unit1.pas

mp3播放器的delphi设计

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls, PubUnit;

type
  TFrm_Main = class(TForm)
    Panel1: TPanel;
    OpenBtn: TButton;
    PlayBtn: TButton;
    PauseBtn: TButton;
    StopBtn: TButton;
    ExitBtn: TButton;
    Label1: TLabel;
    Label2: TLabel;
    FreqLabel: TLabel;
    LengthLabel: TLabel;
    OpenDialog1: TOpenDialog;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure OpenBtnClick(Sender: TObject);
    procedure PlayBtnClick(Sender: TObject);
    procedure PauseBtnClick(Sender: TObject);
    procedure StopBtnClick(Sender: TObject);
    procedure ExitBtnClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Frm_Main: TFrm_Main;

implementation

{$R *.DFM}

//Init mp3
//hInstance:  instance of application
//hWnd:  handle of window to display
//DisplayW, DisplayH: width and height
//bands: number of bars
function pvInitMp3(hInstance, hWnd, DisplayW, DisplayH, bands: integer): integer; stdcall; external 'pvmp3.dll';
//free. MUST call this before exit
procedure pvFreeMp3; stdcall; external 'pvmp3.dll';
//get the frequence and length of mp3
procedure pvGetMp3Info(pFileName: PChar; pFreq, pLen: pointer); stdcall; external 'pvmp3.dll';
//play mp3
function pvPlayMp3(pFileName: PChar): integer; stdcall; external 'pvmp3.dll';
//stop mp3
procedure pvStopMp3; stdcall; external 'pvmp3.dll';
//pasue mp3
procedure pvPauseMp3; stdcall; external 'pvmp3.dll';
//resume mp3
procedure pvResumeMp3; stdcall; external 'pvmp3.dll';

procedure TFrm_Main.FormCreate(Sender: TObject);
begin
  pvInitMp3(hInstance, Panel1.Handle, Panel1.Width, Panel1.Height, 32);
end;

procedure TFrm_Main.FormDestroy(Sender: TObject);
begin
  pvFreeMp3;
end;

procedure TFrm_Main.OpenBtnClick(Sender: TObject);
var
  freq, len: integer;
  s: string;
begin
  if OpenDialog1.Execute then
  begin
    pvStopMp3;
    pvGetMp3Info(pchar(OpenDialog1.FileName), @freq, @len);
    Freqlabel.Caption := IntToStr(freq);
    s := GetStringFromFrame(len*25);
    SetLength(s, length(s)-3);
    LengthLabel.Caption := s;

    PlayBtn.Enabled := True;
    PauseBtn.Enabled := True;
    StopBtn.Enabled := True;
    PauseBtn.tag := 0;
    PauseBtn.Caption := 'P&ause';
  end;
end;

procedure TFrm_Main.PlayBtnClick(Sender: TObject);
begin
  pvPlayMp3(PChar(OpenDialog1.FileName));
  PauseBtn.tag := 0;
  PauseBtn.Caption := 'P&ause';
end;

procedure TFrm_Main.PauseBtnClick(Sender: TObject);
begin
  if PauseBtn.tag=0 then
  begin
    PauseBtn.tag := 1;
    PauseBtn.Caption := '&Resume';
    pvPauseMp3;
  end else begin
    PauseBtn.tag := 0;
    PauseBtn.Caption := 'P&ause';
    pvResumeMp3;
  end;
end;

procedure TFrm_Main.StopBtnClick(Sender: TObject);
begin
  pvStopMp3;
  PauseBtn.tag := 0;
  PauseBtn.Caption := 'P&ause';
end;

procedure TFrm_Main.ExitBtnClick(Sender: TObject);
begin
  Close;
end;

end.