[Qgis-developer] run QGIS C++ application "Failed to load"

[xmayyang]

I download code_examples from svn,and build the
"1_hello_world_qgis_style".When I run it, it failed.
fail message:
Failed to load 
Layer is NOT valid
QObject::connect: Cannot connect (null)::repaintRequested() to
QgsMapCanvas::refresh()
QObject::connect: Cannot connect (null)::screenUpdateRequested() to
QgsMapCanvas::updateMap()

I build and install qgis in /usr/local.

This is my cmake configration:
CMAKE_BUILD_TYPE    
CMAKE_INSTALL_PREFIX             /usr/local     
GDAL_CONFIG                      /usr/local/bin/gdal-config      
GDAL_CONFIG_PREFER_PATH          /bin       
GDAL_INCLUDE_DIR                 /usr/local/include        
GDAL_LIBRARY                     /usr/local/lib/libgdal.so         
GEOS_INCLUDE_DIR                 /usr/include/geos          
GEOS_LIBRARY                     /usr/lib/libgeos_c.so           
QGIS_CORE_LIBRARY                /usr/local/lib/libqgis_core.so            
QGIS_GUI_LIBRARY                 /usr/local/lib/libqgis_gui.so             
QGIS_INCLUDE_DIR                 /usr/local/include/qgis              
QGIS_PLUGIN_DIR                  /usr/local/lib/qgis               
QT_QMAKE_EXECUTABLE              /usr/bin/qmake

the code:
#include <qgsapplication.h>
#include <qgsproviderregistry.h>
#include <qgssinglesymbolrenderer.h>
#include <qgsmaplayerregistry.h>
#include <qgsvectorlayer.h>
#include <qgsmapcanvas.h>
#include <QString>
#include <QApplication>
#include <QWidget>

int main(int argc, char ** argv) 
{
  QgsApplication app(argc, argv, true);

  QString myPluginsDir        = "/usr/local/lib/qgis/";
  QString myLayerPath         = "/dev/cpp/shape/bou1_4l";
  QString myLayerBaseName     = "bou1_4l";
  QString myProviderName      = "ogr";
  QgsProviderRegistry::instance(myPluginsDir);
  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");
  }

  QgsMapLayerRegistry::instance()->addMapLayer(mypLayer, TRUE);
  myLayerSet.append(QgsMapCanvasLayer(mypLayer, TRUE));

  QgsMapCanvas * mypMapCanvas = new QgsMapCanvas(0, 0); 
  mypMapCanvas->setExtent(mypLayer->extent());
  mypMapCanvas->enableAntiAliasing(true);
  mypMapCanvas->setCanvasColor(QColor(255, 255, 255));
  mypMapCanvas->freeze(false);
  mypMapCanvas->setLayerSet(myLayerSet);
  mypMapCanvas->setVisible(true);
  mypMapCanvas->refresh();

  return app.exec();

Is there somebody help me?Thank you very much.




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