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

/**
* Selection routine called by the mouse release event
* @param thePoint = QgsPoint representing the x, y coordinates of the mouse release event
*/
void eVisEventIdTool::select( QgsPoint thePoint )
{

  if ( 0 == mCanvas )
    return;

  QgsVectorLayer* myLayer = ( QgsVectorLayer* )mCanvas->currentLayer( );

  // create the search rectangle. this was modeled after the QgsMapIdentifyTool in core QGIS application
  double searchWidth = mCanvas->extent( ).width( ) * (( double )QGis::DEFAULT_IDENTIFY_RADIUS / 100.0 );

  QgsRectangle myRectangle;
  myRectangle.setXMinimum( thePoint.x( ) - searchWidth );
  myRectangle.setXMaximum( thePoint.x( ) + searchWidth );
  myRectangle.setYMinimum( thePoint.y( ) - searchWidth );
  myRectangle.setYMaximum( thePoint.y( ) + searchWidth );

  //Transform rectange to map coordinates
  myRectangle = toLayerCoordinates( myLayer, myRectangle );

  //Rather than add to the current selection, clear all selected features
  myLayer->removeSelection( false );
  //select features
  QgsFeatureIterator fit = myLayer->getFeatures( QgsFeatureRequest().setFilterRect( myRectangle ).setFlags( QgsFeatureRequest::ExactIntersect ).setSubsetOfAttributes( QgsAttributeList() ) );

  QgsFeature f;
  QgsFeatureIds newSelectedFeatures;
  while ( fit.nextFeature( f ) )
  {
    newSelectedFeatures.insert( f.id() );
  }

  myLayer->setSelectedFeatures( newSelectedFeatures );

  //Launch a new event browser to view selected features
  mBrowser = new eVisGenericEventBrowserGui( mCanvas, mCanvas, NULL );
  mBrowser->setAttribute( Qt::WA_DeleteOnClose );
}

//.........这里部分代码省略.........
  if ( canvas->mapSettings().hasCrsTransformEnabled() )
  {
    try
    {
      QgsCoordinateTransform ct( canvas->mapSettings().destinationCrs(), vlayer->crs() );
      selectGeomTrans.transform( ct );
    }
    catch ( QgsCsException &cse )
    {
      Q_UNUSED( cse );
      // catch exception for 'invalid' point and leave existing selection unchanged
      QgsLogger::warning( "Caught CRS exception " + QString( __FILE__ ) + ": " + QString::number( __LINE__ ) );
      QgisApp::instance()->messageBar()->pushMessage(
        QObject::tr( "CRS Exception" ),
        QObject::tr( "Selection extends beyond layer's coordinate system" ),
        QgsMessageBar::WARNING,
        QgisApp::instance()->messageTimeout() );
      return;
    }
  }

  QApplication::setOverrideCursor( Qt::WaitCursor );

  QgsDebugMsg( "Selection layer: " + vlayer->name() );
  QgsDebugMsg( "Selection polygon: " + selectGeomTrans.exportToWkt() );
  QgsDebugMsg( "doContains: " + QString( doContains ? "T" : "F" ) );
  QgsDebugMsg( "doDifference: " + QString( doDifference ? "T" : "F" ) );

  QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest().setFilterRect( selectGeomTrans.boundingBox() ).setFlags( QgsFeatureRequest::ExactIntersect ).setSubsetOfAttributes( QgsAttributeList() ) );

  QgsFeatureIds newSelectedFeatures;
  QgsFeature f;
  QgsFeatureId closestFeatureId = 0;
  bool foundSingleFeature = false;
  double closestFeatureDist = std::numeric_limits<double>::max();
  while ( fit.nextFeature( f ) )
  {
    QgsGeometry* g = f.geometry();
    if ( doContains )
    {
      if ( !selectGeomTrans.contains( g ) )
        continue;
    }
    else
    {
      if ( !selectGeomTrans.intersects( g ) )
        continue;
    }
    if ( singleSelect )
    {
      foundSingleFeature = true;
      double distance = g->distance( selectGeomTrans );
      if ( distance <= closestFeatureDist )
      {
        closestFeatureDist = distance;
        closestFeatureId = f.id();
      }
    }
    else
    {
      newSelectedFeatures.insert( f.id() );
    }
  }
  if ( singleSelect && foundSingleFeature )
  {
    newSelectedFeatures.insert( closestFeatureId );
  }

