📄 c++ builder 程序设计实用教程 - 8_3 midi音乐播放器 - 张晋 - 17xie.htm
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107</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>Width
= 329</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 232</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Caption = 'Form1'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnCreate = FormCreate</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object MediaPlayer1: TMediaPlayer</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 32</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 24</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 253</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 41</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>FileName = </SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>'c:\Windows\system\sound\Fmtest.mid'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object ScrollBar1: TScrollBar</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 32</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 72</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 249</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 25</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>LargeChange = 5</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnScroll = ScrollBar1Scroll</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object Button1: TButton</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 32</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 112</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 81</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 25</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Caption = '</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">打开</SPAN><SPAN
lang=EN-US>'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnClick = Button1Click</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object Button2: TButton</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 32</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 152</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 81</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 25</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Caption = '</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">播放</SPAN><SPAN
lang=EN-US>'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnClick = Button2Click</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object Button3: TButton</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 200</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 112</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 81</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 25</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Caption = '</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">暂停</SPAN><SPAN
lang=EN-US>'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnClick = Button3Click</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object Button4: TButton</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 200</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 152</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Width = 81</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Height = 25</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Caption = '</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">停止</SPAN><SPAN
lang=EN-US>'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnClick = Button4Click</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object Timer1: TTimer</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Interval = 100</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>OnTimer = Timer1Timer</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 144</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 112</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>object OpenDialog1: TOpenDialog</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Filter = 'MIDI</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">音乐文件</SPAN><SPAN
lang=EN-US>(*.mid)|*.mid'</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Left = 144</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Top = 152</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>end</SPAN></P>
<P class=a1><SPAN lang=EN-US>end</SPAN></P>
<H4><SPAN lang=EN-US>3</SPAN><SPAN
style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">．程序的初始化</SPAN></H4>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在程序的设计阶段，用鼠标的左键双击窗体的空白处，在屏幕上就会弹出一个代码窗口，把光标移动到窗体的</SPAN><SPAN
lang=EN-US>FormCreate()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件处理代码中，并且添加如下所示的程序初始化代码：</SPAN></P>
<P class=a1><SPAN lang=EN-US>void __fastcall TForm1::FormCreate(TObject
*Sender)</SPAN></P>
<P class=a1><SPAN lang=EN-US>{</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->Timer1->Enabled=false;</SPAN></P>
<P class=a1><SPAN lang=EN-US>//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置计时器工作状态</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->Button2->Enabled=false;</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->Button3->Enabled=false;</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->Button4->Enabled=false;</SPAN></P>
<P class=a1><SPAN lang=EN-US>//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置按钮有效状态</SPAN></P>
<P class=a1><SPAN lang=EN-US>}</SPAN></P>
<P class=a1><SPAN
lang=EN-US>//-----------------------------------------------------------------------</SPAN></P>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序说明：</SPAN></P>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">窗体</SPAN><SPAN
lang=EN-US>FormCreate</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件中的代码在程序运行初期就会被执行，由于在程序刚刚开始运行时还没有选择有效的音乐文件，所以</SPAN><SPAN
lang=EN-US>Timer1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件的有效状态设置为无效，然后通过三条语句：</SPAN></P>
<P class=MsoNormalIndent><SPAN
lang=EN-US>Form1->Button2->Enabled=false;</SPAN></P>
<P class=MsoNormalIndent><SPAN
lang=EN-US>Form1->Button3->Enabled=false;</SPAN></P>
<P class=MsoNormalIndent><SPAN lang=EN-US>Form1->Button
4->Enabled=false;</SPAN></P>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置按钮组件的有效状态。</SPAN></P>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">经过以上初始化处理后的窗体如图</SPAN><SPAN
lang=EN-US>8-20</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所示。</SPAN></P>
<P class=a><SPAN lang=EN-US><IMG height=205
src="C++ Builder 程序设计实用教程 - 8_3 MIDI音乐播放器 - 张晋 - 17xie.files/0e60d90447.jpg"
width=290 v:shapes="_x0000_i1026"></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.0pt"><o:p></o:p></SPAN></P>
<P class=MsoCaption><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">图</SPAN><SPAN
lang=EN-US>8-20<SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序初始化后的窗体</SPAN></P>
<H4><SPAN lang=EN-US>4</SPAN><SPAN
style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">．打开一个音乐文件</SPAN></H4>
<P class=MsoNormalIndent><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在“打开文件”的按钮上双击鼠标的左键，就会弹出一个代码窗口，在其中就可以添加对按钮“打开文件”的响应代码如下所示。</SPAN></P>
<P class=a1><SPAN lang=EN-US>void __fastcall TForm1::Button1Click(TObject
*Sender)</SPAN></P>
<P class=a1><SPAN lang=EN-US>{</SPAN></P>
<P class=a1><SPAN
lang=EN-US>Form1->OpenDialog1->InitialDir="e:\\midi";</SPAN></P>
<P class=a1><SPAN lang=EN-US>//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置对话框缺省路径</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->OpenDialog1->Title="</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">请选择一个音乐文件名</SPAN><SPAN
lang=EN-US>:";</SPAN></P>
<P class=a1><SPAN lang=EN-US>//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置对话框标题</SPAN></P>
<P class=a1><SPAN
lang=EN-US>Form1->OpenDialog1->DefaultExt="mid";</SPAN></P>
<P class=a1><SPAN lang=EN-US>//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置对话框缺省文件名</SPAN></P>
<P class=a1><SPAN lang=EN-US>if (Form1->OpenDialog1->Execute())</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>{</SPAN></P>
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