[composer] Fix attribute table column sort order could not be changed after initially adding columns to sort

Author: nyalldawson

python/core/composer/qgscomposerattributetablemodel.sip

@@ -153,6 +153,11 @@ class QgsComposerTableSortColumnsProxyModel : QSortFilterProxyModel
      */
     QgsComposerTableColumn* columnFromSourceIndex( const QModelIndex& sourceIndex ) const;
 
+    /**Invalidates the current filter used by the proxy model
+     * @note added in 2.3
+     */
+    void resetFilter();
+
   protected:
     bool filterAcceptsRow( int source_row, const QModelIndex & source_parent ) const;
 

src/app/composer/qgsattributeselectiondialog.cpp

@@ -350,6 +350,9 @@ void QgsAttributeSelectionDialog::on_mAddSortColumnPushButton_clicked()
   }
 
   mColumnModel->setColumnAsSorted( column, mOrderComboBox->currentIndex() == 0 ? Qt::AscendingOrder : Qt::DescendingOrder );
+
+  //required so that rows can be reordered if initially no rows were shown in the table view
+  mSortedProxyModel->resetFilter();
 }
 
 void QgsAttributeSelectionDialog::on_mRemoveSortColumnPushButton_clicked()

src/core/composer/qgscomposerattributetablemodel.cpp

@@ -591,3 +591,8 @@ QgsComposerTableColumn *QgsComposerTableSortColumnsProxyModel::columnFromRow( in
   QModelIndex proxyIndex = index( row, 0 );
   return columnFromIndex( proxyIndex );
 }
+
+void QgsComposerTableSortColumnsProxyModel::resetFilter()
+{
+  invalidate();
+}

src/core/composer/qgscomposerattributetablemodel.h

@@ -183,6 +183,11 @@ class CORE_EXPORT QgsComposerTableSortColumnsProxyModel: public QSortFilterProxy
      */
     QgsComposerTableColumn* columnFromSourceIndex( const QModelIndex& sourceIndex ) const;
 
+    /**Invalidates the current filter used by the proxy model
+     * @note added in 2.3
+     */
+    void resetFilter();
+
   protected:
     bool filterAcceptsRow( int source_row, const QModelIndex & source_parent ) const;