C++ QgsVectorLayer::providerType方法代码示例

bool QgsGrassEdit::isEditable( QgsMapLayer *layer )
{
  if ( !layer )
    return false;

  QgsDebugMsgLevel( "layer name: " + layer->name(), 3 );

  if ( layer->type() != QgsMapLayer::VectorLayer )
  {
    QgsDebugMsgLevel( "The selected layer is not vector.", 3 );
    return false;
  }

  //TODO dynamic_cast ?
  QgsVectorLayer *vector = ( QgsVectorLayer* )layer;

  QgsDebugMsgLevel( "Vector layer type: " + vector->providerType(), 3 );

  if ( vector->providerType() != "grass" )
  {
    QgsDebugMsgLevel( "The selected layer is not GRASS.", 3 );
    return false;
  }

  return true;
}

QString QgsMapLayer::saveSldStyle( const QString &theURI, bool &theResultFlag )
{
  QString errorMsg;
  QDomDocument myDocument;
  exportSldStyle( myDocument, errorMsg );
  if ( !errorMsg.isNull() )
  {
    theResultFlag = false;
    return errorMsg;
  }
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );

  // check if the uri is a file or ends with .sld,
  // which indicates that it should become one
  QString filename;
  if ( vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = theURI.split( "|" );
    filename = theURIParts[0];
  }
  else if ( vlayer->providerType() == "delimitedtext" )
  {
    filename = QUrl::fromEncoded( theURI.toAscii() ).toLocalFile();
  }
  else
  {
    filename = theURI;
  }

  QFileInfo myFileInfo( filename );
  if ( myFileInfo.exists() || filename.endsWith( ".sld", Qt::CaseInsensitive ) )
  {
    QFileInfo myDirInfo( myFileInfo.path() );  //excludes file name
    if ( !myDirInfo.isWritable() )
    {
      return tr( "The directory containing your dataset needs to be writable!" );
    }

    // now construct the file name for our .sld style file
    QString myFileName = myFileInfo.path() + QDir::separator() + myFileInfo.completeBaseName() + ".sld";

    QFile myFile( myFileName );
    if ( myFile.open( QFile::WriteOnly | QFile::Truncate ) )
    {
      QTextStream myFileStream( &myFile );
      // save as utf-8 with 2 spaces for indents
      myDocument.save( myFileStream, 2 );
      myFile.close();
      theResultFlag = true;
      return tr( "Created default style file as %1" ).arg( myFileName );
    }
  }

  theResultFlag = false;
  return tr( "ERROR: Failed to created SLD style file as %1. Check file permissions and retry." ).arg( filename );
}

// Slot called when the menu item is activated
void QgsGPSPlugin::run()
{
    // find all GPX layers
    std::vector<QgsVectorLayer*> gpxLayers;
    QMap<QString, QgsMapLayer*>::const_iterator iter;
    QgsMapLayerRegistry* registry = QgsMapLayerRegistry::instance();
    QMap<QString, QgsMapLayer*> layers = registry->mapLayers();
    for ( iter = layers.constBegin();
            iter != layers.constEnd(); ++iter )
    {
        if ( iter.value()->type() == QgsMapLayer::VectorLayer )
        {
            QgsVectorLayer* vLayer = qobject_cast<QgsVectorLayer *>( iter.value() );
            if ( vLayer->providerType() == QLatin1String( "gpx" ) )
                gpxLayers.push_back( vLayer );
        }
    }

    QgsGPSPluginGui *myPluginGui =
        new QgsGPSPluginGui( mImporters, mDevices, gpxLayers, mQGisInterface->mainWindow(),
                             QgisGui::ModalDialogFlags );
    myPluginGui->setAttribute( Qt::WA_DeleteOnClose );
    //listen for when the layer has been made so we can draw it
    connect( myPluginGui, SIGNAL( drawVectorLayer( QString, QString, QString ) ),
             this, SLOT( drawVectorLayer( QString, QString, QString ) ) );
    connect( myPluginGui, SIGNAL( loadGPXFile( QString, bool, bool, bool ) ),
             this, SLOT( loadGPXFile( QString, bool, bool, bool ) ) );
    connect( myPluginGui, SIGNAL( importGPSFile( QString, QgsBabelFormat*, bool,
                                  bool, bool, QString, QString ) ),
             this, SLOT( importGPSFile( QString, QgsBabelFormat*, bool, bool,
                                        bool, QString, QString ) ) );
    connect( myPluginGui, SIGNAL( convertGPSFile( QString, int,
                                  QString, QString ) ),
             this, SLOT( convertGPSFile( QString, int,
                                         QString, QString ) ) );
    connect( myPluginGui, SIGNAL( downloadFromGPS( QString, QString, bool, bool,
                                  bool, QString, QString ) ),
             this, SLOT( downloadFromGPS( QString, QString, bool, bool, bool,
                                          QString, QString ) ) );
    connect( myPluginGui, SIGNAL( uploadToGPS( QgsVectorLayer*, QString, QString ) ),
             this, SLOT( uploadToGPS( QgsVectorLayer*, QString, QString ) ) );
    connect( this, SIGNAL( closeGui() ), myPluginGui, SLOT( close() ) );

