delphi set the TExpander height - delphi

Question

i've a TExpander component and i add some TTexts to it at runtime , the issue i'm facing is : how can this Expander's height be set based on the Number of the TTexts , something like AutoSize ?
the code i'm using :
procedure TForm1.Button5Click(Sender: TObject);
var
_DailyEvent:TDailyEvents;
Eventstext:TText;
_Y:Integer;
begin
_Y:=10;
For _DailyEvent in DailyEventsList do
begin
Eventstext:=TText.Create(Self);
Eventstext.Position.Y := _Y;
Eventstext.Align:=TAlignLayout.Top;
Eventstext.Height:=25;
Eventstext.TagString:=_DailyEvent.EventID;
Eventstext.Text:=_DailyEvent.EventName;
Eventstext.Parent:=Expander1;
inc(_Y, 15);
end;
Expander1.Height:=?
end;
here's what i get
thank you .

Answer 1

Actually, when you set Eventstext.Parent to expander1, this object added to protected field FContent. So, if you want calculate real size as sum of all inner controls, you must get this field.
You can "override" TExpander class like this:
type
// declare new TExpander class before form declaration
// thanks to this declaration we have access to protected fields
TExpander = class(FMX.StdCtrls.TExpander)
protected
procedure DoExpandedChanged; override;
public
function GetRealRect: TRectF;
end;
TForm2 = class(TForm)
expndr1: TExpander; // this is our new class, not "standart" TExpander
btnAdd10: TButton;
btnDelLast: TButton;
procedure btnAdd10Click(Sender: TObject);
procedure btnDelLastClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form2: TForm2;
implementation
{$R *.fmx}
procedure TForm2.btnAdd10Click(Sender: TObject);
var
Eventstext: TText;
i: integer;
_Y: integer;
begin
_Y := 10;
For i := 1 to 10 do
begin
Eventstext := TText.Create(Self);
Eventstext.Position.Y := _Y;
Eventstext.Align := TAlignLayout.Top;
Eventstext.Height := 25;
Eventstext.Text := i.ToString;
Eventstext.Parent := expndr1;
inc(_Y, 25);
end;
// of course, this is not real Autosize,
// you can override AddObject in TExpander and change size in it,
// but you can`t get access to RemoveObject in FContent...
// thus, "AutoSize" will be limited only to adding items.
// I think the current way is much better than override AddObject...
expndr1.SetBoundsRect(expndr1.GetRealRect);
// or expndr1.height:=expndr1.GetRealRect.Height;
end;
procedure TForm2.btnDelLastClick(Sender: TObject);
begin
if expndr1.FContent.ChildrenCount <> 0 then
begin
expndr1.FContent.Children[expndr1.FContent.ChildrenCount - 1].Release;
expndr1.SetBoundsRect(expndr1.GetRealRect);
end;
end;
{ TExpander }
procedure TExpander.DoExpandedChanged;
begin
inherited;
SetBoundsRect(GetRealRect);
end;
function TExpander.GetRealRect: TRectF;
var
i: integer;
LControl: TControl;
begin
// above FContent are Button, Text and Checkbox
Result.TopLeft := AbsoluteRect.TopLeft;
Result.BottomRight := FContent.AbsoluteRect.TopLeft;
if FIsExpanded then
for i := 0 to FContent.ChildrenCount - 1 do
if FContent.Children[i] is TControl then
begin
LControl := TControl(FContent.Children[i]);
if LControl.Visible then
UnionRectF(Result, Result, LControl.ChildrenRect);
end;
if Result.Width = 0 then // if there are no controls in FContent.
Result.Width := Width;
end;