QGis 2.4 C ++ helloWorld

In a project I am working on (C / C ++ / Qt application) we are trying to integrate QGis (latest version preferably 2.4 for now). But there is very little information on the internet on how to use the QGis C ++ API.

To begin with, I wanted to write a simple code example (read a shapefile and render it in a window). I found sample code for QGis 1.8, but it doesn't work with QGis 2.4 as the API has changed since then. Then I tried to edit it to work with QGis 2.4 but failed. Here is the source code:

#include <QtCore/QString>
#include <QtGui/QApplication>

#include <qgsapplication.h>
#include <qgsproviderregistry.h>
#include <qgssinglesymbolrenderer.h>
#include <qgsmaplayerregistry.h>
#include <qgsvectorlayer.h>
#include <qgsmapcanvas.h>

#include <iostream>

int main(int argc, char** argv)
{
  // Creation of the Qt GIS application
  QgsApplication app(argc, argv, true);

  // Hard coded paths
  QString myPluginsDir        = "/usr/lib64/qgis";
  QString myLayerPath         = "./HelloWorld/GUI/data/helloQGIS.shp";
  QString myLayerBaseName     = "helloQGIS";
  QString myProviderName      = "ogr";

  // Instantiate Provider Registry
  QgsProviderRegistry::instance(myPluginsDir);

  // Create a maplayer instance
  QgsVectorLayer* mypLayer = new QgsVectorLayer(myLayerPath, myLayerBaseName, myProviderName);
  QgsSingleSymbolRenderer* mypRenderer = new QgsSingleSymbolRenderer(mypLayer->geometryType());
  QList <QgsMapCanvasLayer> myLayerSet;
  mypLayer->setRenderer(mypRenderer);
  if (mypLayer->isValid())
  {
    qDebug("Layer is valid");
  }
  else
  {
    qDebug("Layer is NOT valid");
  }

  // Add the Vector Layer to the Layer Registry
  QList<QgsMapLayer*> theMapLayers;
  theMapLayers.append(mypLayer);
  QgsMapLayerRegistry::instance()->addMapLayers(theMapLayers, TRUE);

  // Add the Layer to the Layer Set
  myLayerSet.append(QgsMapCanvasLayer(mypLayer, TRUE));

  // Create the Map Canvas
  QgsMapCanvas * mypMapCanvas = new QgsMapCanvas(0, 0);
  mypMapCanvas->setExtent(mypLayer->extent());
  mypMapCanvas->enableAntiAliasing(true);
  mypMapCanvas->setCanvasColor(QColor(255, 255, 255));
  mypMapCanvas->freeze(false);
  // Set the Map Canvas Layer Set
  mypMapCanvas->setLayerSet(myLayerSet);
  mypMapCanvas->setVisible(true);
  mypMapCanvas->refresh();
  mypMapCanvas->show();

  // Start the Application Event Loop
  return app.exec();
}

      

        
        
        
      

    

I tried many different ways to change this code to work with QGis 2.4 but failed. The only source of information I have used is the official doc API .

I said myself that maybe someone has already done this and / or has some other example of using QGis 2.4. Since GIS is a new domain for me, I have some difficulties to understand how the API is supposed to work. I appreciate any help, thanks.