magnitudetree-4-3.html

构建定制的树型视图

        bottommainout.src="../i/main.gif";
        topsectionover.src="../i/h-section.gif";
        topsectionout.src="../i/section.gif";      
        bottomsectionover.src="../i/h-section.gif";
        bottomsectionout.src="../i/section.gif";      
        topfeedbackover.src="../i/h-feedback.gif";
        topfeedbackout.src="../i/feedback.gif";
        bottomfeedbackover.src="../i/h-feedback.gif";
        bottomfeedbackout.src="../i/feedback.gif";
        toppreviousover.src="../i/h-previous.gif";
        toppreviousout.src="../i/previous.gif";
        bottompreviousover.src="../i/h-previous.gif";
        bottompreviousout.src="../i/previous.gif";
        topnextover.src="../i/h-next.gif";
        topnextout.src="../i/next.gif";
        bottomnextover.src="../i/h-next.gif";
        bottomnextout.src="../i/next.gif";
        topnextsectionout.src="../i/nextsection.gif";
        topnextsectionover.src="../i/h-nextsection.gif";
        bottomnextsectionout.src="../i/nextsection.gif";
        bottomnextsectionover.src="../i/h-nextsection.gif";
      }
      function iOut(image)
      {
        if (browser=="N3")document[image].src=eval(image + "out.src");
      }
      function iOver(image)
      {
        if (browser=="N3")document[image].src=eval(image + "over.src");
      }
     // --></script><!-- <script src="../i/emailfriend.js" language="javascript"></script> --><a href="#navskip"><img border="0" alt="跳至主要内容" src="../i/c.gif"></a>
        <table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr bgcolor="#006699">
<td><table width="300" border="0" cellspacing="0" cellpadding="0">
<tr bgcolor="#006699">
<td width="150"><img src="../i/mast_logo.gif" alt="IBM" width="150" height="25"/></td>
<td width="150" background="../i/mgradient.gif"><font size="2" color="#99ccff" face="宋体"><b>中国</b></font><br /> <img src="../i/c.gif" width="150" height="1" alt=""/></td>
</tr></table> 
</td>
<td align="left"><table width="300" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="100"><a href="/cgi-bin/click.p?url=http://www.ibm.com/cn/shop"><img border="0" src="../i/shopibm.gif" width="100" height="25" alt="购物"/></a></td>
<td width="100"><a href="/cgi-bin/click.p?url=http://www.ibm.com/cn/support"><img border="0" src="../i/support_chs.gif" width="100" height="25" alt="技术支持"/></a></td>
<td width="100"><a href="/cgi-bin/click.p?url=http://www.ibm.com/cn/support/product"><img border="0" src="../i/downloads_chs.gif" width="100" height="25" alt="免费下载"/></a></td></tr></table>
</td></tr></table>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr bgcolor="#000000">
<td><table width="600" border="0" cellspacing="0" cellpadding="0">
<tr><td bgcolor="#006699" width="150"><img src="../i/mast_lnav_sp.gif" width="150" height="21" alt=""/></td>
<td colspan="4" bgcolor="#000000"><table border="0" cellspacing="0" cellpadding="0" height="21">
<tr>
<td height="21" bgcolor="#000000" width="79" align="center"><a class="nav" style="color: #ffffff;" href="/cgi-bin/click.p?url=http://www.ibm.com/cn"><font size="2" color="#ffffff" face="宋体"><b>IBM 主页</b></font></a></td>
<td bgcolor="#959595" width="1"><img src="../i/c.gif" width="1" height="1" alt=""/></td>
<td height="21" bgcolor="#000000" width="74" align="center"><a class="nav" style="color: #ffffff;" href=/cgi-bin/click.p?url=http://www.ibm.com/cn/products><font size="2" color="#ffffff" face="宋体"><b>产品</b></font></a></td>
<td bgcolor="#959595" width="1"><img src="../i/c.gif" width="1" height="1" alt=""/></td>
<td height="21" bgcolor="#000000" width="81" align="center"><a class="nav" style="color: #ffffff;" href="/cgi-bin/click.p?url=http://www.ibm.com/cn/services"><font size="2" color="#ffffff" face="宋体"><b>咨询</b></font></a></td><td bgcolor="#959595" width="1"><img src="../i/c.gif" width="1" height="1" alt=""/></td>
<td height="21" bgcolor="#000000" width="81" align="center"><a class="nav" style="color: #ffffff;" href="/cgi-bin/click.p?url=http://www.ibm.com/cn/industry"><font size="2" color="#ffffff" face="宋体"><b>行业</b></font></a></td>
<td bgcolor="#959595" width="1"><img src="../i/c.gif" width="1" height="1" alt=""/></td>
<td height="21" bgcolor="#000000" width="57" align="center"><a class="nav" style="color: #ffffff;" href="/cgi-bin/click.p?url=http://www.ibm.com/cn/news"><font size="2" color="#ffffff" face="宋体"><b>新闻</b>
