Dynamisches Menü mit Panels und Collection

[Cyberaxx]

Hallo,

Habe ein Problem mit der Erstellung eines Menüs bestehend aus der Verwaltungsklasse, der Collection und den CollectionItems.
Diese bestehen eigentlich nur aus einem TJvPanel.

Von außen kann das aktive CollectionItem gesetzt und geholt werden. Zudem reagieren die Panels auch auf den Klick.
Wenn das erste Item aktiv ist, ich drauf klicke und das Menü klappt es ohne Probleme. Ist aber ein anderes ITem aktiv so bekomme ich eine AV wenn er in die OnClick Methode zurück springt. Das Panel aber nicht mehr existiert, das das Menü ja bereits gelöscht ist.
Das Panel nutze ich damit ich den Rahmen farblich unterlegen kann für das aktive Item.

Delphi-Quellcode:

unit menu_class;

interface

uses
  Classes, Defines, Windows, SysUtils, Controls, Graphics, JvPanel;

type
  TButtonStyle = (etButton, etSeperator, etText);

type
  TMenuEntry = class(TCollectionItem)
  private
    FPanel: TJvPanel;
    FButtonStyle: TButtonStyle;
  public
    destructor Destroy(); override;
    property Button: TJvPanel read FPanel write FPanel;
    property ButtonStyle: TButtonStyle read FButtonStyle write FButtonStyle;
  end;

type
  TMenuEntries = class(TCollection)
  private
    function GetEntry(Index: Integer): TMenuEntry;
  public
    constructor Create;
    destructor Destroy; override;
    function Add(AOwner: TWinControl): TMenuEntry;
    procedure Del(Index: Integer);
    property MenuEntry[Index: Integer]: TMenuEntry read GetEntry;
  end;

type
  TMenuManager = class(TObject)
  private
    FOwner: TWinControl;
    FXPos: Integer;
    FYPos: Integer;
    FTempYPos: Integer;
    FMenuEntries: TMenuEntries;
    FActiveButton: Integer;
    FItemClick: TNotifyEvent;
    function GetAcctiveButton: Integer;
    procedure SetActiveButton(const Value: Integer);
    procedure OnClick(Sender: TObject);
  public
    constructor Create(AOwner: TWinControl; XPos, YPos: Integer);
    destructor Destroy; override;
    procedure AddButton(Caption: String; ButtonStyle: TButtonStyle = etButton);
    procedure RemoveButton(Index: Integer);
    procedure ClearButtons;
    function Count: Integer;
    property ButtonActive: Integer read GetAcctiveButton write SetActiveButton;
    property OnItemClick: TNotifyEvent read FItemClick write FItemClick;
  end;

implementation

{ TMenuManager }

procedure TMenuManager.AddButton(Caption: String;
  ButtonStyle: TButtonStyle);
  var
    AMenuEntry: TMenuEntry;
begin
  Self.FTempYPos := Self.FMenuEntries.Count * 40 + Self.FYPos;

  AMenuEntry := Self.FMenuEntries.Add(Self.FOwner);
  AMenuEntry.FPanel.DoubleBuffered := True;
  AMenuEntry.FPanel.Left := Self.FXPos;
  AMenuEntry.FPanel.Top := Self.FTempYPos;
  AMenuEntry.FPanel.Height := 33;
  AMenuEntry.FPanel.Width := 233;
  AMenuEntry.FPanel.Transparent := True;
  AMenuEntry.FPanel.BevelInner := bvNone;
  AMenuEntry.FPanel.BevelOuter := bvNone;
  AMenuEntry.FPanel.Color := clGray;
  AMenuEntry.FPanel.Alignment := taLeftJustify;
  AMenuEntry.FPanel.Caption := Caption;
  AMenuEntry.FPanel.Font.Color := clBlack;
  AMenuEntry.FPanel.Font.Size := 24;
  AMenuEntry.FPanel.Font.Style := [fsBold];

  if ButtonStyle = etSeperator then
    AMenuEntry.FPanel.BorderWidth := 0
      else AMenuEntry.FPanel.BorderWidth := 1;

  AMenuEntry.FPanel.Parent := FOwner;
  AMenuEntry.FPanel.OnClick := Self.OnClick;
  AMenuEntry.FPanel.Tag := AMenuEntry.Index;

  AMenuEntry.FButtonStyle := ButtonStyle;
end;

procedure TMenuManager.ClearButtons;
begin
  while Self.FMenuEntries.Count > 0 do begin
    Self.FMenuEntries.Del(Self.FMenuEntries.Count -1);
    end;
end;

function TMenuManager.Count: Integer;
begin
  Result := Self.FMenuEntries.Count;
end;

constructor TMenuManager.Create(AOwner: TWinControl; XPos, YPos: Integer);
begin
  inherited Create;

