C++ QgsVectorDataProvider::addAttributes方法代码示例

QgsVectorLayer* RgExportDlg::mapLayer() const
{
  QgsVectorLayer* myLayer = NULL;
  QString layerId = mcbLayers->itemData( mcbLayers->currentIndex() ).toString();

  if ( layerId == "-1" )
  {
    // create a temporary layer
    myLayer = new QgsVectorLayer( QString( "LineString?crs=epsg:4326&memoryid=%1" ).arg( QUuid::createUuid().toString() ), "shortest path", "memory" );

    QgsVectorDataProvider *prov = myLayer->dataProvider();
    if ( prov == NULL )
      return NULL;

    QList<QgsField> attrList;
    attrList.append( QgsField( "length", QVariant::Double, "", 20, 8 ) );
    attrList.append( QgsField( "time", QVariant::Double, "", 20, 8 ) );
    prov->addAttributes( attrList );
    myLayer->updateFields();
    QList<QgsMapLayer *> myList;
    myList << myLayer;
    QgsMapLayerRegistry::instance()->addMapLayers( myList );
  }
  else
  {
    // return selected layer
    myLayer = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( layerId ) );
  }

  return myLayer;
} // QgsVectorLayer* RgExportDlg::vectorLayer() const

QgsVectorLayer* RgExportDlg::mapLayer() const
{
  QgsVectorLayer* myLayer = NULL;
  QString layerId = mcbLayers->itemData( mcbLayers->currentIndex() ).toString();

  if ( layerId == QString( "-1" ) )
  {
    // create a temporary layer
    myLayer = new QgsVectorLayer( "LineString", "shortest path", "memory" );

    QgsVectorDataProvider *prov = myLayer->dataProvider();
    if ( prov == NULL )
      return NULL;

    QList<QgsField> attrList;
    attrList.append( QgsField( "one", QVariant::Int ) );
    prov->addAttributes( attrList );
    QList<QgsMapLayer *> myList;
    myList << myLayer;
    QgsMapLayerRegistry::instance()->addMapLayers( myList );

  }
  else
  {
    // retrun selected layer
    myLayer = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( layerId ) );
  }

  return myLayer;
} // QgsVectorLayer* RgExportDlg::vectorLayer() const

//.........这里部分代码省略.........
  {
    rangeFieldName = getUniqueFieldName( mAttributePrefix + "range", newFieldList );
    QgsField rangeField( rangeFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
    newFieldList.push_back( rangeField );
  }
  QString minorityFieldName;
  if ( mStatistics & QgsZonalStatistics::Minority )
  {
    minorityFieldName = getUniqueFieldName( mAttributePrefix + "minority", newFieldList );
    QgsField minorityField( minorityFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
    newFieldList.push_back( minorityField );
  }
  QString majorityFieldName;
  if ( mStatistics & QgsZonalStatistics::Majority )
  {
    majorityFieldName = getUniqueFieldName( mAttributePrefix + "majority", newFieldList );
    QgsField majField( majorityFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
    newFieldList.push_back( majField );
  }
  QString varietyFieldName;
  if ( mStatistics & QgsZonalStatistics::Variety )
  {
    varietyFieldName = getUniqueFieldName( mAttributePrefix + "variety", newFieldList );
    QgsField varietyField( varietyFieldName, QVariant::Int, QStringLiteral( "int" ) );
    newFieldList.push_back( varietyField );
  }
  QString varianceFieldName;
  if ( mStatistics & QgsZonalStatistics::Variance )
  {
    varianceFieldName = getUniqueFieldName( mAttributePrefix + "variance", newFieldList );
    QgsField varianceField( varianceFieldName, QVariant::Double, QStringLiteral( "double precision" ) );
    newFieldList.push_back( varianceField );
  }
  vectorProvider->addAttributes( newFieldList );

