Quantum GIS API Documentation  1.8
src/core/qgsmaplayerregistry.cpp
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00001 /***************************************************************************
00002  *  QgsMapLayerRegistry.cpp  -  Singleton class for tracking mMapLayers.
00003  *                         -------------------
00004  * begin                : Sun June 02 2004
00005  * copyright            : (C) 2004 by Tim Sutton
00006  * email                : tim@linfiniti.com
00007  ***************************************************************************/
00008 
00009 /***************************************************************************
00010  *                                                                         *
00011  *   This program is free software; you can redistribute it and/or modify  *
00012  *   it under the terms of the GNU General Public License as published by  *
00013  *   the Free Software Foundation; either version 2 of the License, or     *
00014  *   (at your option) any later version.                                   *
00015  *                                                                         *
00016  ***************************************************************************/
00017 
00018 #include "qgsmaplayerregistry.h"
00019 #include "qgsmaplayer.h"
00020 #include "qgslogger.h"
00021 
00022 //
00023 // Static calls to enforce singleton behaviour
00024 //
00025 QgsMapLayerRegistry *QgsMapLayerRegistry::mInstance = 0;
00026 QgsMapLayerRegistry *QgsMapLayerRegistry::instance()
00027 {
00028   if ( mInstance == 0 )
00029   {
00030     mInstance = new QgsMapLayerRegistry();
00031   }
00032   return mInstance;
00033 }
00034 
00035 //
00036 // Main class begins now...
00037 //
00038 
00039 QgsMapLayerRegistry::QgsMapLayerRegistry( QObject *parent ) : QObject( parent )
00040 {
00041   // constructor does nothing
00042 }
00043 
00044 QgsMapLayerRegistry::~QgsMapLayerRegistry()
00045 {
00046   removeAllMapLayers();
00047 }
00048 
00049 // get the layer count (number of registered layers)
00050 int QgsMapLayerRegistry::count()
00051 {
00052   return mMapLayers.size();
00053 }
00054 
00055 QgsMapLayer * QgsMapLayerRegistry::mapLayer( QString theLayerId )
00056 {
00057   return mMapLayers.value( theLayerId );
00058 }
00059 
00060 //introduced in 1.8
00061 QList<QgsMapLayer *> QgsMapLayerRegistry::addMapLayers(
00062   QList<QgsMapLayer *> theMapLayers,
00063   bool theEmitSignal )
00064 {
00065   QList<QgsMapLayer *> myResultList;
00066   for ( int i = 0; i < theMapLayers.size(); ++i )
00067   {
00068     QgsMapLayer * myLayer = theMapLayers.at( i );
00069     if ( !myLayer || !myLayer->isValid() )
00070     {
00071       QgsDebugMsg( "cannot add invalid layers" );
00072       continue;
00073     }
00074     //check the layer is not already registered!
00075     QMap<QString, QgsMapLayer*>::iterator myIterator =
00076       mMapLayers.find( myLayer->id() );
00077     //if myIterator returns mMapLayers.end() then it
00078     //does not exist in registry and its safe to add it
00079     if ( myIterator == mMapLayers.end() )
00080     {
00081       mMapLayers[myLayer->id()] = myLayer;
00082       myResultList << mMapLayers[myLayer->id()];
00083       if ( theEmitSignal )
00084         emit layerWasAdded( myLayer );
00085     }
00086   }
00087   if ( theEmitSignal && myResultList.count() > 0 )
00088   {
00089     emit layersAdded( myResultList );
00090   }
00091   return myResultList;
00092 } // QgsMapLayerRegistry::addMapLayers
00093 
00094 //this is deprecated by addMapLayers and is just a thin wrapper for that
00095 QgsMapLayer *
00096 QgsMapLayerRegistry::addMapLayer( QgsMapLayer * theMapLayer,
00097                                   bool theEmitSignal )
00098 {
00099   QList<QgsMapLayer *> myList;
00100   myList.append( theMapLayer );
00101   addMapLayers( myList, theEmitSignal );
00102   return theMapLayer;
00103 } //  QgsMapLayerRegistry::addMapLayer
00104 
00105 //introduced in 1.8
00106 void QgsMapLayerRegistry::removeMapLayers( QStringList theLayerIds,
00107     bool theEmitSignal )
00108 {
00109   if ( theEmitSignal )
00110     emit layersWillBeRemoved( theLayerIds );
00111 
00112   foreach( const QString &myId, theLayerIds )
00113   {
00114     if ( theEmitSignal )
00115       emit layerWillBeRemoved( myId );
00116     delete mMapLayers[myId];
00117     mMapLayers.remove( myId );
00118   }
00119   emit layersWillBeRemoved( theLayerIds );
00120 }
00121 
00122 //deprecated 1.8 use removeMapLayers rather
00123 void QgsMapLayerRegistry::removeMapLayer( QString theLayerId,
00124     bool theEmitSignal )
00125 {
00126   QStringList myList;
00127   myList << theLayerId;
00128   removeMapLayers( myList, theEmitSignal );
00129 }
00130 
00131 void QgsMapLayerRegistry::removeAllMapLayers()
00132 {
00133   // moved before physically removing the layers
00134   emit removedAll();
00135 
00136   // now let all canvas observers know to clear themselves,
00137   // and then consequently any of their map legends
00138   QStringList myList;
00139   QMap<QString, QgsMapLayer *>::iterator it;
00140   for ( it = mMapLayers.begin(); it != mMapLayers.end() ; ++it )
00141   {
00142     QString id = it.key();
00143     myList << id;
00144   }
00145   removeMapLayers( myList, false );
00146   mMapLayers.clear();
00147 } // QgsMapLayerRegistry::removeAllMapLayers()
00148 
00149 //Added in QGIS 1.4
00150 void QgsMapLayerRegistry::clearAllLayerCaches()
00151 {
00152   QMap<QString, QgsMapLayer *>::iterator it;
00153   for ( it = mMapLayers.begin(); it != mMapLayers.end() ; ++it )
00154   {
00155     //the map layer will take care of deleting the QImage
00156     it.value()->setCacheImage( 0 );
00157   }
00158 } // QgsMapLayerRegistry::clearAllLayerCaches()
00159 
00160 void QgsMapLayerRegistry::reloadAllLayers()
00161 {
00162   QMap<QString, QgsMapLayer *>::iterator it;
00163   for ( it = mMapLayers.begin(); it != mMapLayers.end() ; ++it )
00164   {
00165     QgsMapLayer* layer = it.value();
00166     if ( layer )
00167     {
00168       layer->reload();
00169     }
00170   }
00171 }
00172 
00173 QMap<QString, QgsMapLayer*> & QgsMapLayerRegistry::mapLayers()
00174 {
00175   return mMapLayers;
00176 }
00177 
00178 
00179 
00180 void QgsMapLayerRegistry::connectNotify( const char * signal )
00181 {
00182   Q_UNUSED( signal );
00183   //QgsDebugMsg("QgsMapLayerRegistry connected to " + QString(signal));
00184 } //  QgsMapLayerRegistry::connectNotify
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