unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, StdCtrls;

type
  TCallBack = Procedure(Const Content:String) of object;
  TTestThread=Class(TThread)
  Private
    FS:String;
    FCallBack:TCallBack;
    procedure Showtext;
  public
    constructor Create( CreateSuspended : Boolean;CallBack:TCallBack );overload;
    destructor Destroy; override;
    Procedure Execute; override;
  End;

  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    procedure CallBack(const s: String);

  public

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.CallBack(Const s:String);
begin
  Memo1.Lines.Add(s)
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
    TTestThread.Create(false,CallBack);
end;

{ TTestThread }



constructor TTestThread.Create(CreateSuspended: Boolean;CallBack:TCallBack);
begin
  inherited Create(CreateSuspended);
  FreeOnTerminate := true;
  FCallBack := CallBack;
end;

destructor TTestThread.Destroy;
begin

  inherited;
end;

procedure TTestThread.Showtext;
begin
 if Assigned(FCallBack) then FCallBack(FS);
end;

procedure TTestThread.Execute;
var
IdHTTP1 : TIdHTTP;
ss:TStringStream;
begin
  inherited;
    ss:=TStringStream.Create;
    IdHTTP1:= TIdHTTP.Create(nil);
    try
    IdHTTP1.Get('http://www.google.de',ss);
    ss.Position := 0;
    FS := ss.ReadString(ss.Size);
    Synchronize(Showtext);
    finally
      ss.Free;
      IdHTTP1.Free;
    end;
end;

end.