  //index of the new fields
  int countIndex = mStatistics & QgsZonalStatistics::Count ? vectorProvider->fieldNameIndex( countFieldName ) : -1;
  int sumIndex = mStatistics & QgsZonalStatistics::Sum ? vectorProvider->fieldNameIndex( sumFieldName ) : -1;
  int meanIndex = mStatistics & QgsZonalStatistics::Mean ? vectorProvider->fieldNameIndex( meanFieldName ) : -1;
  int medianIndex = mStatistics & QgsZonalStatistics::Median ? vectorProvider->fieldNameIndex( medianFieldName ) : -1;
  int stdevIndex = mStatistics & QgsZonalStatistics::StDev ? vectorProvider->fieldNameIndex( stdevFieldName ) : -1;
  int minIndex = mStatistics & QgsZonalStatistics::Min ? vectorProvider->fieldNameIndex( minFieldName ) : -1;
  int maxIndex = mStatistics & QgsZonalStatistics::Max ? vectorProvider->fieldNameIndex( maxFieldName ) : -1;
  int rangeIndex = mStatistics & QgsZonalStatistics::Range ? vectorProvider->fieldNameIndex( rangeFieldName ) : -1;
  int minorityIndex = mStatistics & QgsZonalStatistics::Minority ? vectorProvider->fieldNameIndex( minorityFieldName ) : -1;
  int majorityIndex = mStatistics & QgsZonalStatistics::Majority ? vectorProvider->fieldNameIndex( majorityFieldName ) : -1;
  int varietyIndex = mStatistics & QgsZonalStatistics::Variety ? vectorProvider->fieldNameIndex( varietyFieldName ) : -1;
  int varianceIndex = mStatistics & QgsZonalStatistics::Variance ? vectorProvider->fieldNameIndex( varianceFieldName ) : -1;

  if ( ( mStatistics & QgsZonalStatistics::Count && countIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Sum && sumIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Mean && meanIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Median && medianIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::StDev && stdevIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Min && minIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Max && maxIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Range && rangeIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Minority && minorityIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Majority && majorityIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Variety && varietyIndex == -1 )
       || ( mStatistics & QgsZonalStatistics::Variance && varianceIndex == -1 )
     )
  {
    //failed to create a required field
    return 8;
  }

int QgsZonalStatistics::calculateStatistics( QProgressDialog* p )
{
  if ( !mPolygonLayer || mPolygonLayer->geometryType() != QGis::Polygon )
  {
    return 1;
  }

  QgsVectorDataProvider* vectorProvider = mPolygonLayer->dataProvider();
  if ( !vectorProvider )
  {
    return 2;
  }

  //open the raster layer and the raster band
  GDALAllRegister();
  GDALDatasetH inputDataset = GDALOpen( mRasterFilePath.toLocal8Bit().data(), GA_ReadOnly );
  if ( inputDataset == NULL )
  {
    return 3;
  }

  if ( GDALGetRasterCount( inputDataset ) < ( mRasterBand - 1 ) )
  {
    GDALClose( inputDataset );
    return 4;
  }

  GDALRasterBandH rasterBand = GDALGetRasterBand( inputDataset, mRasterBand );
  if ( rasterBand == NULL )
  {
    GDALClose( inputDataset );
    return 5;
  }
  mInputNodataValue = GDALGetRasterNoDataValue( rasterBand, NULL );

  //get geometry info about raster layer
  int nCellsX = GDALGetRasterXSize( inputDataset );
  int nCellsY = GDALGetRasterYSize( inputDataset );
  double geoTransform[6];
  if ( GDALGetGeoTransform( inputDataset, geoTransform ) != CE_None )
  {
    GDALClose( inputDataset );
    return 6;
  }
  double cellsizeX = geoTransform[1];
  if ( cellsizeX < 0 )
  {
    cellsizeX = -cellsizeX;
  }
  double cellsizeY = geoTransform[5];
  if ( cellsizeY < 0 )
  {
    cellsizeY = -cellsizeY;
  }
  QgsRectangle rasterBBox( geoTransform[0], geoTransform[3] - ( nCellsY * cellsizeY ), geoTransform[0] + ( nCellsX * cellsizeX ), geoTransform[3] );

  //add the new count, sum, mean fields to the provider
  QList<QgsField> newFieldList;
  QgsField countField( mAttributePrefix + "count", QVariant::Double );
  QgsField sumField( mAttributePrefix + "sum", QVariant::Double );
  QgsField meanField( mAttributePrefix + "mean", QVariant::Double );
  newFieldList.push_back( countField );
  newFieldList.push_back( sumField );
  newFieldList.push_back( meanField );
  if ( !vectorProvider->addAttributes( newFieldList ) )
  {
    return 7;
  }

