference to it for the parts that are not overridden, then replace it with my own.
unit DW.ScrollingBehaviourPatch.Win;
// This unit is used for testing of "inertial" scrolling of listviews etc on devices that do not have touch capability
interface
implementation
uses
FMX.Platform;
type
TPlatform = class(TInterfacedObject, IFMXSystemInformationService)
private
class var FPlatform: TPlatform;
private
FSysInfoService: IFMXSystemInformationService;
public
{ IFMXSystemInformationService }
function GetScrollingBehaviour: TScrollingBehaviours;
function GetMinScrollThumbSize: Single;
function GetCaretWidth: Integer;
function GetMenuShowDelay: Integer;
public
constructor Create;
destructor Destroy; override;
end;
{ TPlatform }
constructor TPlatform.Create;
begin
inherited;
if TPlatformServices.Current.SupportsPlatformService(IFMXSystemInformationService, FSysInfoService) then
TPlatformServices.Current.RemovePlatformService(IFMXSystemInformationService);
TPlatformServices.Current.AddPlatformService(IFMXSystemInformationService, Self);
FPlatform := Self;
end;
destructor TPlatform.Destroy;
begin
//
inherited;
end;
function TPlatform.GetCaretWidth: Integer;
begin
Result := FSysInfoService.GetCaretWidth;
end;
function TPlatform.GetMenuShowDelay: Integer;
begin
Result := FSysInfoService.GetMenuShowDelay;
end;
function TPlatform.GetMinScrollThumbSize: Single;
begin
Result := FSysInfoService.GetMinScrollThumbSize;
end;
function TPlatform.GetScrollingBehaviour: TScrollingBehaviours;
begin
Result := [TScrollingBehaviour.Animation, TScrollingBehaviour.TouchTracking];
end;
initialization
TPlatform.Create;
end.

Answer 2

For Dave's proposed workaround, the touch tracking needs to be turned off as follows:
function TPlatformListViewWorkaround.GetScrollingBehaviour: TScrollingBehaviours;
begin
result := fSysInfoService.GetScrollingBehaviour - [TScrollingBehaviour.TouchTracking];
end;
With this solution, however, you have to accept that the listview on touchscreen systems can no longer be scrolled with the finger.
That's why I have now opened a change request in the Embarcadero Quality Central and suggested a solution proposal by extending the TListView with a new property SuppressScrollBarOnTouchSystems (RSP-26584).