Allow not set choice in QgsMapLayerComboBox

qgis · Nov 16, 2016 · 959f97f · 959f97f
1 parent 6638569
commit 959f97f
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Showing 9 changed files with 424 additions and 10 deletions.
diff --git a/python/core/qgsmaplayermodel.sip b/python/core/qgsmaplayermodel.sip
@@ -19,6 +19,7 @@ class QgsMapLayerModel : QAbstractItemModel
     {
       LayerIdRole, /*!< Stores the map layer ID */
       LayerRole, /*!< Stores pointer to the map layer itself */
+      IsEmptyRole, //!< True if index corresponds to the empty (not set) value
     };
 
     /**
@@ -38,6 +39,21 @@ class QgsMapLayerModel : QAbstractItemModel
      * @brief checkAll changes the checkstate for all the layers
      */
     void checkAll( Qt::CheckState checkState );
+
+    /**
+     * Sets whether an optional empty layer ("not set") option is present in the model.
+     * @see allowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    void setAllowEmptyLayer( bool allowEmpty );
+
+    /**
+     * Returns true if the model allows the empty layer ("not set") choice.
+     * @see setAllowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    bool allowEmptyLayer() const;
+
     /**
      * @brief layersChecked returns the list of layers which are checked (or unchecked)
      */

diff --git a/python/gui/qgsmaplayercombobox.sip b/python/gui/qgsmaplayercombobox.sip
@@ -28,6 +28,20 @@ class QgsMapLayerComboBox : QComboBox
     //! returns the list of excepted layers
     QList<QgsMapLayer*> exceptedLayerList() const;
 
+    /**
+     * Sets whether an optional empty layer ("not set") option is shown in the combo box.
+     * @see allowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    void setAllowEmptyLayer( bool allowEmpty );
+
+    /**
+     * Returns true if the combo box allows the empty layer ("not set") choice.
+     * @see setAllowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    bool allowEmptyLayer() const;
+
     /** Returns the current layer selected in the combo box.
      * @see layer
      */

diff --git a/src/core/qgsmaplayermodel.cpp b/src/core/qgsmaplayermodel.cpp
@@ -26,6 +26,7 @@ QgsMapLayerModel::QgsMapLayerModel( const QList<QgsMapLayer *>& layers, QObject
     : QAbstractItemModel( parent )
     , mLayersChecked( QMap<QString, Qt::CheckState>() )
     , mItemCheckable( false )
+    , mAllowEmpty( false )
 {
   connect( QgsMapLayerRegistry::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
   addLayers( layers );
@@ -35,6 +36,7 @@ QgsMapLayerModel::QgsMapLayerModel( QObject *parent )
     : QAbstractItemModel( parent )
     , mLayersChecked( QMap<QString, Qt::CheckState>() )
     , mItemCheckable( false )
+    , mAllowEmpty( false )
 {
   connect( QgsMapLayerRegistry::instance(), SIGNAL( layersAdded( QList<QgsMapLayer*> ) ), this, SLOT( addLayers( QList<QgsMapLayer*> ) ) );
   connect( QgsMapLayerRegistry::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
@@ -55,6 +57,25 @@ void QgsMapLayerModel::checkAll( Qt::CheckState checkState )
   emit dataChanged( index( 0, 0 ), index( mLayers.length() - 1, 0 ) );
 }
 
+void QgsMapLayerModel::setAllowEmptyLayer( bool allowEmpty )
+{
+  if ( allowEmpty == mAllowEmpty )
+    return;
+
+  if ( allowEmpty )
+  {
+    beginInsertRows( QModelIndex(), 0, 0 );
+    mAllowEmpty = true;
+    endInsertRows();
+  }
+  else
+  {
+    beginRemoveRows( QModelIndex(), 0, 0 );
+    mAllowEmpty = false;
+    endRemoveRows();
+  }
+}
+
 QList<QgsMapLayer *> QgsMapLayerModel::layersChecked( Qt::CheckState checkState )
 {
   QList<QgsMapLayer *> layers;
@@ -71,6 +92,8 @@ QList<QgsMapLayer *> QgsMapLayerModel::layersChecked( Qt::CheckState checkState
 QModelIndex QgsMapLayerModel::indexFromLayer( QgsMapLayer *layer ) const
 {
   int r = mLayers.indexOf( layer );
+  if ( r >= 0 && mAllowEmpty )
+    r++;
   return index( r, 0 );
 }
 
@@ -93,7 +116,11 @@ void QgsMapLayerModel::removeLayers( const QStringList& layerIds )
 
 void QgsMapLayerModel::addLayers( const QList<QgsMapLayer *>& layers )
 {
-  beginInsertRows( QModelIndex(), mLayers.count(), mLayers.count() + layers.count() - 1 );
+  int offset = 0;
+  if ( mAllowEmpty )
+    offset++;
+
+  beginInsertRows( QModelIndex(), mLayers.count() + offset, mLayers.count() + layers.count() - 1  + offset );
   Q_FOREACH ( QgsMapLayer* layer, layers )
   {
     mLayers.append( layer );
@@ -104,9 +131,17 @@ void QgsMapLayerModel::addLayers( const QList<QgsMapLayer *>& layers )
 