  //index of the new fields
  int countIndex = vectorProvider->fieldNameIndex( mAttributePrefix + "count" );
  int sumIndex = vectorProvider->fieldNameIndex( mAttributePrefix + "sum" );
  int meanIndex = vectorProvider->fieldNameIndex( mAttributePrefix + "mean" );

  if ( countIndex == -1 || sumIndex == -1 || meanIndex == -1 )
  {
    return 8;
  }

  //progress dialog
  long featureCount = vectorProvider->featureCount();
  if ( p )
  {
    p->setMaximum( featureCount );
  }


  //iterate over each polygon
  vectorProvider->select( QgsAttributeList(), QgsRectangle(), true, false );
  vectorProvider->rewind();
  QgsFeature f;
  double count = 0;
  double sum = 0;
  double mean = 0;
  int featureCounter = 0;

  while ( vectorProvider->nextFeature( f ) )
  {
    qWarning( "%d", featureCounter );
    if ( p )
//.........这里部分代码省略.........

//.........这里部分代码省略.........
  {
    maxFieldName = getUniqueFieldName( mAttributePrefix + "max" );
    QgsField maxField( maxFieldName, QVariant::Double, "double precision" );
    newFieldList.push_back( maxField );
  }
  QString rangeFieldName;
  if ( mStatistics & QgsZonalStatistics::Range )
  {
    rangeFieldName = getUniqueFieldName( mAttributePrefix + "range" );
    QgsField rangeField( rangeFieldName, QVariant::Double, "double precision" );
    newFieldList.push_back( rangeField );
  }
  QString minorityFieldName;
  if ( mStatistics & QgsZonalStatistics::Minority )
  {
    minorityFieldName = getUniqueFieldName( mAttributePrefix + "minority" );
    QgsField minorityField( minorityFieldName, QVariant::Double, "double precision" );
    newFieldList.push_back( minorityField );
  }
  QString majorityFieldName;
  if ( mStatistics & QgsZonalStatistics::Majority )
  {
    majorityFieldName = getUniqueFieldName( mAttributePrefix + "majority" );
    QgsField majField( majorityFieldName, QVariant::Double, "double precision" );
    newFieldList.push_back( majField );
  }
  QString varietyFieldName;
  if ( mStatistics & QgsZonalStatistics::Variety )
  {
    varietyFieldName = getUniqueFieldName( mAttributePrefix + "variety" );
    QgsField varietyField( varietyFieldName, QVariant::Int, "int" );
    newFieldList.push_back( varietyField );
  }
  vectorProvider->addAttributes( newFieldList );

  //index of the new fields
  int countIndex = mStatistics & QgsZonalStatistics::Count ? vectorProvider->fieldNameIndex( countFieldName ) : -1;
  int sumIndex = mStatistics & QgsZonalStatistics::Sum ? vectorProvider->fieldNameIndex( sumFieldName ) : -1;
  int meanIndex = mStatistics & QgsZonalStatistics::Mean ? vectorProvider->fieldNameIndex( meanFieldName ) : -1;
  int medianIndex = mStatistics & QgsZonalStatistics::Median ? vectorProvider->fieldNameIndex( medianFieldName ) : -1;
  int stdevIndex = mStatistics & QgsZonalStatistics::StDev ? vectorProvider->fieldNameIndex( stdevFieldName ) : -1;
  int minIndex = mStatistics & QgsZonalStatistics::Min ? vectorProvider->fieldNameIndex( minFieldName ) : -1;
  int maxIndex = mStatistics & QgsZonalStatistics::Max ? vectorProvider->fieldNameIndex( maxFieldName ) : -1;
  int rangeIndex = mStatistics & QgsZonalStatistics::Range ? vectorProvider->fieldNameIndex( rangeFieldName ) : -1;
  int minorityIndex = mStatistics & QgsZonalStatistics::Minority ? vectorProvider->fieldNameIndex( minorityFieldName ) : -1;
  int majorityIndex = mStatistics & QgsZonalStatistics::Majority ? vectorProvider->fieldNameIndex( majorityFieldName ) : -1;
  int varietyIndex = mStatistics & QgsZonalStatistics::Variety ? vectorProvider->fieldNameIndex( varietyFieldName ) : -1;