    myPluginGui->show();
}

// Slot called when the menu item is activated
void QgsGPSPlugin::run()
{
  // find all GPX layers
  std::vector<QgsVectorLayer *> gpxLayers;
  QMap<QString, QgsMapLayer *>::const_iterator iter;
  QMap<QString, QgsMapLayer *> layers = QgsProject::instance()->mapLayers();
  for ( iter = layers.constBegin();
        iter != layers.constEnd(); ++iter )
  {
    if ( iter.value()->type() == QgsMapLayer::VectorLayer )
    {
      QgsVectorLayer *vLayer = qobject_cast<QgsVectorLayer *>( iter.value() );
      if ( vLayer->providerType() == QLatin1String( "gpx" ) )
        gpxLayers.push_back( vLayer );
    }
  }

  QgsGPSPluginGui *myPluginGui =
    new QgsGPSPluginGui( mImporters, mDevices, gpxLayers, mQGisInterface->mainWindow(),
                         QgsGuiUtils::ModalDialogFlags );
  myPluginGui->setAttribute( Qt::WA_DeleteOnClose );
  //listen for when the layer has been made so we can draw it
  connect( myPluginGui, &QgsGPSPluginGui::drawVectorLayer,
           this, &QgsGPSPlugin::drawVectorLayer );
  connect( myPluginGui, &QgsGPSPluginGui::loadGPXFile,
           this, &QgsGPSPlugin::loadGPXFile );
  connect( myPluginGui, &QgsGPSPluginGui::importGPSFile,
           this, &QgsGPSPlugin::importGPSFile );
  connect( myPluginGui, &QgsGPSPluginGui::convertGPSFile,
           this, &QgsGPSPlugin::convertGPSFile );
  connect( myPluginGui, &QgsGPSPluginGui::downloadFromGPS,
           this, &QgsGPSPlugin::downloadFromGPS );
  connect( myPluginGui, &QgsGPSPluginGui::uploadToGPS,
           this, &QgsGPSPlugin::uploadToGPS );
  connect( this, &QgsGPSPlugin::closeGui, myPluginGui, &QWidget::close );

  myPluginGui->show();
}

bool QgsMapLayer::writeLayerXML( QDomElement& layerElement, QDomDocument& document )
{
  // use scale dependent visibility flag
  layerElement.setAttribute( "hasScaleBasedVisibilityFlag", hasScaleBasedVisibility() ? 1 : 0 );
  layerElement.setAttribute( "minimumScale", QString::number( minimumScale() ) );
  layerElement.setAttribute( "maximumScale", QString::number( maximumScale() ) );

  // ID
  QDomElement layerId = document.createElement( "id" );
  QDomText layerIdText = document.createTextNode( id() );
  layerId.appendChild( layerIdText );

  layerElement.appendChild( layerId );

  // data source
  QDomElement dataSource = document.createElement( "datasource" );

  QString src = source();

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  // TODO: what about postgres, mysql and others, they should not go through writePath()
  if ( vlayer && vlayer->providerType() == "spatialite" )
  {
    QgsDataSourceURI uri( src );
    QString database = QgsProject::instance()->writePath( uri.database() );
    uri.setConnection( uri.host(), uri.port(), database, uri.username(), uri.password() );
    src = uri.uri();
  }
  else if ( vlayer && vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = src.split( "|" );
    theURIParts[0] = QgsProject::instance()->writePath( theURIParts[0] );
    src = theURIParts.join( "|" );
  }
  else if ( vlayer && vlayer->providerType() == "delimitedtext" )
  {
    QUrl urlSource = QUrl::fromEncoded( src.toAscii() );
    QUrl urlDest = QUrl::fromLocalFile( QgsProject::instance()->writePath( urlSource.toLocalFile() ) );
    urlDest.setQueryItems( urlSource.queryItems() );
    src = QString::fromAscii( urlDest.toEncoded() );
  }
  else
  {
    src = QgsProject::instance()->writePath( src );
  }

