📄 c++ builder 程序设计实用教程 - 8_4 视频播放程序 - 张晋 - 17xie.htm
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<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'">设置组件有效状态</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'">在开始执行程序时，系统首先激活窗体的</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，然后通过代码</SPAN><SPAN
lang=EN-US>Form1->MediaPlayer1->Display=Form1->Panel1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；设置动画播放的容器是窗体上的</SPAN><SPAN
lang=EN-US>Panel1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件，最后通过</SPAN><SPAN
lang=EN-US>Form1->ScrollBar1->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Timer1->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button 1->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button2->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button3->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form 1->Button4->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button5->Enabled=false</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button6->Enabled=fal se</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN><SPAN
lang=EN-US>Form1->Button7->Enabled=false;</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN
lang=EN-US>Form1->Button8->Enabled=true;</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设置了窗体上各个组件的有效状态和可见状态。</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>8-23</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=258
src="C++ Builder 程序设计实用教程 - 8_4 视频播放程序 - 张晋 - 17xie.files/40267e0bc1.jpg"
width=271 v:shapes="_x0000_i1026"></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>8-23<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'">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'">．响应计时器事件</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'">窗体上</SPAN><SPAN
lang=EN-US>Timer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件的作用是为程序运行提供时间控制，如随时显示动画文件播放进度等，为此就需要在程序的运行阶段将</SPAN><SPAN
lang=EN-US>Timer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件设置为有效的状态，并且为组件指定一个响应的时间长度。在本示例程序中，</SPAN><SPAN
lang=EN-US>Timer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件的时间控制设置为</SPAN><SPAN
lang=EN-US>100</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，它的意思是在程序运行的过程中，每隔</SPAN><SPAN
lang=EN-US>100</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">毫秒就会自动的激活一个</SPAN><SPAN
lang=EN-US>Timer1Timer()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件，为了在程序中动态的显示动画文件播放的进度，可以在程序设计的过程中用鼠标双击窗体中的</SPAN><SPAN
lang=EN-US>Timer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件，在屏幕上就会弹出一个如图</SPAN><SPAN
lang=EN-US>8-24</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所示的代码窗口。</SPAN></P>
<P class=a><SPAN lang=EN-US><IMG height=222
src="C++ Builder 程序设计实用教程 - 8_4 视频播放程序 - 张晋 - 17xie.files/aba55ff166.jpg"
width=318 v:shapes="_x0000_i1027"></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>8-24<SPAN style="mso-spacerun: yes"> </SPAN>Timer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件的代码窗口</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'">将光标移动到代码窗口中的</SPAN><SPAN
lang=EN-US>Timer1Timer()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件中，并且在它的事件处理中添加下列代码：</SPAN></P>
<P class=a1><SPAN lang=EN-US>void __fastcall TForm1::Timer1Timer(TObject
*Sender)</SPAN></P>
<P class=a1><SPAN lang=EN-US>{</SPAN></P>
<P class=a1><SPAN
lang=EN-US>Form1->ScrollBar1->Position=Form1->MediaPlayer1->Position;</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'">显示动画播放进度</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'">由于组件属性设置的原因，在程序的执行过程中，每隔</SPAN><SPAN
lang=EN-US>100</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">毫秒的时间就会自动的激活一个</SPAN><SPAN
lang=EN-US>Timer1Timer()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件，通过语句</SPAN></P>
<P class=a1><SPAN
lang=EN-US>Form1->ScrollBar1->Position=Form1->MediaPlayer1->Position;</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'">来随时的显示动画播放的进度。</SPAN></P>
<H4><SPAN lang=EN-US>5</SPAN><SPAN
style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">．打开动画文件</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'">在窗体上放置有一个“打开”按钮，它实现诸如打开对话框以及为设置播放文件等功能，所以在它的</SPAN><SPAN
lang=EN-US>Button8Click()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件中添加如下所示的代码：</SPAN></P>
<P class=a1><SPAN lang=EN-US>void __fastcall TForm1::Button8Click(TObject
*Sender)</SPAN></P>
<P class=a1><SPAN lang=EN-US>{</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><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">显示对话框</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>{</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->MediaPlayer1->FileName=Form1->OpenDialog1->FileName;</SPAN></P>
<P class=a1><SPAN lang=EN-US><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'">设置播放文件</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->MediaPlayer1->Open();</SPAN></P>
<P class=a1><SPAN lang=EN-US><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'">打开多媒体播放设备</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->ScrollBar1->Min=0;</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->ScrollBar1->Max=Form1->MediaPlayer1->Length;</SPAN></P>
<P class=a1><SPAN lang=EN-US><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'">初始化滚动条的状态</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->ScrollBar1->Enabled=true;</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>Form1->Button1->Enabled=true;</SPAN></P>
<P class=a1><SPAN lang=EN-US><SPAN style="mso-spacerun: yes">
</SPAN>}</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'">在程序运行的过程中，用鼠标的左键单击“打开”按钮，就会自动的激活组件的</SPAN><SPAN
lang=EN-US>Button8Click()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">事件，程序首先调用</SPAN><SPAN
lang=EN-US>OpenDialog1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件的</SPAN><SPAN
lang=EN-US>Execute()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">方法来显示一个提示用户选择动画文件的对话框，用户在该对话框中可以选择待播放的动画文件，之后程序就会通过语句</SPAN><SPAN
lang=EN-US>Form1->MediaPlayer1->FileName=Form1->OpenDialog1->FileName</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；把用户的选择传递给多媒体播放设备，并且调用组件</SPAN><SPAN
lang=EN-US>MediaPlayer1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN
lang=EN-US>Open()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">方法来打开多媒体播放设备，然后通过一系列语句设置滚动条和其它按钮组件的参数和有效状态。</SPAN></P>
<H4><SPAN lang=EN-US>6</SPAN><SPAN
style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">．播放动画文件</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'">在窗体上的按钮“播放”的作用是播放一个用户选中的动画文件，在</SPAN><SPAN
lang=EN-US>MediaPlayer</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">组件中有一个</SPAN><SPAN
lang=EN-US>Play()</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">方法可以在程序运行的过程中播放一个打开的动画文件，为此，在按钮“播放”的响应过程中添加如下代码：</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->MediaPlayer1->Play();</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'">播放动画</SPAN></P>
<P class=a1><SPAN lang=EN-US>Form1->Button2->Enabled=true;</SPAN></P>
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