Delphi Firemonkey Frames - How to get the event OnEnter and OnExit of the usage of a frame

Question

Using Delphi Tokyo and FireMonkey: I have a lot of different frames on a form and would like to set some form-level variables as the focus on the form changes in and out of the different frames. Ex. I have a Insert button on the form and want to enable it if the frame the user is in allows inserts and then again disable it upon leaving the frame's focus. There are OnEnter and OnExit events on the frame, but they never execute. Obviously there are edits etc. on the frames.

Answer 1

type
  TForm1 = class(TForm)
    Label1: TLabel;
    procedure FormFocusChanged(Sender: TObject);
  private
    FFocusedFrame: TFrame;
  public
    { Public declarations }
  end;

...

procedure TForm1.FormFocusChanged(Sender: TObject);
var
  LParent: TFmxObject;
begin
  if Focused <> nil then
  begin
    LParent := Focused.GetObject.Parent;
    while (LParent <> nil) and not (LParent is TFrame) do
      LParent := LParent.Parent;
    if (LParent <> nil) and (FFocusedFrame <> LParent) then
    begin
      FFocusedFrame := TFrame(LParent);
      Label1.Text := FFocusedFrame.Name;
    end;
  end;
end;

end.

No need to hook up OnEnter and OnExit for every control

Answer 2

The frames can not receive focus, and therefore they do not fire OnEnter() or OnExit() events.

After you have placed a frame on the form, you can create two common event handlers for all edit controls (or other input controls on the frame)

procedure TForm14.Frame112EditExit(Sender: TObject);
begin
  Button1.Enabled := False;
end;

procedure TForm14.Frame112EditEnter(Sender: TObject);
begin
  Button1.Enabled := True;
end;

and link the OnEnter() and OnExit() events of all those edit controls to these two event handlers.

I was unsure whether the events are fired in correct order when moving from one edit control to anotherone, but a short test (on Windows) shows that OnExit() of the control we leave is fired before OnEnter() of the control we enter, as expected.