[composer] New QSortFilterProxyModel for filtering items by type

and new widget QgsComposerItemComboBox for showing matching composer
items.

Swap existing comboboxes to use the new widget, which removes a lot
of fragile code designed to allow selection of items. Additionally
the combobox now show the correct item id rather than always showing
"Map 0/1/..."

python/core/composer/qgscomposermodel.sip

@@ -23,6 +23,14 @@ class QgsComposerModel : QAbstractItemModel
 %End
   public:
 
+    //! Columns returned by the model
+    enum Columns
+    {
+      Visibility, /*!< Item visibility check box */
+      LockStatus, /*!< Item lock status check box */
+      ItemId, /*!< Item ID */
+    };
+
     /** Constructor
      * @param composition composition to attach to
      * @param parent parent object
@@ -202,6 +210,13 @@ class QgsComposerModel : QAbstractItemModel
      */
     void updateItemSelectStatus( QgsComposerItem *item );
 
+    /** Returns the QModelIndex corresponding to a QgsComposerItem, if possible
+     * @param item QgsComposerItem to find index for
+     * @param column column number for created QModelIndex
+     * @returns QModelIndex corresponding to item and specified column
+     */
+    QModelIndex indexForItem( QgsComposerItem *item, const int column = 0 );
+
   public slots:
 
     /** Sets an item as the current selection from a QModelIndex
@@ -210,3 +225,65 @@ class QgsComposerModel : QAbstractItemModel
      */
     void setSelected( const QModelIndex &index );
 };
+
+
+/**
+ * /class QgsComposerProxyModel
+ * /ingroup core
+ * /brief Allows for filtering a QgsComposerModel by item type.
+ * /note added in 2.16
+ */
+class QgsComposerProxyModel: QSortFilterProxyModel
+{
+%TypeHeaderCode
+#include "qgscomposermodel.h"
+%End
+  public:
+
+    /** Constructor for QgsComposerProxyModel.
+     * @param composition composition to attach model to
+     * @param parent optional parent
+     */
+    QgsComposerProxyModel( QgsComposition* composition, QObject *parent /TransferThis/ = nullptr );
+
+    /** Returns the current item type filter, or QgsComposerItem::ComposerItem if no
+     * item type filter is set.
+     * @see setFilterType()
+     */
+    QgsComposerItem::ItemType filterType() const;
+
+    /** Sets the item type filter. Only matching item types will be shown.
+     * @param itemType type to filter. Set to QgsComposerItem::ComposerItem to show all
+     * item types.
+     * @see filterType()
+     */
+    void setFilterType( QgsComposerItem::ItemType itemType );
+
+    /** Sets a list of specific items to exclude from the model
+     * @param exceptList list of items to exclude
+     * @see exceptedItemList()
+     */
+    void setExceptedItemList( const QList< QgsComposerItem* >& exceptList );
+
+    /** Returns the list of specific items excluded from the model.
+     * @see setExceptedItemList()
+     */
+    QList< QgsComposerItem* > exceptedItemList() const;
+
+    /** Returns the QgsComposerModel used in this proxy model.
+     */
+    QgsComposerModel* sourceLayerModel() const;
+
+    /** Returns the QgsComposerItem corresponding to an index from the source
+     * QgsComposerModel model.
+     * @param sourceIndex a QModelIndex
+     * @returns QgsComposerItem for specified index from QgsComposerModel
+     */
+    QgsComposerItem* itemFromSourceIndex( const QModelIndex& sourceIndex ) const;
+
+  protected:
+    bool filterAcceptsRow( int source_row, const QModelIndex & source_parent ) const;
+    bool lessThan( const QModelIndex &left, const QModelIndex &right ) const;
+
+};
+

python/gui/gui.sip

@@ -49,6 +49,7 @@
 %Include qgscolorschemelist.sip
 %Include qgscolorswatchgrid.sip
 %Include qgscolorwidgets.sip
+%Include qgscomposeritemcombobox.sip
 %Include qgscomposerruler.sip
 %Include qgscomposerview.sip
 %Include qgscredentialdialog.sip