                                                </font></a></td>
<td bgcolor="#959595" width="1"><img src="../i/c.gif" width="1" height="1" alt=""/></td>
<td height="21" bgcolor="#000000" width="78" align="center"><a class="nav" style="color: #ffffff;" href="/cgi-bin/click.p?url=http://www.ibm.com/cn/ibm"><font size="2" color="#ffffff" face="宋体"><b>关于 IBM</b>
                                                </font></a></td></tr></table></td></tr></table></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD width="150" height="1" bgcolor="#ffffff"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR><TR><TD width="150" height="3" bgcolor="#cc6633"><IMG alt="" height="3" width="150" src="../i/c.gif"></TD></TR><TR><TD width="150" height="1" bgcolor="#333333"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR><TR><TD width="150" height="1" bgcolor="#000000"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR></TABLE><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr><td><font face="Verdana, sans-serif" size="-1"><a href="/cgi-bin/click.p?url=http://www.ibm.com/cn">IBM</a> : <a
href="/developerWorks/">developerWorks 中国</a> : <a
href="/developerWorks/java/">Java</a> : <a
href="/developerWorks/education/java/">教学 - 在线课程</a></font><br x="7"><img src="imagemaster/masthead.jpg" alt="构建定制的树型视图"></td><td width="*" valign="bottom" align="right"><a border="0" href="../MagnitudeTree.zip"><img alt="下载教程 zip 文件" border="0" src="../i/icon-zip.gif"></a><a href=../MagnitudeTree_eng/index.html target=_blank><img alt="英文原文" border="0" src="../i/icon-source.gif"></a></td></tr><tr><td height="2" colspan="2"><img height="2" width="1" src="../i/c.gif"></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR><TR><TD background="../i/sw-gold.gif"><a border="0" href="index.html" onMouseOver="iOver('topmain'); iOver('bottommain'); self.status=mainblurb; return true;" onMouseOut="iOut('topmain'); iOut('bottommain'); self.status=''; return true;"><img alt="主菜单" border="0" src="../i/main.gif" name="topmain"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topsection'); iOver('bottomsection'); self.status=sectionblurb; return true;" onMouseOut="iOut('topsection'); iOut('bottomsection'); self.status=''; return true;" href="index4.html"><img alt="章节菜单" border="0" src="../i/section.gif" name="topsection"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topfeedback'); iOver('bottomfeedback'); self.status=feedbackblurb; return true;" onMouseOut="iOut('topfeedback'); iOut('bottomfeedback'); self.status=''; return true;" href="MagnitudeTree-7-4.html"><img alt="提交反馈意见" border="0" src="../i/feedback.gif" name="topfeedback"></a></TD><TD width="100%" background="../i/sw-gold.gif"><img src="../i/c.gif"></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topprevious'); iOver('bottomprevious'); self.status=previousblurb; return true;" onMouseOut="iOut('topprevious'); iOut('bottomprevious'); self.status=''; return true;" href="MagnitudeTree-4-2.html"><img alt="上一屏" border="0" src="../i/previous.gif" name="topprevious"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topnext'); iOver('bottomnext'); self.status=nextblurb; return true;" onMouseOut="iOut('topnext'); iOut('bottomnext'); self.status=''; return true;" href="MagnitudeTree-4-4.html"><img alt="下一屏" border="0" src="../i/next.gif" name="topnext"></a></TD></TR></TABLE><table bgcolor="ffffff" cellspacing="0" cellpadding="2" border="0" height="400" width="100%"><tr valign="bottom"><a name="navskip"></a><td height="25" colspan="4"><img border="0" height="25" width="562" src="imagemaster/titlebar4.jpg" alt="4. 定制绘制"></td></tr><tr><td bgcolor="ffffff" width="15">&nbsp;</td><td bgcolor="ffffff" width="12">&nbsp;</td><td valign="top" align="left" bgcolor="ffffff" width="*"><p><br x="7"><table cellspacing="0" cellpadding="0" border="0"><tr><td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>DefaultTreeCellRenderer 类</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr>    第 3 页（共 7 页）</nobr></font></td></tr></table><br x="7"><br x="7"></p><font size="2" face="Verdana, Arial, Helvetica"><p>
DefaultTreeCellRenderer 有双重目的。首先，它实现了 TreeCellRenderer，因此提供了 <code style="font-family: Courier New, Courier, monospace; font-size:
12">getTreeCellRendererComponent()</code> 方法。其次，它还扩展了
Swing JLabel 类，并使用继承的 JLabel 行为来帮助提供树节点绘制能力。JLabel
类支持图标与邻近文本一起显示，但不支持树节点的“已展开／已折叠”状态的概念，或显示选择或焦点重点。
