如何实现Mid的循环播放
问题点数：21、回复次数：1Top
1 楼Bob7946（X度空间）回复于 2001-11-10 17:56:01 得分 21
下面的程序我已实际编译运行过，随便你暂停多少次，都可以再次循环播放
unit Unit1;
interface
uses
Windows, Messages, mmsystem,SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
protected
procedure MCINotify(Var Message:TMessage);Message MM_MCINOTIFY;
private
function SendMCIStr(Const Value:String):PChar;
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
begin
SendMciStr('Open C:\123.mid alias mid');
SendMciStr('Play mid notify');
end;
procedure TForm1.MCINotify(var Message: TMessage);
begin
if SendMciStr('Status mid mode')='stopped' then
begin
SendMciStr('Seek mid to start');
SendMciStr('Play mid notify');
end;
end;
function TForm1.SendMCIStr(const Value: String):PChar;
Var Buf:Array[0..4095] of char;
begin
MCISendString(PChar(Value),Buf,Sizeof(Buf),Handle);
Result:=Buf;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
SendMCiStr('Pause mid notify');
end;
procedure TForm1.Button3Click(Sender: TObject);
begin
SendMCiStr('Play mid notify');
end;
procedure TForm1.Button4Click(Sender: TObject);
begin
SendMciStr('Close mid');
end;
end.
回复人：yeah(2000-8-22 1:39:00) 得0分
下面的程序我已实际编译运行过，随便你暂停多少次，都可以再次循环播放，
其中Button1为打开并播放，Button2为暂停,Button3恢复,Button4关闭。
unit Unit1;
interface
uses
Windows, Messages, mmsystem,SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
protected
procedure MCINotify(Var Message:TMessage);Message MM_MCINOTIFY;
private
function SendMCIStr(Const Value:String):PChar;
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
begin
SendMciStr('Open C:\123.mid alias mid');
SendMciStr('Play mid notify');
end;
procedure TForm1.MCINotify(var Message: TMessage);
begin
if SendMciStr('Status mid mode')='stopped' then
begin
SendMciStr('Seek mid to start');
SendMciStr('Play mid notify');
end;
end;
function TForm1.SendMCIStr(const Value: String):PChar;
Var Buf:Array[0..4095] of char;
begin
MCISendString(PChar(Value),Buf,Sizeof(Buf),Handle);
Result:=Buf;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
SendMCiStr('Pause mid notify');
end;
procedure TForm1.Button3Click(Sender: TObject);
begin
SendMCiStr('Play mid notify');
end;
procedure TForm1.Button4Click(Sender: TObject);
begin
SendMciStr('Close mid');
end;
end.
回复人：drmy(2000-8-22 21:43:00) 得0分
奇怪的事情发生了。yeah兄你的程序完全正确，不过条件是运行在Windows98下，我测试过了。但是在Windows2000下如果按过pause和resume就会无法再循环播放了。我主要使用Windows2000，还请再费心了，谢谢。
回复人：yeah(2000-8-23 0:16:00) 得23分
今天看到drmy的留言，我急忙装上Win2K（开玩笑）*_^，在D5中运行一遍，果然
不行，于是代码改成这样，别说你又用D4，我要晕倒了:)
unit Unit1;
interface
uses
Windows, Messages, mmsystem,SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
protected
procedure MCINOTIFY(Var Message:TMessage); message MM_MCINOTIFY;
private
nowloop:boolean;
function SendMCIStr(Const Msg:String):PChar;
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
{打开并播放}
procedure TForm1.Button1Click(Sender: TObject);
begin
SendMciStr('open c:\123.mid alias mid');
Sendmcistr('play mid notify');
Nowloop:=true;
end;
{Callback}
procedure TForm1.MCINOTIFY(var Message: TMessage);
begin
if nowloop and (SendmciStr('Status mid mode')='stopped') then
begin
sendmcistr('seek mid to start');
sendmcistr('play mid notify');
end;
end;
{暂停(实际上是停止，但效果一样)}
procedure TForm1.Button2Click(Sender: TObject);
begin
nowloop:=False;
mcisendstring('stop mid',nil,0,0);
end;
{恢复(实际上是从当前位置播放，效果一样,
因为SEQ设备不支持Resume命令)}
procedure TForm1.Button3Click(Sender: TObject);
begin
nowloop:=true;
sendmcistr('play mid notify');
end;
{关闭}
procedure TForm1.Button4Click(Sender: TObject);
begin
sendmcistr('close mid');
end;
{公用函数}
function TForm1.SendMCIStr(const Msg: String): PChar;
Var Buf:Array[0..4095] of Char;
begin
MciSendString(PChar(msg),Buf,sizeof(buf),Handle);
Result:=Buf;
end;
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
button4click(nil);
end;
end.
前面那个程序在Win2k不行的原因，我跟踪了一下，原来在Win2k下的Callback中，
只要发送了Pause命令，下次再调用play，在Callback中mode仍为paused，所以就
不能循环喽。Top
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