python/gui/qgscomposeritemcombobox.sip

@@ -0,0 +1,72 @@
+/**
+ * /class QgsComposerItemComboBox
+ * /ingroup gui
+ * /brief The QgsComposerItemComboBox class is a combo box which displays items of
+ * a matching type from a composition.
+ * /note added in 2.16
+ */
+class QgsComposerItemComboBox : QComboBox
+{
+%TypeHeaderCode
+#include "qgscomposeritemcombobox.h"
+%End
+
+  public:
+    /**
+     * QgsComposerItemComboBox creates a combo box to display a list of items in a
+     * composition. The items can optionally be filtered by type.
+     * @param parent parent widget
+     * @param composition composition to show items from. If not set, no items will be shown
+     * until setComposition() is called
+     */
+    explicit QgsComposerItemComboBox( QWidget* parent /TransferThis/ = nullptr, QgsComposition* composition = nullptr );
+
+    /** Sets the composition containing the items to list in the combo box.
+     */
+    void setComposition( QgsComposition* composition );
+
+    /** Sets a filter for the item type to show in the combo box.
+     * @param itemType type of items to show. Set to QgsComposerItem::ComposerItem to
+     * show all items.
+     * @see itemType()
+     */
+    void setItemType( QgsComposerItem::ItemType itemType );
+
+    /** Returns the filter for the item types to show in the combo box.
+     * @see setItemType()
+     */
+    QgsComposerItem::ItemType itemType() const;
+
+    /** Sets a list of specific items to exclude from the combo box.
+     * @param exceptList list of items to exclude
+     * @see exceptedItemList()
+     */
+    void setExceptedItemList( const QList< QgsComposerItem* >& exceptList );
+
+    /** Returns the list of specific items excluded from the combo box.
+     * @see setExceptedItemList()
+     */
+    QList< QgsComposerItem* > exceptedItemList() const;
+
+    /** Return the item currently shown at the specified index within the combo box.
+     * @param index position of item to return
+     * @see currentItem()
+     */
+    const QgsComposerItem* item( int index ) const;
+
+    /** Returns the item currently selected in the combo box.
+     */
+    const QgsComposerItem* currentItem() const;
+
+  public slots:
+    /** Sets the currently selected item in the combo box.
+     * @param item selected item
+     */
+    void setItem( const QgsComposerItem* item );
+
+  signals:
+
+    //! Emitted whenever the currently selected item changes
+    void itemChanged( QgsComposerItem* item );
+
+};

src/app/composer/qgscomposerattributetablewidget.cpp

@@ -61,7 +61,9 @@ QgsComposerAttributeTableWidget::QgsComposerAttributeTableWidget( QgsComposerAtt
   mLayerComboBox->setFilters( QgsMapLayerProxyModel::VectorLayer );
   connect( mLayerComboBox, SIGNAL( layerChanged( QgsMapLayer* ) ), this, SLOT( changeLayer( QgsMapLayer* ) ) );
 
-  refreshMapComboBox();
+  mComposerMapComboBox->setComposition( mComposerTable->composition() );
+  mComposerMapComboBox->setItemType( QgsComposerItem::ComposerMap );
+  connect( mComposerMapComboBox, SIGNAL( itemChanged( const QgsComposerItem* ) ), this, SLOT( composerMapChanged( const QgsComposerItem* ) ) );
 
   mHeaderFontColorButton->setColorDialogTitle( tr( "Select header font color" ) );
   mHeaderFontColorButton->setAllowAlpha( true );
@@ -80,7 +82,6 @@ QgsComposerAttributeTableWidget::QgsComposerAttributeTableWidget( QgsComposerAtt
   mBackgroundColorButton->setNoColorString( tr( "No background" ) );
 
   updateGuiElements();
-  on_mComposerMapComboBox_activated( mComposerMapComboBox->currentIndex() );
 
   if ( mComposerTable )
   {
@@ -107,47 +108,6 @@ QgsComposerAttributeTableWidget::QgsComposerAttributeTableWidget( QgsComposerAtt
 