  QDomText dataSourceText = document.createTextNode( src );
  dataSource.appendChild( dataSourceText );

  layerElement.appendChild( dataSource );


  // layer name
  QDomElement layerName = document.createElement( "layername" );
  QDomText layerNameText = document.createTextNode( originalName() );
  layerName.appendChild( layerNameText );

  // layer title
  QDomElement layerTitle = document.createElement( "title" ) ;
  QDomText layerTitleText = document.createTextNode( title() );
  layerTitle.appendChild( layerTitleText );

  // layer abstract
  QDomElement layerAbstract = document.createElement( "abstract" );
  QDomText layerAbstractText = document.createTextNode( abstract() );
  layerAbstract.appendChild( layerAbstractText );

  layerElement.appendChild( layerName );
  layerElement.appendChild( layerTitle );
  layerElement.appendChild( layerAbstract );

  // layer keyword list
  QStringList keywordStringList = keywordList().split( "," );
  if ( keywordStringList.size() > 0 )
  {
    QDomElement layerKeywordList = document.createElement( "keywordList" );
    for ( int i = 0; i < keywordStringList.size(); ++i )
    {
      QDomElement layerKeywordValue = document.createElement( "value" );
      QDomText layerKeywordText = document.createTextNode( keywordStringList.at( i ).trimmed() );
      layerKeywordValue.appendChild( layerKeywordText );
      layerKeywordList.appendChild( layerKeywordValue );
    }
    layerElement.appendChild( layerKeywordList );
  }

  // layer metadataUrl
  QString aDataUrl = dataUrl();
  if ( !aDataUrl.isEmpty() )
  {
    QDomElement layerDataUrl = document.createElement( "dataUrl" ) ;
    QDomText layerDataUrlText = document.createTextNode( aDataUrl );
    layerDataUrl.appendChild( layerDataUrlText );
    layerDataUrl.setAttribute( "format", dataUrlFormat() );
    layerElement.appendChild( layerDataUrl );
  }

  // layer attribution
  QString aAttribution = attribution();
  if ( !aAttribution.isEmpty() )
//.........这里部分代码省略.........

QString QgsMapLayer::saveNamedStyle( const QString &theURI, bool &theResultFlag )
{
  QString myErrorMessage;
  QDomDocument myDocument;
  exportNamedStyle( myDocument, myErrorMessage );

  // check if the uri is a file or ends with .qml,
  // which indicates that it should become one
  // everything else goes to the database
  QString filename;

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  if ( vlayer && vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = theURI.split( "|" );
    filename = theURIParts[0];
  }
  else if ( vlayer && vlayer->providerType() == "delimitedtext" )
  {
    filename = QUrl::fromEncoded( theURI.toAscii() ).toLocalFile();
  }
  else
  {
    filename = theURI;
  }

  QFileInfo myFileInfo( filename );
  if ( myFileInfo.exists() || filename.endsWith( ".qml", Qt::CaseInsensitive ) )
  {
    QFileInfo myDirInfo( myFileInfo.path() );  //excludes file name
    if ( !myDirInfo.isWritable() )
    {
      return tr( "The directory containing your dataset needs to be writable!" );
    }

    // now construct the file name for our .qml style file
    QString myFileName = myFileInfo.path() + QDir::separator() + myFileInfo.completeBaseName() + ".qml";

    QFile myFile( myFileName );
    if ( myFile.open( QFile::WriteOnly | QFile::Truncate ) )
    {
      QTextStream myFileStream( &myFile );
      // save as utf-8 with 2 spaces for indents
      myDocument.save( myFileStream, 2 );
      myFile.close();
      theResultFlag = true;
      return tr( "Created default style file as %1" ).arg( myFileName );
    }
    else
    {
      theResultFlag = false;
      return tr( "ERROR: Failed to created default style file as %1. Check file permissions and retry." ).arg( myFileName );
    }
  }
  else
  {
    QString qml = myDocument.toString();