          </p><p>
可以向 DefaultTreeCellRenderer 提供三个图标：其中两个用于表示可以包含子女的节点的“展开／折叠”状态，第三个表示叶节点。还可以提供用于选择和焦点状态的颜色。
          </p><p>
DefaultTreeCellRenderer 从 <code style="font-family: Courier New, Courier, monospace; font-size:
12">getTreeCellRendererComponent()</code> 方法中返回它自己。在此之前，它使用参数信息来确定应显示哪个图标和文本，并将这些信息传递给其
JLabel 超类以便 JLabel 可以使用它们。DefaultTreeCellRenderer 还覆盖了 JLabel <code
style="font-family: Courier New, Courier, monospace; font-size:
12">paint()</code> 方法，这样它可以在调用 JLabel 绘制方法之前绘制选择和焦点重点。
          </p><p>
            <script>
document.writeln('<a href=""')
document.writeln('  onMouseOver="document.images[\'TreeRender\'].src=\'images/TreeRenderA.gif\'"')
document.writeln('  onMouseOut="document.images[\'TreeRender\'].src=\'images/TreeRender.gif\'">')
document.writeln('  <img src="images/TreeRender.gif" alt="节点状态和重点"')
document.writeln('          name="TreeRender" border="0">')
document.writeln('  </img>')
document.writeln('</a>')
            </script>
            <br x="7">             图 4.1. 节点状态和重点（将鼠标置于图上以产生动画效果）           </p><p>
图 4.1 说明了 Windows 资源管理器中的一个简单树。它使用文件夹隐喻和文件节点的特有图标，来显示容器节点的“展开”和“折叠”状态。它还显示了个别节点上的选择和焦点重点。
          </p><p>
DefaultTreeCellRenderer 提供了丰富的显示功能，但它不显示数量信息。要使树型视图可以显示数量信息，需要创建一个定制的树单元绘制程序。下一页中将说明这一点。
          </p><br x="7"></font></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD background="../i/sw-gold.gif"><a border="0" href="index.html" onMouseOver="iOver('topmain'); iOver('bottommain'); self.status=mainblurb; return true;" onMouseOut="iOut('topmain'); iOut('bottommain'); self.status=''; return true;"><img alt="主菜单" border="0" src="../i/main.gif" name="bottommain"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topsection'); iOver('bottomsection'); self.status=sectionblurb; return true;" onMouseOut="iOut('topsection'); iOut('bottomsection'); self.status=''; return true;" href="index4.html"><img alt="章节菜单" border="0" src="../i/section.gif" name="bottomsection"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topfeedback'); iOver('bottomfeedback'); self.status=feedbackblurb; return true;" onMouseOut="iOut('topfeedback'); iOut('bottomfeedback'); self.status=''; return true;" href="MagnitudeTree-7-4.html"><img alt="提交反馈意见" border="0" src="../i/feedback.gif" name="bottomfeedback"></a></TD><TD width="100%" background="../i/sw-gold.gif"><img src="../i/c.gif"></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topprevious'); iOver('bottomprevious'); self.status=previousblurb; return true;" onMouseOut="iOut('topprevious'); iOut('bottomprevious'); self.status=''; return true;" href="MagnitudeTree-4-2.html"><img alt="上一屏" border="0" src="../i/previous.gif" name="bottomprevious"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topnext'); iOver('bottomnext'); self.status=nextblurb; return true;" onMouseOut="iOut('topnext'); iOut('bottomnext'); self.status=''; return true;" href="MagnitudeTree-4-4.html"><img alt="下一屏" border="0" src="../i/next.gif" name="bottomnext"></a></TD></TR><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR></TABLE><TABLE cellpadding="0" cellspacing="0" border="0"><TR><TD width="182"><TABLE cellpadding="0" cellspacing="0" border="0" width="182">
            <TR bgcolor="#000000"><TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/privacy/"><font face="Arial, Verdana" size="2">隐私</font></a></TD>
            <TD width="1" bgcolor="#959595"><img alt="" border="0" height="20" width="1" src="../i/c.gif"></TD>
            <TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/legal/"><font face="Arial, Verdana" size="2">法律</font></a></TD>
            <TD width="1" bgcolor="#959595"><img alt="" border="0" height="20" width="1" src="../i/c.gif"></TD>
            <TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/contact/"><font face="Arial, Verdana" size="2">联系</font></a></TD>
            <TD width="1" bgcolor="#959595"><img alt="" border="0" height="21" width="1" src="../i/c.gif"></TD></TR><TR bgcolor="#ffffff"><TD><img alt="" border="0" height="1" width="1" src="../i/c.gif"></TD></TR></TABLE></TD><TD width="100%"><TABLE cellpadding="0" cellspacing="0" border="0" width="100%"><TR height="21" bgcolor="#000000"><TD><img alt="" border="0" height="21" width="1" src="../i/c.gif"></TD></TR><TR bgcolor="#ffffff"><TD><img alt="" border="0" height="1" width="1" src="../i/c.gif"></TD></TR></TABLE></TD></TR></TABLE></body></html>