[composer] Keep atlas page combo in sync when atlas feature changes

Author: nyalldawson

src/app/composer/qgscomposer.cpp

@@ -633,6 +633,7 @@ QgsComposer::QgsComposer( QgisApp *qgis, const QString& title )
   connect( atlasMap, SIGNAL( toggled( bool ) ), this, SLOT( toggleAtlasControls( bool ) ) );
   connect( atlasMap, SIGNAL( coverageLayerChanged( QgsVectorLayer* ) ), this, SLOT( updateAtlasMapLayerAction( QgsVectorLayer * ) ) );
   connect( atlasMap, SIGNAL( numberFeaturesChanged( int ) ), this, SLOT( updateAtlasPageComboBox( int ) ) );
+  connect( atlasMap, SIGNAL( featureChanged( QgsFeature* ) ), this, SLOT( atlasFeatureChanged( QgsFeature* ) ) );
 
   //default printer page setup
   setPrinterPageDefaults();
@@ -1007,6 +1008,27 @@ void QgsComposer::updateAtlasPageComboBox( int pageCount )
   mAtlasPageComboBox->blockSignals( false );
 }
 
+void QgsComposer::atlasFeatureChanged( QgsFeature *feature )
+{
+  Q_UNUSED( feature );
+
+  if ( !mComposition )
+    return;
+
+  mAtlasPageComboBox->blockSignals( true );
+  //prefer to set index of current atlas page, if combo box is showing enough page items
+  if ( mComposition->atlasComposition().currentFeatureNumber() < mAtlasPageComboBox->count() )
+  {
+    mAtlasPageComboBox->setCurrentIndex( mComposition->atlasComposition().currentFeatureNumber() );
+  }
+  else
+  {
+    //fallback to setting the combo text to the page number
+    mAtlasPageComboBox->setEditText( QString::number( mComposition->atlasComposition().currentFeatureNumber() + 1 ) );
+  }
+  mAtlasPageComboBox->blockSignals( false );
+}
+
 void QgsComposer::on_mActionAtlasPreview_triggered( bool checked )
 {
   QgsAtlasComposition* atlasMap = &mComposition->atlasComposition();
@@ -1134,7 +1156,7 @@ void QgsComposer::atlasPageComboEditingFinished()
   QString text = mAtlasPageComboBox->lineEdit()->text();
   bool ok = false;
   int page = text.toInt( &ok );
-  if ( !ok || page >= mComposition->atlasComposition().numFeatures() )
+  if ( !ok || page >= mComposition->atlasComposition().numFeatures() || page < 1 )
   {
     mAtlasPageComboBox->blockSignals( true );
     mAtlasPageComboBox->setCurrentIndex( mComposition->atlasComposition().currentFeatureNumber() );
@@ -1462,6 +1484,7 @@ void QgsComposer::setComposition( QgsComposition* composition )
   connect( atlasMap, SIGNAL( toggled( bool ) ), this, SLOT( toggleAtlasControls( bool ) ) );
   connect( atlasMap, SIGNAL( coverageLayerChanged( QgsVectorLayer* ) ), this, SLOT( updateAtlasMapLayerAction( QgsVectorLayer * ) ) );
   connect( atlasMap, SIGNAL( numberFeaturesChanged( int ) ), this, SLOT( updateAtlasPageComboBox( int ) ) );
+  connect( atlasMap, SIGNAL( featureChanged( QgsFeature* ) ), this, SLOT( atlasFeatureChanged( QgsFeature* ) ) );
 
   //default printer page setup
   setPrinterPageDefaults();
@@ -3281,6 +3304,7 @@ void QgsComposer::readXML( const QDomElement& composerElem, const QDomDocument&
   connect( atlasMap, SIGNAL( toggled( bool ) ), this, SLOT( toggleAtlasControls( bool ) ) );
   connect( atlasMap, SIGNAL( coverageLayerChanged( QgsVectorLayer* ) ), this, SLOT( updateAtlasMapLayerAction( QgsVectorLayer * ) ) );
   connect( atlasMap, SIGNAL( numberFeaturesChanged( int ) ), this, SLOT( updateAtlasPageComboBox( int ) ) );
+  connect( atlasMap, SIGNAL( featureChanged( QgsFeature* ) ), this, SLOT( atlasFeatureChanged( QgsFeature* ) ) );
 
   //default printer page setup
   setPrinterPageDefaults();

src/app/composer/qgscomposer.h

@@ -657,6 +657,8 @@ class QgsComposer: public QMainWindow, private Ui::QgsComposerBase
     /** Repopulates the atlas page combo box with valid items.
      */
     void updateAtlasPageComboBox( int pageCount );
+
+    void atlasFeatureChanged( QgsFeature* feature );
 };
 
 #endif