    // read from database
    sqlite3 *myDatabase;
    sqlite3_stmt *myPreparedStatement;
    const char *myTail;
    int myResult;

    myResult = sqlite3_open( QDir( QgsApplication::qgisSettingsDirPath() ).absoluteFilePath( "qgis.qmldb" ).toUtf8().data(), &myDatabase );
    if ( myResult != SQLITE_OK )
    {
      return tr( "User database could not be opened." );
    }

    QByteArray param0 = theURI.toUtf8();
    QByteArray param1 = qml.toUtf8();

    QString mySql = "create table if not exists tbl_styles(style varchar primary key,qml varchar)";
    myResult = sqlite3_prepare( myDatabase, mySql.toUtf8().data(), mySql.toUtf8().length(), &myPreparedStatement, &myTail );
    if ( myResult == SQLITE_OK )
    {
      if ( sqlite3_step( myPreparedStatement ) != SQLITE_DONE )
      {
        sqlite3_finalize( myPreparedStatement );
        sqlite3_close( myDatabase );
        theResultFlag = false;
        return tr( "The style table could not be created." );
      }
    }

    sqlite3_finalize( myPreparedStatement );

    mySql = "insert into tbl_styles(style,qml) values (?,?)";
    myResult = sqlite3_prepare( myDatabase, mySql.toUtf8().data(), mySql.toUtf8().length(), &myPreparedStatement, &myTail );
    if ( myResult == SQLITE_OK )
    {
      if ( sqlite3_bind_text( myPreparedStatement, 1, param0.data(), param0.length(), SQLITE_STATIC ) == SQLITE_OK &&
           sqlite3_bind_text( myPreparedStatement, 2, param1.data(), param1.length(), SQLITE_STATIC ) == SQLITE_OK &&
           sqlite3_step( myPreparedStatement ) == SQLITE_DONE )
      {
        theResultFlag = true;
        myErrorMessage = tr( "The style %1 was saved to database" ).arg( theURI );
      }
    }
//.........这里部分代码省略.........

QString QgsMapLayer::saveSldStyle( const QString theURI, bool & theResultFlag )
{
  QDomDocument myDocument = QDomDocument();

  QDomNode header = myDocument.createProcessingInstruction( "xml", "version=\"1.0\" encoding=\"UTF-8\"" );
  myDocument.appendChild( header );

  // Create the root element
  QDomElement root = myDocument.createElementNS( "http://www.opengis.net/sld", "StyledLayerDescriptor" );
  root.setAttribute( "version", "1.1.0" );
  root.setAttribute( "xsi:schemaLocation", "http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd" );
  root.setAttribute( "xmlns:ogc", "http://www.opengis.net/ogc" );
  root.setAttribute( "xmlns:se", "http://www.opengis.net/se" );
  root.setAttribute( "xmlns:xlink", "http://www.w3.org/1999/xlink" );
  root.setAttribute( "xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance" );
  myDocument.appendChild( root );

  // Create the NamedLayer element
  QDomElement namedLayerNode = myDocument.createElement( "NamedLayer" );
  root.appendChild( namedLayerNode );

  QString errorMsg;
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  if ( !vlayer )
  {
    theResultFlag = false;
    return tr( "Could not save symbology because:\n%1" ).arg( "Non-vector layers not supported yet" );
  }

  if ( !vlayer->writeSld( namedLayerNode, myDocument, errorMsg ) )
  {
    theResultFlag = false;
    return tr( "Could not save symbology because:\n%1" ).arg( errorMsg );
  }

  // check if the uri is a file or ends with .sld,
  // which indicates that it should become one
  QString filename;
  if ( vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = theURI.split( "|" );
    filename = theURIParts[0];
  }
  else if ( vlayer->providerType() == "delimitedtext" )
  {
    filename = QUrl::fromEncoded( theURI.toAscii() ).toLocalFile();
  }
  else
  {
    filename = theURI;
  }

  QFileInfo myFileInfo( filename );
  if ( myFileInfo.exists() || filename.endsWith( ".sld", Qt::CaseInsensitive ) )
  {
    QFileInfo myDirInfo( myFileInfo.path() );  //excludes file name
    if ( !myDirInfo.isWritable() )
    {
      return tr( "The directory containing your dataset needs to be writable!" );
    }