  Self.FOwner := AOwner;
  Self.FXPos := XPos;
  Self.FYPos := YPos;
  Self.FTempYPos := Self.FYPos;
  Self.FActiveButton := -1;

  Self.FMenuEntries := TMenuEntries.Create;
end;

destructor TMenuManager.Destroy;
begin
  Self.ClearButtons;
  Self.FMenuEntries.Destroy;

  inherited Destroy;
end;

function TMenuManager.GetAcctiveButton: Integer;
begin
  Result := Self.FActiveButton;
end;

procedure TMenuManager.OnClick(Sender: TObject);
begin
  if Assigned(FItemClick) then begin
    if Sender is TJvPanel then begin
      Self.SetActiveButton(TJvPanel(Sender).Tag);
      //Self.FActiveButton := TJvPanel(Sender).Tag;
      OnItemClick(Self);
      // <-- panel existiert nicht mehr
      end;
    end;   // hier error!!!!!!!!!!!!!!!!!
end;

procedure TMenuManager.RemoveButton(Index: Integer);
begin
  Self.FMenuEntries.Del(Index);
end;

procedure TMenuManager.SetActiveButton(const Value: Integer);
  var
    AMenuEntry: TMenuEntry;
begin
  if Value = -1 then
    Exit;
    
  AMenuEntry := Self.FMenuEntries.MenuEntry[Value];

  if (AMenuEntry <> nil) and (Value <> Self.FActiveButton) then begin
    if AMenuEntry.ButtonStyle = etButton then begin
      AMenuEntry.FPanel.Color := clYellow;
      if Self.FActiveButton > -1 then
        Self.FMenuEntries.MenuEntry[Self.FActiveButton].FPanel.Color := clGray;
      Self.FActiveButton := Value;
      end;
    end;
end;

{ TMenuEntries }

function TMenuEntries.Add(AOwner: TWinControl): TMenuEntry;
begin
  Result := inherited Add as TMenuEntry;

  Result.FPanel := TJvPanel.Create(AOwner);
  Result.FPanel.Parent := AOwner;
end;

constructor TMenuEntries.Create;
begin
  inherited Create(TMenuEntry);

end;

procedure TMenuEntries.Del(Index: Integer);
begin
  Self.GetEntry(Index).Free;
end;

destructor TMenuEntries.Destroy;
begin

  inherited Destroy;
end;

function TMenuEntries.GetEntry(Index: Integer): TMenuEntry;
begin
  Result := inherited Items[Index] as TMenuEntry;
end;

{ TMenuEntry }

destructor TMenuEntry.Destroy;
begin
  Self.FPanel.SetFocus;
  Self.FPanel.Free;

  inherited Destroy;
end;

end.

Meine Main Klasse

Delphi-Quellcode:

type
  TMain_Frm = class(TForm)
    procedure MenuManagerClick(Sender: TObject);
  private
    FMenuManager: TMenuManager;
    procedure CenterLoadCore;
    procedure SelectPressed;
  public
    { Public declarations }
  end;

implementation

procedure TMain_Frm.CenterLoadCore;
  var
    XPos: Integer;
    YPos: Integer;
begin
  // Menü erstellen und Position festlegen
  XPos := Trunc(Screen.Width / 14);
  YPos := Trunc(Screen.Height / 5);
  FMenuManager := TMenuManager.Create(Self, XPos, YPos);
  FMenuManager.OnItemClick := Self.MenuManagerClick;

  Self.FMenuManager.AddButton('Musik');
  Self.FMenuManager.AddButton('DVD');
  Self.FMenuManager.AddButton('Video');
  Self.FMenuManager.AddButton('Audio - Radio');
  Self.FMenuManager.AddButton('Video - Radio');
  Self.FMenuManager.AddButton('Playlisten');
  Self.FMenuManager.AddButton('Module');
  Self.FMenuManager.AddButton('Beenden');
  Self.FMenuManager.ButtonActive := 0;
end;

procedure TMain_Frm.MenuManagerClick(Sender: TObject);
begin
  Self.SelectPressed;
end;

procedure TMain_Frm.SelectPressed;
  var
    I: Integer;
begin
  Self.JvLabel1.Caption := Format('Entry: %d', [Self.FMenuManager.ButtonActive]);
  Self.FMenuManager.RemoveButton(Self.FMenuManager.ButtonActive);
  Self.FMenuManager.ClearButtons;
end;

Falls jemand hierfür eine Lösung findet oder vllt einen besseren Vorschlag hat würde ich mich freuen diese zu hören

Gruß

Cyber