My first FMX Control (Trying to create a FMX TRadioGroup) – class not found error

  

Using Delphi XE6

I am trying to create an FMX RadioGroup control using a TGroupBox and TRadioButton. I can see both my TTestRadioGroup and TTestGroupButton controls in my IDE control pallette. I can drop a TTestRadioGroup on my form and set the items property and it will create the Radio buttons. However, when I run the application and call the form with the TTestRadioGroup control with its radio buttons, on it, I get a “cant find TTestGroupButton” message.

What have I done wrong?

My first test seems to work ok, as long as I am in design. When

unit TestComponent;

interface

uses {$IFDEF MSWINDOWS}Windows, {$ENDIF}
System.Classes, FMX.Edit, System.UITypes, System.Character, FMX.DateTimeCtrls,
System.SysUtils, FMX.Types, System.DateUtils, System.SysConst, FMX.Controls,
FMX.Pickers, FMX.Platform, FMX.Text, math, FMX.Consts, FMX.Forms, FMX.StdCtrls;

type

TTestRadioGroup = class;

TTestGroupButton = class(TRadioButton)
private
protected
public
constructor InternalCreate(RadioGroup: TTestRadioGroup);
destructor Destroy; override;
end;

TTestRadioGroup = class(TGroupBox)
private
FReading: Boolean;
FButtons: TList;
FItems: TStrings;
FItemIndex: Integer;
FColumns: Integer;
FUpdating: Boolean;
FButtonMargins: Integer;
fButtonSpacing: Integer;
function GetButtons(Index: Integer): TRadioButton;
procedure SetButtonMargins(Value: Integer);
procedure SetButtonSpacing(Value: Integer);
procedure SetColumns(Value: Integer);
procedure SetItemIndex(Value: Integer);
procedure SetItems(Value: TStrings);
procedure ItemsChange(Sender: TObject);
procedure SetButtonCount(Value: Integer);
procedure ButtonClick(Sender: TObject);
procedure UpdateButtons; //updates buttons list from Items list
procedure ArrangeButtons; //rearranges buttons on Groupbox based on new properties
protected
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property Buttons[Index: Integer]: TRadioButton read GetButtons;
published
property ItemIndex: Integer read FItemIndex write SetItemIndex default -1;
property Items: TStrings read FItems write SetItems;
property Columns: Integer read FColumns write SetColumns default 1;
property ButtonMargins: Integer read fButtonMargins write SetButtonMargins default 0;
property ButtonSpacing: Integer read fButtonSpacing write SetButtonSpacing default 0;
end;

procedure Register;

implementation

procedure Register;
begin
RegisterComponents(‘Test’, [TTestRadioGroup, TTestGroupButton]);
end;

{ TTestGroupButton }

constructor TTestGroupButton.InternalCreate(RadioGroup: TTestRadioGroup);
begin
inherited Create(RadioGroup);
RadioGroup.FButtons.Add(Self);
Visible := False;
Enabled := RadioGroup.Enabled;
OnClick := RadioGroup.ButtonClick;
Parent := RadioGroup;
end;

destructor TTestGroupButton.Destroy;
begin
TTestRadioGroup(Owner).FButtons.Remove(Self);
inherited Destroy;
end;

{ TTestRadioGroup }

constructor TTestRadioGroup.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FButtons := TList.Create;
FItems := TStringList.Create;
TStringList(FItems).OnChange := ItemsChange;
FItemIndex := -1;
FColumns := 1;
end;

destructor TTestRadioGroup.Destroy;
begin
SetButtonCount(0);
TStringList(FItems).OnChange := nil;
FItems.Free;
FButtons.Free;
inherited Destroy;
end;

procedure TTestRadioGroup.ArrangeButtons;
var
I,Y: Integer ;
begin
if (FButtons.Count <> 0) and not FReading then
begin
try
Y:= 10;
for I := 0 to FButtons.Count – 1 do
with TTestGroupButton(FButtons[I]) do
begin
Position.X:= 10;
Position.Y:= Y;
Y:= Y + 10;
Visible := True;
end;
finally
end;
end;
end;

procedure TTestRadioGroup.UpdateButtons;
var
I: Integer;
begin
SetButtonCount(FItems.Count);
for I := 0 to FButtons.Count – 1 do
TRadioButton(FButtons[I]).Text := FItems[I];
if FItemIndex >= 0 then
begin
FUpdating := True;
TRadioButton(FButtons[FItemIndex]).isChecked := True;
FUpdating := False;
end;
ArrangeButtons;
Repaint;
end;

procedure TTestRadioGroup.ButtonClick(Sender: TObject);
begin
if not FUpdating then
begin
FItemIndex := FButtons.IndexOf(Sender);
Change;
Click;
end;
end;

procedure TTestRadioGroup.ItemsChange(Sender: TObject);
begin
if not FReading then
begin
if FItemIndex >= FItems.Count then
FItemIndex := FItems.Count – 1;
UpdateButtons;
end;
end;

procedure TTestRadioGroup.SetColumns(Value: Integer);
begin
if Value < 1 then Value := 1;
if Value > 16 then Value := 16;
if FColumns <> Value then
begin
FColumns := Value;
ArrangeButtons;
Repaint;
end;
end;

procedure TTestRadioGroup.SetItemIndex(Value: Integer);
begin
if FReading then FItemIndex := Value else
begin
if Value < -1 then Value := -1;
if Value >= FButtons.Count then Value := FButtons.Count – 1;
if FItemIndex <> Value then
begin
if FItemIndex >= 0 then
TRadioButton(FButtons[FItemIndex]).isChecked := False;
FItemIndex := Value;
if FItemIndex >= 0 then
TRadioButton(FButtons[FItemIndex]).isChecked := True;
end;
end;
end;

procedure TTestRadioGroup.SetItems(Value: TStrings);
begin
FItems.Assign(Value);
end;

procedure TTestRadioGroup.SetButtonCount(Value: Integer);
begin
while FButtons.Count < Value do
TTestGroupButton.InternalCreate(Self);
while FButtons.Count > Value do
TTestGroupButton(FButtons.Last).Free;
end;

procedure TTestRadioGroup.SetButtonMargins(Value: Integer);
begin
if fButtonMargins <> Value then
fButtonMargins:= Value;
ArrangeButtons;
end;

procedure TTestRadioGroup.SetButtonSpacing(Value: Integer);
begin
if fButtonSpacing <> Value then
fButtonSpacing:= Value;
ArrangeButtons;
end;

function TTestRadioGroup.GetButtons(Index: Integer): TRadioButton;
begin
Result := TRadioButton(FButtons[Index]);
end;

end.

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