这是 FireMonkey 中的错误/未实现的功能吗?
对于这个问题的两个部分都说“不”,尽管将其作为一项功能会很好。这是一种可能的解决方案:
unit MainFrm;
interface
uses
System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Layouts, FMX.Controls.Presentation, FMX.ScrollBox, FMX.Memo, FMX.StdCtrls;
type
TMouseInfo = record
Down: Boolean;
DownPt: TPointF;
Moved: Boolean;
procedure MouseDown(const X, Y: Single);
procedure MouseMove(const X, Y: Single);
procedure MouseUp;
end;
TButton = class(FMX.StdCtrls.TButton)
private
FMouseInfo: TMouseInfo;
protected
procedure Click; override;
procedure MouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Single); override;
procedure MouseMove(Shift: TShiftState; X, Y: Single); override;
procedure MouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Single); override;
end;
TfrmMain = class(TForm)
MessagesMemo: TMemo;
VertScrollBox: TVertScrollBox;
private
procedure ControlClickHandler(Sender: TObject);
public
constructor Create(AOwner: TComponent); override;
end;
var
frmMain: TfrmMain;
implementation
{$R *.fmx}
{ TMouseInfo }
procedure TMouseInfo.MouseDown(const X, Y: Single);
begin
Down := True;
Moved := False;
DownPt := PointF(X, Y);
end;
procedure TMouseInfo.MouseMove(const X, Y: Single);
begin
if Down and not Moved then
Moved := (Abs(X - DownPt.X) > 10) or (Abs(Y - DownPt.Y) > 10);
end;
procedure TMouseInfo.MouseUp;
begin
Down := False;
end;
{ TButton }
procedure TButton.Click;
begin
if not FMouseInfo.Moved then
inherited;
end;
procedure TButton.MouseDown(Button: TMouseButton; Shift: TShiftState; X, Y: Single);
begin
inherited;
FMouseInfo.MouseDown(X, Y);
end;
procedure TButton.MouseMove(Shift: TShiftState; X, Y: Single);
begin
inherited;
FMouseInfo.MouseMove(X, Y);
end;
procedure TButton.MouseUp(Button: TMouseButton; Shift: TShiftState; X, Y: Single);
begin
inherited;
FMouseInfo.MouseUp;
end;
{ TfrmMain }
constructor TfrmMain.Create(AOwner: TComponent);
var
I: Integer;
LButton: TButton;
begin
inherited;
for I := 0 to 29 do
begin
LButton := TButton.Create(Self);
LButton.Name := 'Button' + (I + 1).ToString;
LButton.Width := 120;
LButton.Height := 32;
LButton.Position.X := (Width - LButton.Width) / 2;
LButton.Position.Y := I * 80;
LButton.OnClick := ControlClickHandler;
LButton.Parent := VertScrollBox;
end;
end;
procedure TfrmMain.ControlClickHandler(Sender: TObject);
begin
MessagesMemo.Lines.Add(TComponent(Sender).Name + ' was clicked');
end;
end.
在这里,我使用通常被称为从 TButton 派生的“插入器”类来重写检测鼠标是否已移动所需的方法,以便仅在鼠标未移动(非常移动)时调用 Click。当按钮接收到 MouseDown 时,会设置 Down 标志并设置位置,然后当接收到 MouseMove 时,它会计算它移动了多远。如果太远,当最终调用 Click 时,不会调用继承的方法,因此不会触发 OnClick 事件。
您可以对 TRectangle 或任何可以接收点击的内容使用相同的技术