    // now construct the file name for our .sld style file
    QString myFileName = myFileInfo.path() + QDir::separator() + myFileInfo.completeBaseName() + ".sld";

    QFile myFile( myFileName );
    if ( myFile.open( QFile::WriteOnly | QFile::Truncate ) )
    {
      QTextStream myFileStream( &myFile );
      // save as utf-8 with 2 spaces for indents
      myDocument.save( myFileStream, 2 );
      myFile.close();
      theResultFlag = true;
      return tr( "Created default style file as %1" ).arg( myFileName );
    }
  }

  theResultFlag = false;
  return tr( "ERROR: Failed to created SLD style file as %1. Check file permissions and retry." ).arg( filename );
}

QString QgsMapLayer::saveNamedStyle( const QString theURI, bool & theResultFlag )
{
  QString myErrorMessage;

  QDomImplementation DomImplementation;
  QDomDocumentType documentType =
    DomImplementation.createDocumentType(
      "qgis", "http://mrcc.com/qgis.dtd", "SYSTEM" );
  QDomDocument myDocument( documentType );
  QDomElement myRootNode = myDocument.createElement( "qgis" );
  myRootNode.setAttribute( "version", QString( "%1" ).arg( QGis::QGIS_VERSION ) );
  myDocument.appendChild( myRootNode );

  // use scale dependent visibility flag
  myRootNode.setAttribute( "hasScaleBasedVisibilityFlag", hasScaleBasedVisibility() ? 1 : 0 );
  myRootNode.setAttribute( "minimumScale", minimumScale() );
  myRootNode.setAttribute( "maximumScale", maximumScale() );

  // <transparencyLevelInt>
  QDomElement transparencyLevelIntElement = myDocument.createElement( "transparencyLevelInt" );
  QDomText    transparencyLevelIntText    = myDocument.createTextNode( QString::number( getTransparency() ) );
  transparencyLevelIntElement.appendChild( transparencyLevelIntText );
  myRootNode.appendChild( transparencyLevelIntElement );
  // now append layer node to map layer node

  QString errorMsg;
  if ( !writeSymbology( myRootNode, myDocument, errorMsg ) )
  {
    return tr( "Could not save symbology because:\n%1" ).arg( errorMsg );
  }

  // check if the uri is a file or ends with .qml,
  // which indicates that it should become one
  // everything else goes to the database
  QString filename;

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  if ( vlayer && vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = theURI.split( "|" );
    filename = theURIParts[0];
  }
  else if ( vlayer && vlayer->providerType() == "delimitedtext" )
  {
    filename = QUrl::fromEncoded( theURI.toAscii() ).toLocalFile();
  }
  else
  {
    filename = theURI;
  }

  QFileInfo myFileInfo( filename );
  if ( myFileInfo.exists() || filename.endsWith( ".qml", Qt::CaseInsensitive ) )
  {
    QFileInfo myDirInfo( myFileInfo.path() );  //excludes file name
    if ( !myDirInfo.isWritable() )
    {
      return tr( "The directory containing your dataset needs to be writable!" );
    }

    // now construct the file name for our .qml style file
    QString myFileName = myFileInfo.path() + QDir::separator() + myFileInfo.completeBaseName() + ".qml";

    QFile myFile( myFileName );
    if ( myFile.open( QFile::WriteOnly | QFile::Truncate ) )
    {
      QTextStream myFileStream( &myFile );
      // save as utf-8 with 2 spaces for indents
      myDocument.save( myFileStream, 2 );
      myFile.close();
      theResultFlag = true;
      return tr( "Created default style file as %1" ).arg( myFileName );
    }
    else
    {
      theResultFlag = false;
      return tr( "ERROR: Failed to created default style file as %1. Check file permissions and retry." ).arg( myFileName );
    }
  }
  else
  {
    QString qml = myDocument.toString();

    // read from database
    sqlite3 *myDatabase;
    sqlite3_stmt *myPreparedStatement;
    const char *myTail;
    int myResult;

    myResult = sqlite3_open( QDir( QgsApplication::qgisSettingsDirPath() ).absoluteFilePath( "qgis.qmldb" ).toUtf8().data(), &myDatabase );
    if ( myResult != SQLITE_OK )
    {
      return tr( "User database could not be opened." );
    }

    QByteArray param0 = theURI.toUtf8();
    QByteArray param1 = qml.toUtf8();

