任意改变FMX的TPanel控件的颜色

FMX的控件的外观以Style为主，但是也有不方便的地方，比如要任意改变TPanel的颜色，只能写代码，摸索了几天，初步实现了

unit FMX.JKPanelEx;


interface


uses
  System.SysUtils, System.Classes, System.Types, System.UITypes, FMX.Types, FMX.Controls, FMX.Objects, FMX.Graphics,
  FMX.Controls.Presentation, FMX.StdCtrls;


type
  TAppearanceUpdateKind = (None, Fill, Stroke, CornerSize);


  TJKPanelEx = class(TPanel)
  private
    FAppearance: TRectangle;
    FFill: TBrush;
    FStroke: TStrokeBrush;
    FCornerSize: Single;
    FAppearanceUpdateKind: TAppearanceUpdateKind;
    procedure SetFill(const Value: TBrush);
    procedure SetStroke(const Value: TStrokeBrush);
    procedure SetCornerSize(const Value: Single);


  protected
    procedure ApplyStyle; override;
    procedure FreeStyle; override;
    procedure FillChanged(Sender: TObject); virtual;
    procedure StrokeChanged(Sender: TObject); virtual;
    procedure UpdateAppearanceFill;
    procedure UpdateAppearanceStroke;
    procedure UpdateAppearanceCornerSize;
    procedure UpdateAppearance;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;


    property Appearance: TRectangle read FAppearance write FAppearance;
  published
    property Fill: TBrush read FFill write SetFill;
    property Stroke: TStrokeBrush read FStroke write SetStroke;
    property CornerSize: Single read FCornerSize write SetCornerSize;
  end;


procedure Register;


implementation


procedure Register;
begin
  RegisterComponents('JKFMXControl', [TJKPanelEx]);
end;


{ TJKPanelEx }


procedure TJKPanelEx.ApplyStyle;
begin
  inherited;
  if not Assigned(FAppearance) then
  begin
    if not FindStyleResource<TRectangle>('Background', FAppearance) and (ResourceControl is TRectangle) then
      FAppearance := TRectangle(ResourceControl);
    UpdateAppearanceCornerSize;
    UpdateAppearanceFill;
    UpdateAppearanceStroke;
  end
  else
  begin
    UpdateAppearance;
  end;
end;


constructor TJKPanelEx.Create(AOwner: TComponent);
begin
  inherited;
  FAppearance := nil;
  FAppearanceUpdateKind := TAppearanceUpdateKind.None;
  FFill := TBrush.Create(TBrushKind.Solid, TAlphaColor($FFE0E0E0));
  FStroke := TStrokeBrush.Create(TBrushKind.Solid, TAlphaColors.Black);
  FFill.OnChanged := FillChanged;
  FStroke.OnChanged := StrokeChanged;
end;


destructor TJKPanelEx.Destroy;
begin
  FreeAndNil(FFill);
  FreeAndNil(FStroke);
  inherited;
end;


procedure TJKPanelEx.FillChanged(Sender: TObject);
begin
  FAppearanceUpdateKind := TAppearanceUpdateKind.Fill;
  ApplyStyle;
end;


procedure TJKPanelEx.FreeStyle;
begin
  inherited;
  FAppearance := nil;
end;




procedure TJKPanelEx.SetCornerSize(const Value: Single);
begin
  if FCornerSize <> Value then
  begin
    FAppearanceUpdateKind := TAppearanceUpdateKind.CornerSize;
    FCornerSize := Value;
    UpdateAppearanceCornerSize;
  end;
end;


procedure TJKPanelEx.SetFill(const Value: TBrush);
begin
  FFill.Assign(Value);
end;


procedure TJKPanelEx.SetStroke(const Value: TStrokeBrush);
begin
  FStroke.Assign(Value);
end;


procedure TJKPanelEx.StrokeChanged(Sender: TObject);
begin
  FAppearanceUpdateKind := TAppearanceUpdateKind.Stroke;
  ApplyStyle;
end;


procedure TJKPanelEx.UpdateAppearance;
begin
  case FAppearanceUpdateKind of
    TAppearanceUpdateKind.None: ;
    TAppearanceUpdateKind.Fill: UpdateAppearanceFill;
    TAppearanceUpdateKind.Stroke: UpdateAppearanceStroke;
    TAppearanceUpdateKind.CornerSize: UpdateAppearanceCornerSize;
  end;
end;


procedure TJKPanelEx.UpdateAppearanceFill;
begin
  if FAppearance <> nil then
  begin
    FAppearance.Fill.Assign(FFill);
  end;
end;


procedure TJKPanelEx.UpdateAppearanceStroke;
begin
  if FAppearance <> nil then
  begin
    FAppearance.Stroke.Assign(FStroke);
  end;
end;


procedure TJKPanelEx.UpdateAppearanceCornerSize;
begin
  if FAppearance <> nil then
  begin
    FAppearance.XRadius := FCornerSize;
    FAppearance.YRadius := FCornerSize;
  end;
end;


end.