Delphi中用多媒体库Bass.dll播放mp3 [7] - 获取当前的播放状态

Delphi中用多媒体库Bass.dll播放mp3 [7] - 获取当前的播放状态2011-04-23 博客园万一本例效果图:
代码文件:
unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;
type
  TForm1 = class（TForm）
   OpenDialog1: TOpenDialog;
   Timer1: TTimer;
   Button1: TButton;
   Button2: TButton;
   Button3: TButton;
   Button4: TButton;
   procedure FormCreate（Sender: TObject）;
   procedure FormDestroy（Sender: TObject）;
   procedure Button1Click（Sender: TObject）;
   procedure Button2Click（Sender: TObject）;
   procedure Button3Click（Sender: TObject）;
   procedure Button4Click（Sender: TObject）;
   procedure Timer1Timer（Sender: TObject）;
  end;
var
  Form1: TForm1;
implementation
{$R *.dfm}
uses Bass;
var
  hs: HSTREAM; {流句柄}
procedure TForm1.FormCreate（Sender: TObject）;
begin
  Timer1.Interval := 200;
  if HiWord（BASS_GetVersion） <> BASSVERSION then
   MessageBox（0, ""Bass.dll" 文件版本不合适！ ", nil, MB_ICONERROR）;
  if not BASS_Init（-1, 44100, 0, 0, nil） then
   ShowMessage（"初始化错误"）;
end;
{打开}
procedure TForm1.Button1Click（Sender: TObject）;
var
  Mp3Path: AnsiString;
begin
  BASS_StreamFree（hs）;
  OpenDialog1.Filter := "Mp3 文件（*.mp3）|*.mp3|Wav 文件（*.wav）|*wav";
  if OpenDialog1.Execute then
   Mp3Path := AnsiString（OpenDialog1.FileName）;
  hs := BASS_StreamCreateFile（False, PAnsiChar（Mp3Path）, 0, 0, 0）;
  {想下面这样建立播放流, 直接就是循环播放的}
  //hs := BASS_StreamCreateFile（False, PAnsiChar（Mp3Path）, 0, 0, BASS_SAMPLE_LOOP）;
  if hs < BASS_ERROR_ENDED then Text := "打开失败"
end;
{播放}
procedure TForm1.Button2Click（Sender: TObject）;
begin
  BASS_ChannelPlay（hs, False）;
end;
{暂停}
procedure TForm1.Button3Click（Sender: TObject）;
begin
  BASS_ChannelPause（hs）;
end;
{停止}
procedure TForm1.Button4Click（Sender: TObject）;
begin
  BASS_ChannelStop（hs）;
end;
{监视播放状态}
procedure TForm1.Timer1Timer（Sender: TObject）;
var
  str: string;
begin
  if hs = 0 then Exit; {如果播放流没有建立则退出}
  case BASS_ChannelIsActive（hs） of
   BASS_ACTIVE_STOPPED: str := "停止状态";
   BASS_ACTIVE_PLAYING: str := "正在播放";
   BASS_ACTIVE_STALLED: str := "失速状态, 正在等待数据";
   BASS_ACTIVE_PAUSED: str := "暂停状态";
  end;
  Text := str;
end;
procedure TForm1.FormDestroy（Sender: TObject）;
begin
  BASS_Free;
end;
end.