    QString mySql = "create table if not exists tbl_styles(style varchar primary key,qml varchar)";
    myResult = sqlite3_prepare( myDatabase, mySql.toUtf8().data(), mySql.toUtf8().length(), &myPreparedStatement, &myTail );
//.........这里部分代码省略.........

bool QgsMapLayer::writeXML( QDomNode & layer_node, QDomDocument & document )
{
  // general layer metadata
  QDomElement maplayer = document.createElement( "maplayer" );

  // use scale dependent visibility flag
  maplayer.setAttribute( "hasScaleBasedVisibilityFlag", hasScaleBasedVisibility() ? 1 : 0 );
  maplayer.setAttribute( "minimumScale", minimumScale() );
  maplayer.setAttribute( "maximumScale", maximumScale() );

  // ID
  QDomElement layerId = document.createElement( "id" );
  QDomText layerIdText = document.createTextNode( id() );
  layerId.appendChild( layerIdText );

  maplayer.appendChild( layerId );

  // data source
  QDomElement dataSource = document.createElement( "datasource" );

  QString src = source();

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  if ( vlayer && vlayer->providerType() == "spatialite" )
  {
    QgsDataSourceURI uri( src );
    QString database = QgsProject::instance()->writePath( uri.database() );
    uri.setConnection( uri.host(), uri.port(), database, uri.username(), uri.password() );
    src = uri.uri();
  }
  else if ( vlayer && vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = src.split( "|" );
    theURIParts[0] = QgsProject::instance()->writePath( theURIParts[0] );
    src = theURIParts.join( "|" );
  }
  else if ( vlayer && vlayer->providerType() == "delimitedtext" )
  {
    QUrl urlSource = QUrl::fromEncoded( src.toAscii() );
    QUrl urlDest = QUrl::fromLocalFile( QgsProject::instance()->writePath( urlSource.toLocalFile() ) );
    urlDest.setQueryItems( urlSource.queryItems() );
    src = QString::fromAscii( urlDest.toEncoded() );
  }
  else
  {
    src = QgsProject::instance()->writePath( src );
  }

  QDomText dataSourceText = document.createTextNode( src );
  dataSource.appendChild( dataSourceText );

  maplayer.appendChild( dataSource );


  // layer name
  QDomElement layerName = document.createElement( "layername" );
  QDomText layerNameText = document.createTextNode( name() );
  layerName.appendChild( layerNameText );

  // layer title
  QDomElement layerTitle = document.createElement( "title" ) ;
  QDomText layerTitleText = document.createTextNode( title() );
  layerTitle.appendChild( layerTitleText );

  // layer abstract
  QDomElement layerAbstract = document.createElement( "abstract" );
  QDomText layerAbstractText = document.createTextNode( abstract() );
  layerAbstract.appendChild( layerAbstractText );

  maplayer.appendChild( layerName );
  maplayer.appendChild( layerTitle );
  maplayer.appendChild( layerAbstract );

  // timestamp if supported
  if ( timestamp() > QDateTime() )
  {
    QDomElement stamp = document.createElement( "timestamp" );
    QDomText stampText = document.createTextNode( timestamp().toString( Qt::ISODate ) );
    stamp.appendChild( stampText );
    maplayer.appendChild( stamp );
  }

  maplayer.appendChild( layerName );

  // zorder
  // This is no longer stored in the project file. It is superfluous since the layers
  // are written and read in the proper order.

  // spatial reference system id
  QDomElement mySrsElement = document.createElement( "srs" );
  mCRS->writeXML( mySrsElement, document );
  maplayer.appendChild( mySrsElement );

  // <transparencyLevelInt>
  QDomElement transparencyLevelIntElement = document.createElement( "transparencyLevelInt" );
  QDomText    transparencyLevelIntText    = document.createTextNode( QString::number( getTransparency() ) );
  transparencyLevelIntElement.appendChild( transparencyLevelIntText );
  maplayer.appendChild( transparencyLevelIntElement );
  // now append layer node to map layer node

//.........这里部分代码省略.........

bool QgsMapLayer::writeLayerXML( QDomElement& layerElement, QDomDocument& document, const QString& relativeBasePath )
{
  // use scale dependent visibility flag
  layerElement.setAttribute( "hasScaleBasedVisibilityFlag", hasScaleBasedVisibility() ? 1 : 0 );
  layerElement.setAttribute( "minimumScale", QString::number( minimumScale() ) );
  layerElement.setAttribute( "maximumScale", QString::number( maximumScale() ) );

