uphotomgr.pas

观察者模式delphi实例实现,同时注意软件的设计

unit uPhotoMgr;

interface
uses
    Windows, Messages, SysUtils, Graphics, Forms, Dialogs, Controls, classes
    , uInterface;

type
    TPhotoMgr = class(TObject, IPhotoMgr)
    private
        flist: TInterfaceList;

    private
        //实现IUnknown接口
        function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
        function _AddRef: Integer; stdcall;
        function _Release: Integer; stdcall;
        //实现IPhotoMgr接口
        function GetPhotoCount(var Count:Integer):Boolean;
        function GetPhotoID(const idx:Integer; var PhotoID:Integer):Boolean;
        function GetSelPhotoID(var PhotoID:Integer):Boolean;
        function GetPhotoPorp(const photoID:Integer;var PhotoProp:TPhotoProp):Boolean;
        function GetBmp(const PhotoID:Integer;var bmp:TBitmap):Boolean;

        //事件通知
        function SelPhoto(const photoID:Integer):Boolean;
        function NewPhoto(const photoID:Integer):Boolean;
        function DelPhoto(const photoID:Integer):Boolean;
        function Refresh():Boolean;
        function PropChange(const photoID:Integer):Boolean;

    public
        constructor Create;
        destructor destroy;override;
        //加入通知接口
        procedure AddNotify(notify:IPhotoNotify);
        procedure Newp;
    end;

implementation

{ TPhotoMgr }

constructor TPhotoMgr.Create;
begin
    flist := TInterfaceList.Create;
    _AddRef;
end;

{------------------------------------------------------------------------------}
destructor TPhotoMgr.destroy;
begin
    flist.Free;
    inherited;
end;

{//////////////////////////////////////////////////////////////////////////////}
procedure TPhotoMgr.AddNotify(notify: IPhotoNotify);
begin
    flist.Add(notify);
end;

{//////////////////////////////////////////////////////////////////////////////}
//实现IUNKnown接口
function TPhotoMgr._AddRef: Integer;
begin
    Result := -1;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr._Release: Integer;
begin
    Result := -1;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
  if GetInterface(IID, Obj) then
    Result := 0
  else
    Result := E_NOINTERFACE;
end;

{//////////////////////////////////////////////////////////////////////////////}
//实现IPhotoMgr接口
function TPhotoMgr.GetBmp(const PhotoID: Integer; var bmp: TBitmap): Boolean;
begin

end;

{------------------------------------------------------------------------------}
function TPhotoMgr.GetPhotoCount(var Count: Integer): Boolean;
begin
    Count := 100;
    Result := True;
end;

function TPhotoMgr.GetPhotoID(const idx: Integer; var PhotoID: Integer): Boolean;
begin

end;

function TPhotoMgr.GetPhotoPorp(const photoID: Integer;  var PhotoProp: TPhotoProp): Boolean;
begin

end;

function TPhotoMgr.GetSelPhotoID(var PhotoID: Integer): Boolean;
begin

end;

{//////////////////////////////////////////////////////////////////////////////}
//发送事件通知
function TPhotoMgr.DelPhoto(const photoID: Integer): Boolean;
var
    i:Integer;
begin

    Result := False;
    if flist.Count = 0 then Exit;
    for i := 0 to flist.Count -1 do
    begin
        if not IPhotoNotify(flist.Items[i]).DelPhoto(photoID) then
            Break;
    end;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr.NewPhoto(const photoID: Integer): Boolean;
var
    i:Integer;
begin

    Result := False;
    if flist.Count = 0 then Exit;
    for i := 0 to flist.Count -1 do
    begin
        if not IPhotoNotify(flist.items[i]).NewPhoto(photoID) then
            Break;
    end;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr.PropChange(const photoID: Integer): Boolean;
var
    i:Integer;
begin

    Result := False;
    if flist.Count = 0 then Exit;
    for i := 0 to flist.Count -1 do
    begin
        if not IPhotoNotify(flist.items[i]).PropChange(photoID) then
            Break;
    end;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr.Refresh: Boolean;
var
    i:Integer;
begin

    Result := False;
    if flist.Count = 0 then Exit;
    for i := 0 to flist.Count -1 do
    begin
        if not IPhotoNotify(flist.items[i]).Refresh then
            Break;
    end;
end;

{------------------------------------------------------------------------------}
function TPhotoMgr.SelPhoto(const photoID: Integer): Boolean;
var
    i:Integer;
begin
    Result := False;
    if flist.Count = 0 then Exit;
    for i := 0 to flist.Count -1 do
    begin
        if not IPhotoNotify(flist.items[i]).SelPhoto(photoID) then
            Break;
    end;
end;

{------------------------------------------------------------------------------}
procedure TPhotoMgr.Newp;
begin
    NewPhoto(12345);
end;
end.