  if (( mStatistics & QgsZonalStatistics::Count && countIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Sum && sumIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Mean && meanIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Median && medianIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::StDev && stdevIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Min && minIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Max && maxIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Range && rangeIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Minority && minorityIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Majority && majorityIndex == -1 )
      || ( mStatistics & QgsZonalStatistics::Variety && varietyIndex == -1 )
     )
  {
    //failed to create a required field
    return 8;
  }

  //progress dialog

bool QgsVectorLayerEditBuffer::commitChanges( QStringList& commitErrors )
{
  QgsVectorDataProvider* provider = L->dataProvider();
  commitErrors.clear();

  int cap = provider->capabilities();
  bool success = true;

  QgsFields oldFields = L->pendingFields();

  //
  // delete attributes
  //
  bool attributesChanged = false;
  if ( !mDeletedAttributeIds.isEmpty() )
  {
    if (( cap & QgsVectorDataProvider::DeleteAttributes ) && provider->deleteAttributes( mDeletedAttributeIds.toSet() ) )
    {
      commitErrors << tr( "SUCCESS: %n attribute(s) deleted.", "deleted attributes count", mDeletedAttributeIds.size() );

      emit committedAttributesDeleted( L->id(), mDeletedAttributeIds );

      mDeletedAttributeIds.clear();
      attributesChanged = true;
    }
    else
    {
      commitErrors << tr( "ERROR: %n attribute(s) not deleted.", "not deleted attributes count", mDeletedAttributeIds.size() );
      success = false;
    }
  }

  //
  // add attributes
  //
  if ( !mAddedAttributes.isEmpty() )
  {
    if (( cap & QgsVectorDataProvider::AddAttributes ) && provider->addAttributes( mAddedAttributes ) )
    {
      commitErrors << tr( "SUCCESS: %n attribute(s) added.", "added attributes count", mAddedAttributes.size() );

      emit committedAttributesAdded( L->id(), mAddedAttributes );

      mAddedAttributes.clear();
      attributesChanged = true;
    }
    else
    {
      commitErrors << tr( "ERROR: %n new attribute(s) not added", "not added attributes count", mAddedAttributes.size() );
      success = false;
    }
  }

  //
  // check that addition/removal went as expected
  //
  bool attributeChangesOk = true;
  if ( attributesChanged )
  {
    L->updateFields();
    QgsFields newFields = L->pendingFields();

    if ( oldFields.count() != newFields.count() )
    {
      commitErrors << tr( "ERROR: the count of fields is incorrect after addition/removal of fields!" );
      attributeChangesOk = false;   // don't try attribute updates - they'll fail.
    }

    for ( int i = 0; i < oldFields.count(); ++i )
    {
      const QgsField& oldField = oldFields[i];
      const QgsField& newField = newFields[i];
      if ( attributeChangesOk && oldField != newField )
      {
        commitErrors << tr( "ERROR: field with index %1 is not the same!" ).arg( i );
        attributeChangesOk = false;   // don't try attribute updates - they'll fail.
      }
    }
  }

  if ( attributeChangesOk )
  {
    //
    // change attributes
    //
    if ( !mChangedAttributeValues.isEmpty() )
    {
      if (( cap & QgsVectorDataProvider::ChangeAttributeValues ) && provider->changeAttributeValues( mChangedAttributeValues ) )
      {
        commitErrors << tr( "SUCCESS: %n attribute value(s) changed.", "changed attribute values count", mChangedAttributeValues.size() );

        emit committedAttributeValuesChanges( L->id(), mChangedAttributeValues );

        mChangedAttributeValues.clear();
      }
      else
      {
        commitErrors << tr( "ERROR: %n attribute value change(s) not applied.", "not changed attribute values count", mChangedAttributeValues.size() );
        success = false;
      }
//.........这里部分代码省略.........