 QgsComposerAttributeTableWidget::~QgsComposerAttributeTableWidget()
 {
-
-}
-
-void QgsComposerAttributeTableWidget::showEvent( QShowEvent* /* event */ )
-{
-  refreshMapComboBox();
-}
-
-void QgsComposerAttributeTableWidget::refreshMapComboBox()
-{
-  //save the current entry in case it is still present after refresh
-  QString saveCurrentComboText = mComposerMapComboBox->currentText();
-
-  mComposerMapComboBox->blockSignals( true );
-  mComposerMapComboBox->clear();
-  if ( mComposerTable )
-  {
-    const QgsComposition* tableComposition = mComposerTable->composition();
-    if ( tableComposition )
-    {
-      QList<const QgsComposerMap*> mapList = tableComposition->composerMapItems();
-      QList<const QgsComposerMap*>::const_iterator mapIt = mapList.constBegin();
-      for ( ; mapIt != mapList.constEnd(); ++mapIt )
-      {
-        int mapId = ( *mapIt )->id();
-        mComposerMapComboBox->addItem( tr( "Map %1" ).arg( mapId ), mapId );
-      }
-    }
-  }
-  mComposerMapComboBox->blockSignals( false );
-
-  if ( mComposerMapComboBox->findText( saveCurrentComboText ) == -1 )
-  {
-    //the former entry is no longer present. Inform the scalebar about the changed composer map
-    on_mComposerMapComboBox_activated( mComposerMapComboBox->currentIndex() );
-  }
-  else
-  {
-    //the former entry is still present. Make it the current entry again
-    mComposerMapComboBox->setCurrentIndex( mComposerMapComboBox->findText( saveCurrentComboText ) );
-  }
 }
 
 void QgsComposerAttributeTableWidget::on_mRefreshPushButton_clicked()
@@ -213,31 +173,24 @@ void QgsComposerAttributeTableWidget::on_mAttributesPushButton_clicked()
   }
 }
 
-void QgsComposerAttributeTableWidget::on_mComposerMapComboBox_activated( int index )
+void QgsComposerAttributeTableWidget::composerMapChanged( const QgsComposerItem* item )
 {
   if ( !mComposerTable )
   {
     return;
   }
 
-  QVariant itemData = mComposerMapComboBox->itemData( index );
-  if ( itemData.type() == QVariant::Invalid )
-  {
-    return;
-  }
-
-  int mapId = itemData.toInt();
   const QgsComposition* tableComposition = mComposerTable->composition();
   if ( tableComposition )
   {
     QgsComposition* composition = mComposerTable->composition();
-    if ( sender() && composition ) //only create command if called from GUI
+    if ( composition )
     {
       composition->beginMultiFrameCommand( mComposerTable, tr( "Table map changed" ) );
     }
-    mComposerTable->setComposerMap( tableComposition->getComposerMapById( mapId ) );
+    mComposerTable->setComposerMap( dynamic_cast< const QgsComposerMap* >( item ) );
     mComposerTable->update();
-    if ( sender() && composition )
+    if ( composition )
     {
       composition->endMultiFrameCommand();
     }
@@ -467,16 +420,7 @@ void QgsComposerAttributeTableWidget::updateGuiElements()
     }
   }
 
-  //map combo box
-  const QgsComposerMap* cm = mComposerTable->composerMap();
-  if ( cm )
-  {
-    int mapIndex = mComposerMapComboBox->findText( tr( "Map %1" ).arg( cm->id() ) );
-    if ( mapIndex != -1 )
-    {
-      mComposerMapComboBox->setCurrentIndex( mapIndex );
-    }
-  }
+  mComposerMapComboBox->setItem( mComposerTable->composerMap() );
   mMaximumRowsSpinBox->setValue( mComposerTable->maximumNumberOfFeatures() );
   mMarginSpinBox->setValue( mComposerTable->cellMargin() );
   mGridStrokeWidthSpinBox->setValue( mComposerTable->gridStrokeWidth() );

src/app/composer/qgscomposerattributetablewidget.h

@@ -31,16 +31,12 @@ class QgsComposerAttributeTableWidget: public QgsComposerItemBaseWidget, private
     QgsComposerAttributeTableWidget( QgsComposerAttributeTableV2* table, QgsComposerFrame* frame );
     ~QgsComposerAttributeTableWidget();
 
-  protected:
-    void showEvent( QShowEvent * event ) override;
-
   private:
     QgsComposerAttributeTableV2* mComposerTable;
     QgsComposerFrame* mFrame;
 
     /** Blocks / unblocks the signals of all GUI elements*/
     void blockAllSignals( bool b );
-    void refreshMapComboBox();
 
     void toggleSourceControls();
 
@@ -49,7 +45,7 @@ class QgsComposerAttributeTableWidget: public QgsComposerItemBaseWidget, private
   private slots:
     void on_mRefreshPushButton_clicked();
     void on_mAttributesPushButton_clicked();
-    void on_mComposerMapComboBox_activated( int index );
+    void composerMapChanged( const QgsComposerItem* item );
     void on_mMaximumRowsSpinBox_valueChanged( int i );
     void on_mMarginSpinBox_valueChanged( double d );
     void on_mGridStrokeWidthSpinBox_valueChanged( double d );