QT读取XML文件，结构

Question

我正在使用QXmlStreamReader处理XML文件。读取循环是很直截了当：

if (!file.open(QFile::ReadOnly | QFile::Text)) { 
     strErrors.append(mcszConfigFile); 
     strErrors.append("\n\nDoes not exists!\n\n"); 
    } 
    xmlrdr.setDevice(&file); 
    xmlrdr.readNext(); 
    blnRootFound = false; 
    while(!xmlrdr.atEnd()) { 
     /* [Edit] This shouldn't be here! if (xmlrdr.isStartElement()) */{ 
      QXmlStreamAttributes attrs = xmlrdr.attributes(); 
      QStringRef srfNodeName = xmlrdr.name(); 
      bool blnEndElement = xmlrdr.isEndElement(); 
      bool blnStartElement = xmlrdr.isStartElement(); 
      bool blnInvalid = true; 

      if (attrs.length() > 0) { 
       QString strID, strNodeName = srfNodeName.toString(); 

       if (attrs.hasAttribute(mcszXMLattrID) == false) { 
        strErrors.append("Node: "); 
        strErrors.append(qPrintable(srfNodeName.toString())); 
        strErrors.append("Has no id!\n"); 
        break; 
       } 
       strID = attrs.value(mcszXMLattrID).toString(); 

       if (strNodeName.compare(mcszXMLnodeRoot) == 0) { 
        blnRootFound = true; 
        blnInvalid = false; 
        mstrRootID = strID; 
       } else if (strNodeName.compare(mcszXMLnodeButton) == 0 
         || strNodeName.compare(mcszXMLnodeButtonBar) == 0 
         || strNodeName.compare(mcszXMLnodeOption) == 0) { 
        blnInvalid = false; 
       } else if (strNodeName.compare(mcszXMLnodeControl) == 0) { 
        for(int t=0; mcpszValidControlTypes[t]!=NULL; t++) { 
         if (strID.compare(mcpszValidControlTypes[t]) == 0) { 
          blnInvalid = false; 
          break; 
         } 
        } 
       } 
       if (strID.length() > 0 && blnInvalid == false) { 
        clsXMLnode objNode = clsXMLnode(strNodeName, &attrs, this);      
        msmapNodes.insert(std::pair<QString, clsXMLnode>(strID, objNode)); 
        msmapAreas.insert(std::pair<QString, QRect>(strID, objNode.rctGetGeom())); 
        if (blnStartElement == true) { 

        } 
       } 
      } 
     } 
     xmlrdr.readNext(); 
    } 
    if (file.isOpen() ) { 
     file.close(); 
    } 

，我读取XML：

<?xml version="1.0" encoding="utf-8"?> 
    <!-- 
    Node:   gui 
    Attrbuttes: left, right, top and bottom defines the pixel white space to allow 
        from the edge of the display 
      language, should be set to the appropriate country code, an XML file named using 
      the country code must exist, e.g. 44.xml 
    //--> 
    <gui id="root" bottom="0" left="0" right="0" top="24" language="44"> 
     <control id="trainstrip" 
      x="(center:SCREEN) - (25%:SCREEN_WIDTH)" y="(top:SCREEN)" height="40px" width="(50%:SCREEN_WIDTH)"/> 
     <control id="elevationstrip" 
       x="(left:trainstrip) - 56px" y="(top:trainstrip) + (height:trainstrip) + 24px" width="56px" height="{75%:SCREEN_HEIGHT}"/> 
     <control id="lofmimics" 
      color_arc="#ffaaaaaa" 
       color_axis="#fff0000" 
       color_bg="#ffaaaaaa" 
       color_needle="#ffffff00" 
       color_min_limit="#ffbbbb00" 
       color_max_limit="#ffcc00cc" 
       color_port="#ff00aa00" 
       color_starboard="'#ffaa0000" 
       elevation_height="275px" 
      elevation_mech_max="85" 
       elevation_mech_min="-10" 
       elevation_max="85" 
       elevation_margin_left="64px" 
       elevation_margin_bottom="64px" 
       elevation_min="-10" 
       elevation_pensize_limit="3" 
       elevation_pensize_reading="3" 
       elevation_width="[elevation_height]" 
       elevation_x="0px" 
      elevation_y="0px" 
       training_mech_starboard="170" 
       training_mech_port="-170" 
       training_pensize_port="5" 
       training_pensize_starboard="5" 
       training_pensize_limit="3" 
       training_pensize_reading="3" 
       training_starboard="150" 
       training_port="-150" 
       training_width="(left:elevationstrip)" 
       training_height="([training_width])" 
      training_x="([elevation_x])" 
      training_y="([elevation_height])" 
       x="(left:SCREEN)" 
      width="([x]:elevationstrip)" 
      height="([training_height]) + ([elevation_height])" 
       y="(bottom:SCREEN) - ([height])"/> 
     <buttonbar id="modes"  
      height="50%" 
      width="100px" 
      x="(RIGHT:SCREEN) - ([width])" 
      y="(TOP:SCREEN)" 
      title="MODE" 
      color_bg="#ffaaaaaa" 
      border="inset:#ffcccccc,#ff333333" 
      button_height="24px" 
       button_width="80px" 
      vertical_space="4px"> 
     <button id="btnsetup" color_bg="#ff3399ff" x="0px" y="{top:modes}"> 
      <option value="0" text="operate<"/> 
      <option value="1" text="setup"/> 
      <option value="2" text="install"/> 
      <option value="3" text="startup"/> 
      <option value="4" text="shutdown"/> 
     </button>  
     </buttonbar> 
    </gui> 

我遇到的问题是标志blnEndElement和blnStartElement似乎没有准确地反映正确的在读取文件时，blnEndElement始终为false，blnStartElement始终为true。

我想要做的是构建节点/元素层次结构，同时读取和处理XML。

Answer 1

我遇到的问题是标志blnEndElement和blnStartElement似乎没有准确地反映正确的状态时，读取文件，blnEndElement始终是假的，blnStartElement始终为true。

如果我正确理解您的问题，您会得到本地变量blnEndElement和blnStartElement的错误值。我在下面强调如果条件是这种行为的原因：

while(!xmlrdr.atEnd()) { 
     if (xmlrdr.isStartElement()) { 
     //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
      QXmlStreamAttributes attrs = xmlrdr.attributes(); 
      QStringRef srfNodeName = xmlrdr.name(); 
      bool blnEndElement = xmlrdr.isEndElement(); 
      bool blnStartElement = xmlrdr.isStartElement(); 
      // ^^^^^^^^^^ Same as above if condition, ALWAYS be TRUE, if control reaches this line. 

      bool blnInvalid = true; 

只有当条件满足时才执行内部代码否则代码将被跳过。