  QgsDebugMsg( "Number of new selected features: " + QString::number( newSelectedFeatures.size() ) );

  if ( doDifference )
  {
    QgsFeatureIds layerSelectedFeatures = vlayer->selectedFeaturesIds();

    QgsFeatureIds selectedFeatures;
    QgsFeatureIds deselectedFeatures;

    QgsFeatureIds::const_iterator i = newSelectedFeatures.constEnd();
    while ( i != newSelectedFeatures.constBegin() )
    {
      --i;
      if ( layerSelectedFeatures.contains( *i ) )
      {
        deselectedFeatures.insert( *i );
      }
      else
      {
        selectedFeatures.insert( *i );
      }
    }

    vlayer->modifySelection( selectedFeatures, deselectedFeatures );
  }
  else
  {
    vlayer->setSelectedFeatures( newSelectedFeatures );
  }

  QApplication::restoreOverrideCursor();
}

void QgsGeometrySnapperDialog::run()
{
  /** Get layers **/
  QgsVectorLayer* layer = getInputLayer();
  QgsVectorLayer* referenceLayer = getReferenceLayer();
  if ( layer == 0 || referenceLayer == 0 )
  {
    return;
  }

  if ( ui.radioButtonOutputNew->isChecked() &&
       ( layer->dataProvider()->dataSourceUri().startsWith( ui.lineEditOutput->text() ) ||
         referenceLayer->dataProvider()->dataSourceUri().startsWith( ui.lineEditOutput->text() ) ) )
  {
    QMessageBox::critical( this, tr( "Invalid Output Layer" ), tr( "The chosen output layer is the same as an input layer." ) );
    return;
  }

  bool selectedOnly = ui.checkBoxInputSelectedOnly->isChecked();

  /** Duplicate if necessary **/
  if ( ui.radioButtonOutputNew->isChecked() )
  {
    QString filename = ui.lineEditOutput->text();

    // Remove existing layer with same uri
    QStringList toRemove;
    foreach ( QgsMapLayer* maplayer, QgsMapLayerRegistry::instance()->mapLayers() )
    {
      if ( dynamic_cast<QgsVectorLayer*>( maplayer ) &&
           static_cast<QgsVectorLayer*>( maplayer )->dataProvider()->dataSourceUri().startsWith( filename ) )
      {
        toRemove.append( maplayer->id() );
      }
    }
    if ( !toRemove.isEmpty() )
    {
      QgsMapLayerRegistry::instance()->removeMapLayers( toRemove );
    }

    QString errMsg;
    QgsVectorFileWriter::WriterError err =  QgsVectorFileWriter::writeAsVectorFormat( layer, filename, layer->dataProvider()->encoding(), &layer->crs(), mOutputDriverName, selectedOnly, &errMsg );
    if ( err != QgsVectorFileWriter::NoError )
    {
      QMessageBox::critical( this, tr( "Layer Creation Failed" ), tr( "Failed to create the output layer: %1" ).arg( errMsg ) );
      return;
    }
    QgsVectorLayer* newlayer = new QgsVectorLayer( filename, QFileInfo( filename ).completeBaseName(), "ogr" );

    if ( selectedOnly )
    {
      QgsFeature feature;

      // Get features to select (only selected features were written up to this point)
      QgsFeatureIds selectedFeatures = newlayer->allFeatureIds();

      // Write non-selected feature ids
      QgsFeatureList features;
      QgsFeatureIterator it = layer->getFeatures();
      while ( it.nextFeature( feature ) )
      {
        if ( !layer->selectedFeaturesIds().contains( feature.id() ) )
        {
          features.append( feature );
        }
      }
      newlayer->dataProvider()->addFeatures( features );

      // Set selected features
      newlayer->setSelectedFeatures( selectedFeatures );
    }
    layer = newlayer;
  }