德爾福設置TExpander高度

Question

我有一個TExpander組件，我在運行時添加了一些TTexts，我面臨的問題是：這個擴展器的高度如何根據TText的數量設置，像AutoSize ？

我正在使用的代碼：

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; 

這裏就是我得到

謝謝。

Answer 1

實際上，當您將Eventstext.Parent設置爲expander1時，此對象將添加到受保護字段FContent。所以，如果你想計算真實的大小作爲所有內部控制的總和，你必須得到這個領域。

可以 「覆蓋」 TExpander類是這樣的：

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;