Delphi 接口-接口和面向对象编程

Posted 2021-01-15 yishen

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unit uSayHello;

interface

uses    
    SysUtils,
    Windows,
    Messages,
    Greaphics,
    Controls,
    Forms,
    Dialogs;

type 

IGreetable = interface
    [‘|0000-0000-0000-0000|‘]
    function SayHello: PChar;
end;

TMan = class(TInterfacedObject,IGreetable)
    Language: string;
    Married: Boolean;
    Name: string;
    SkinColor: string;
    constructor create; virtual;
    function SayHello: PChar; virtual; abstract;
end;

TChinese = class(TMan)
public  
    constructor create; override;
private
    function SayHello: PChar; override;
end;

TAmerican = class(TMan)
public
    constructor create; override;
private 
    function SayHello: PChar; override;
end;

TFrnch = class(TMan)
public
    constructor create; override;
private
    function SayHello: pchar ;override;
end;

TKorean = class(TMan)
public
    constructor create; override;
private
    function SayHello: pchar ; override;
end;

TET = class(TInterfacedObject,IGreetable)
private
    function SayHello: pchar;
end;

TRobot = class(TInterfacedObject,Igreetable)
private
    function SayHello: pchar;
end;

implementation

constructor TMan.create;
begin
  Name := ‘张三‘;
  Language := ‘中文‘;
  SkinColor := ‘yellow‘;
end;

constructor TChinese.create;
begin
    inherited;
end;

constructor TAmerican.create;
begin
    Name := ‘Lee‘;
    Language := ‘English‘;
    SkinColor := ‘black‘;
end;

constructor TFrnch.create;
begin
    Name:=‘苏菲‘;
    Language := ‘法文‘;
    SkinColor := ‘white‘;
end;

constructor TKorean.create;
begin
    Name := ‘韩国‘;
    Language := ‘韩文‘;
    SkinColor := ‘yellow‘;
end;

function TChinese.SayHello;
begin
    result := ‘中国人:你好!‘;
end;

function TAmerican.SayHello;
begin
    result := ‘American:Hello!‘;
end;

function TFrench.SayHello;
begin
    result := ‘法国人:你好‘;
end;

function TKorean.SayHello;
begin   
    result := ‘韩国人:你好‘;
end;

function TET.SayHello;
begin
    result := ‘TET:你好‘;
end;

function TRobot.SayHello;
begin
    result := ‘Robot:你好‘;
end;

unit uFromSayHello

uses    
    //...

type
TFormSayHello = class(TForm)
    btnUSA: TButton;
    btnKorean: TButton;
    btnCN: TButton;
    btnFrench: TButton;
    btnET: TButton;
    btnRobott: TButton;
    procedure btnUSAClick(Sender: TObject);
    procedure btnKoreanClick(Sender: TObject);
    procedure btnCNClick(Sender: TObject);
    procedure btnFrenchClick(Sender: TObject);
    procedure btnETClick(Sender: TObject);
    procedure btnRobottClick(Sender: TObject);
end;

procedure TFormSayHello.SayHello(greeting: IGreetable);
begin
    ShoeMessage(greeting.SayHello);
end;

procedure TFormSayHello.btnKoreanClick(Sender: TObject);
begin
    SayHello(TKorean.create);
end;

procedure TFormSayHello.btnCNClick(Sender: TObject);
begin
    SayHello(TChinese.create);
end;

procedure TFormSayHello.btnFrenchClick(Sender: TObject);
begin
    SayHello(TFrench.create);
end;

procedure TFormSayHello.btnETClick(Sender: TObject);
begin
    SayHello(TET.create);
end;

procedure TFormSayHello.btnRobottClick(Sender: TObject);
begin
    SayHello(TRobot.create);
end;

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//进一步修改
unit uSayHello;

interface

uses    
    SysUtils,
    Windows,
    Messages,
    Greaphics,
    Controls,
    Forms,
    Dialogs;

type 

IGreetable = interface
    [‘|0000-0000-0000-0000|‘]
    function SayHello: PChar;
end;