  // ID
  QDomElement layerId = document.createElement( "id" );
  QDomText layerIdText = document.createTextNode( id() );
  layerId.appendChild( layerIdText );

  layerElement.appendChild( layerId );

  // data source
  QDomElement dataSource = document.createElement( "datasource" );

  QString src = source();

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( this );
  // TODO: what about postgres, mysql and others, they should not go through writePath()
  if ( vlayer && vlayer->providerType() == "spatialite" )
  {
    QgsDataSourceURI uri( src );
    QString database = QgsProject::instance()->writePath( uri.database(), relativeBasePath );
    uri.setConnection( uri.host(), uri.port(), database, uri.username(), uri.password() );
    src = uri.uri();
  }
  else if ( vlayer && vlayer->providerType() == "ogr" )
  {
    QStringList theURIParts = src.split( "|" );
    theURIParts[0] = QgsProject::instance()->writePath( theURIParts[0], relativeBasePath );
    src = theURIParts.join( "|" );
  }
  else if ( vlayer && vlayer->providerType() == "gpx" )
  {
    QStringList theURIParts = src.split( "?" );
    theURIParts[0] = QgsProject::instance()->writePath( theURIParts[0], relativeBasePath );
    src = theURIParts.join( "?" );
  }
  else if ( vlayer && vlayer->providerType() == "delimitedtext" )
  {
    QUrl urlSource = QUrl::fromEncoded( src.toAscii() );
    QUrl urlDest = QUrl::fromLocalFile( QgsProject::instance()->writePath( urlSource.toLocalFile(), relativeBasePath ) );
    urlDest.setQueryItems( urlSource.queryItems() );
    src = QString::fromAscii( urlDest.toEncoded() );
  }
  else
  {
    bool handled = false;

    if ( !vlayer )
    {
      QgsRasterLayer *rlayer = qobject_cast<QgsRasterLayer *>( this );
      // Update path for subdataset
      if ( rlayer && rlayer->providerType() == "gdal" )
      {
        if ( src.startsWith( "NETCDF:" ) )
        {
          // NETCDF:filename:variable
          // filename can be quoted with " as it can contain colons
          QRegExp r( "NETCDF:(.+):([^:]+)" );
          if ( r.exactMatch( src ) )
          {
            QString filename = r.cap( 1 );
            if ( filename.startsWith( '"' ) && filename.endsWith( '"' ) )
              filename = filename.mid( 1, filename.length() - 2 );
            src = "NETCDF:\"" + QgsProject::instance()->writePath( filename, relativeBasePath ) + "\":" + r.cap( 2 );
            handled = true;
          }
        }
        else if ( src.startsWith( "HDF4_SDS:" ) )
        {
          // HDF4_SDS:subdataset_type:file_name:subdataset_index
          // filename can be quoted with " as it can contain colons
          QRegExp r( "HDF4_SDS:([^:]+):(.+):([^:]+)" );
          if ( r.exactMatch( src ) )
          {
            QString filename = r.cap( 2 );
            if ( filename.startsWith( '"' ) && filename.endsWith( '"' ) )
              filename = filename.mid( 1, filename.length() - 2 );
            src = "HDF4_SDS:" + r.cap( 1 ) + ":\"" + QgsProject::instance()->writePath( filename, relativeBasePath ) + "\":" + r.cap( 3 );
            handled = true;
          }
        }
        else if ( src.startsWith( "HDF5:" ) )
        {
          // HDF5:file_name:subdataset
          // filename can be quoted with " as it can contain colons
          QRegExp r( "HDF5:(.+):([^:]+)" );
          if ( r.exactMatch( src ) )
          {
            QString filename = r.cap( 1 );
            if ( filename.startsWith( '"' ) && filename.endsWith( '"' ) )
              filename = filename.mid( 1, filename.length() - 2 );
            src = "HDF5:\"" + QgsProject::instance()->writePath( filename, relativeBasePath ) + "\":" + r.cap( 2 );
            handled = true;
          }
        }
        else if ( src.contains( QRegExp( "^(NITF_IM|RADARSAT_2_CALIB):" ) ) )
//.........这里部分代码省略.........