[HINT] Can you create a TALComboBox ?

[maurobotta]

Hi @Zeus64

There is no decent alternative to the original Delphi FMX TComboBox component.

In my iOS/Android mobile app, I’m facing graphical inconsistencies: the default TComboBox components don’t integrate well with dark themes, especially on iOS, and they cause visual issues.

Below is an example of widely used source code (cbDestinazione: TComboBox). It would be important to maintain good compatibility with existing Pascal code.

( @ETSPMeder Any hint ? )

Best Regards
Mauro Botta

function Example_Load_TCombobox(tblOrigine: TFDMemTable; cbDestinazione: TComboBox): string;
var
myListItem: TListBoxItem;
begin
Result := '';

cbDestinazione.Items.BeginUpdate;

cbDestinazione.Items.Clear;

myListItem := TListBoxItem.Create(cbDestinazione);
..
if cbDestinazione.DropDownKind <> TDropDownKind.Custom then
cbDestinazione.DropDownKind := TDropDownKind.Custom;
..
if cbDestinazione.HelpContext <> 0 then
Tag := cbDestinazione.HelpContext;
..
myListItem.Text := tblOrigine.FieldByName(sCampoDesc).AsString;
cbDestinazione.AddObject(myListItem);

..

cbDestinazione.Items.EndUpdate;

end;

[Zeus64]

Hi @maurobotta,

You’re running into a well-known limitation of the standard Delphi FMX TComboBox, especially on mobile platforms.

The issue is not only visual (dark mode, iOS inconsistencies), but also conceptual: the desktop-style combobox is not really a good fit for modern mobile UX. On iOS and Android, users expect:

• full-screen pickers
• bottom sheets
• searchable lists

—not small dropdowns embedded in the UI.

About FMX TComboBox

TComboBox in FMX tries to behave consistently across platforms, but:

• it does not use fully native controls
• styling (especially dark mode) is fragile
• rendering differs between iOS and Android
• customization is limited and sometimes breaks visually

So what you’re seeing is unfortunately expected.

Recommended approach in Alcinoe

In Alcinoe, the usual approach is not to replicate TComboBox, but to use mobile-native UX patterns.

1. Use a picker / dialog instead of a combobox

The most robust pattern is:

a TALButton or TALEdit that opens a selection dialog (TALbottomSheet or TALDialog)

This gives:

• perfect control over theming (including dark mode)
• consistent behavior on iOS and Android
• better UX for long lists

2. Use a searchable list for large datasets

For cases like your example (data coming from TFDMemTable), a better pattern is:

• open a modal view (or bottom sheet)
• display items in a custom layout
• optionally add a search field

This replaces:

cbDestinazione.AddObject(myListItem);

with a more scalable and mobile-friendly UI.

3. Keep compatibility with existing code

If you want to keep your existing logic (like Example_Load_TCombobox), a good compromise is to create a wrapper component, for example:

TALComboBox = class(TALButton)
private
  FItems: TArray<string>;
public
  procedure SetItems(...); // reuse your existing loading logic
  procedure ShowPicker;    // opens dialog
end;

So you:

• keep your data-loading code
• replace only the UI layer
• avoid FMX TComboBox completely

Why Alcinoe doesn’t provide a direct replacement

Alcinoe focuses on performance and mobile-first UI, so:

it avoids components that don’t map well to mobile UX
it gives building blocks instead (layouts, lists, dialogs)

A “perfect” combobox would still suffer from:

platform inconsistencies
poor UX on mobile

[pmeder]

@maurobotta
Removing the FMX Combobox Objects in my Project with the TALDialog and TALButton/Checkbox/Toggle is my Favorite Approach on that. For short lists it is a fast and stable Methode. For Bigger lists Like @Zeus64 Said I have Forms that load dynamicaly with the TALDynamicListBox to Stay responsive and have a Searchbar one top of the Form. (Sorry, my private GitHub User Account ist logged in 🙈)