aniedit.pas

《Delphi 7经典问题解析》源代码 第一到七章 基础篇源程序 应用篇源程序

unit AniEdit;
interface
uses
  Windows, Messages, SysUtils, Classes, Controls, Forms, StdCtrls, ExtCtrls, Graphics;
type
  TAniEdit = class(TEdit)
  private
    FInterval: Integer;
    FTimer: TTimer;
    procedure MoveShow(Sender: TObject);
  public
    constructor Create(AOwner: TComponent);
    procedure StartAni;
    procedure StopAni;
  published
    property Interval: Integer read FInterval write FInterval;
  end;
procedure Register;

implementation

constructor TAniEdit.Create(AOwner: TComponent);
begin
  inherited create(aowner);
  color := clBlack;
  font.Color := clWhite;
  font.Size := 12;
  font.Name := '仿宋_GB2312';
  tabstop := false;
  update;
  FTimer := TTimer.Create(self);
  FTimer.Enabled := False;
  FTimer.OnTimer := MoveShow;
  FInterval := 1000;
end;

procedure TAniEdit.StartAni;
begin
  FTimer.Interval := FInterval;
  FTimer.Enabled := True;
end;

procedure TAniEdit.StopAni;
begin
  FTimer.Enabled := False;
end;

procedure TAniEdit.MoveShow(Sender: TObject);
var
  edit_length, i: integer;
  edit_char: char;
  chars: string;
begin
  chars := '';
  if (length(text) = 0) then //如果编辑框中没有字符串，就默认赋值
    text := 'Welcom you to use the software!';
  edit_length := length(text);
  edit_char := text[1];
  //判断首字符是英文字母还是汉字
  if (Ord(edit_char) > 127) then
  begin
    //如果是汉字就拷贝两个字符，代表一个汉字
    chars := copy(text, 1, 2);
    text := copy(text, 3, edit_length - 1) + chars;
  end
  else
    //如果是英文字符的话，就拷贝一个字符
    text := copy(text, 2, edit_length - 1) + edit_char;
end;

procedure Register;
begin
  RegisterComponents('Samples', [TAniEdit]);
end;
end.