TMan = class(TInterfacedObject,IGreetable)
    Language: string;
    Married: Boolean;
    Name: string;
    SkinColor: string;
    constructor create; virtual;
    function SayHello: PChar; virtual; abstract;
end;

TChinese = class(TMan)
public  
    constructor create; override;
private
    function SayHello: PChar; override;
end;

TAmerican = class(TMan)
public
    constructor create; override;
private 
    function SayHello: PChar; override;
end;

TFrnch = class(TMan)
public
    constructor create; override;
private
    function SayHello: pchar ;override;
end;

TKorean = class(TMan)
public
    constructor create; override;
private
    function SayHello: pchar ; override;
end;

TET = class(TInterfacedObject,IGreetable)
private
    function SayHello: pchar;
end;

TRobot = class(TInterfacedObject,Igreetable)
private
    function SayHello: pchar;
end;

implementation

constructor TMan.create;
begin
  Name := ‘张三‘;
  Language := ‘中文‘;
  SkinColor := ‘yellow‘;
end;

constructor TChinese.create;
begin
    inherited;
end;

constructor TAmerican.create;
begin
    Name := ‘Lee‘;
    Language := ‘English‘;
    SkinColor := ‘black‘;
end;

constructor TFrnch.create;
begin
    Name:=‘苏菲‘;
    Language := ‘法文‘;
    SkinColor := ‘white‘;
end;

constructor TKorean.create;
begin
    Name := ‘韩国‘;
    Language := ‘韩文‘;
    SkinColor := ‘yellow‘;
end;

function TChinese.SayHello;
begin
    result := ‘中国人:你好!‘;
end;

function TAmerican.SayHello;
begin
    result := ‘American:Hello!‘;
end;

function TFrench.SayHello;
begin
    result := ‘法国人:你好‘;
end;

function TKorean.SayHello;
begin   
    result := ‘韩国人:你好‘;
end;

function TET.SayHello;
begin
    result := ‘TET:你好‘;
end;

function TRobot.SayHello;
begin
    result := ‘Robot:你好‘;
end;

unit uFromSayHello

uses    
    //...

type
TFormSayHello = class(TForm)
    btnUSA: TButton;
    btnKorean: TButton;
    btnCN: TButton;
    btnFrench: TButton;
    btnET: TButton;
    btnRobott: TButton;
    procedure btnUSAClick(Sender: TObject);
    procedure btnKoreanClick(Sender: TObject);
    procedure btnCNClick(Sender: TObject);
    procedure btnFrenchClick(Sender: TObject);
    procedure btnETClick(Sender: TObject);
    procedure btnRobottClick(Sender: TObject);
end;

procedure TFormSayHello.SayHello(greeting: IGreetable);
begin
    ShowMessage(greeting.SayHello);
end;

//人类问候
procedure TFormSayHello.SayHello(AMan: TMan)
begin
    editName.text := AMan.Name;
    editLanguage.text := AMan.Language;
    editSkinColor.text := AMan.SkinColor;
    ShowMessage(AMan.SayHello);
end;

//这里新增来自非人类的另类问候方式.
//通过方法重载,使得程序的改动降低到最少.
procedure TFormSayHello.SayHello(greeting: Igreetable)
begin
    editName.text := copy(greeting.SayHello,1,6);
    editLanguage.text := copy(greeting.SayHello,7,4);
    editSkinColor.text := copy(greeting.SayHello,11,6);
    ShowMessage(greeting.SayHello);
end;

procedure TFormSayHello.btnKoreanClick(Sender: TObject);
begin
    SayHello(TKorean.create);
end;

procedure TFormSayHello.btnCNClick(Sender: TObject);
begin
    SayHello(TChinese.create);
end;

procedure TFormSayHello.btnFrenchClick(Sender: TObject);
begin
    SayHello(TFrench.create);
end;

procedure TFormSayHello.btnETClick(Sender: TObject);
begin
    SayHello(TET.create);
end;

procedure TFormSayHello.btnRobottClick(Sender: TObject);
begin
    SayHello(TRobot.create);
end;

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