 QModelIndex QgsMapLayerModel::index( int row, int column, const QModelIndex &parent ) const
 {
+  int offset = 0;
+  if ( mAllowEmpty )
+    offset++;
+
   if ( hasIndex( row, column, parent ) )
   {
-    return createIndex( row, column, mLayers[row] );
+    QgsMapLayer* layer = nullptr;
+    if ( row - offset >= 0 && row - offset < mLayers.count() )
+      layer = mLayers.at( row - offset );
+
+    return createIndex( row, column, layer );
   }
 
   return QModelIndex();
@@ -122,7 +157,10 @@ QModelIndex QgsMapLayerModel::parent( const QModelIndex &child ) const
 
 int QgsMapLayerModel::rowCount( const QModelIndex &parent ) const
 {
-  return parent.isValid() ? 0 : mLayers.length();
+  if ( parent.isValid() )
+    return 0;
+
+  return ( mAllowEmpty ? 1 : 0 ) + mLayers.length();
 }
 
 int QgsMapLayerModel::columnCount( const QModelIndex &parent ) const
@@ -134,35 +172,58 @@ int QgsMapLayerModel::columnCount( const QModelIndex &parent ) const
 
 QVariant QgsMapLayerModel::data( const QModelIndex &index, int role ) const
 {
-  if ( !index.isValid() || !index.internalPointer() )
+  bool isEmpty = index.row() == 0 && mAllowEmpty;
+
+  if ( !index.isValid() )
     return QVariant();
 
   if ( role == Qt::DisplayRole )
   {
+    if ( index.row() == 0 && mAllowEmpty )
+      return QVariant();
+
     QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
-    return layer->name();
+    return layer ? layer->name() : QVariant();
   }
 
   if ( role == LayerIdRole )
   {
+    if ( isEmpty )
+      return QVariant();
+
     QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
-    return layer->id();
+    return layer ? layer->id() : QVariant();
   }
 
   if ( role == LayerRole )
   {
+    if ( isEmpty )
+      return QVariant();
+
     return QVariant::fromValue<QgsMapLayer*>( static_cast<QgsMapLayer*>( index.internalPointer() ) );
   }
 
+  if ( role == IsEmptyRole )
+    return isEmpty;
+
   if ( role == Qt::CheckStateRole && mItemCheckable )
   {
+    if ( isEmpty )
+      return QVariant();
+
     QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
-    return mLayersChecked[layer->id()];
+    return layer ? mLayersChecked[layer->id()] : QVariant();
   }
 
   if ( role == Qt::DecorationRole )
   {
+    if ( isEmpty )
+      return QVariant();
+
     QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
+    if ( !layer )
+      return QVariant();
+
     QgsMapLayer::LayerType type = layer->type();
     if ( role == Qt::DecorationRole )
     {
@@ -232,8 +293,10 @@ Qt::ItemFlags QgsMapLayerModel::flags( const QModelIndex &index ) const
     return 0;
   }
 
+  bool isEmpty = index.row() == 0 && mAllowEmpty;
+
   Qt::ItemFlags flags = Qt::ItemIsEnabled | Qt::ItemIsSelectable;
-  if ( mItemCheckable )
+  if ( mItemCheckable && !isEmpty )
   {
     flags |= Qt::ItemIsUserCheckable;
   }
@@ -243,7 +306,9 @@ Qt::ItemFlags QgsMapLayerModel::flags( const QModelIndex &index ) const
 
 bool QgsMapLayerModel::setData( const QModelIndex &index, const QVariant &value, int role )
 {
-  if ( role == Qt::CheckStateRole )
+  bool isEmpty = index.row() == 0 && mAllowEmpty;
+
+  if ( role == Qt::CheckStateRole && !isEmpty )
   {
     QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
     mLayersChecked[layer->id()] = ( Qt::CheckState )value.toInt();

diff --git a/src/core/qgsmaplayermodel.h b/src/core/qgsmaplayermodel.h
@@ -39,6 +39,7 @@ class CORE_EXPORT QgsMapLayerModel : public QAbstractItemModel
     {
       LayerIdRole = Qt::UserRole + 1, //!< Stores the map layer ID
       LayerRole, //!< Stores pointer to the map layer itself
+      IsEmptyRole, //!< True if index corresponds to the empty (not set) value
     };
 
     /**
@@ -61,6 +62,20 @@ class CORE_EXPORT QgsMapLayerModel : public QAbstractItemModel
      */
     void checkAll( Qt::CheckState checkState );
 
+    /**
+     * Sets whether an optional empty layer ("not set") option is present in the model.
+     * @see allowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    void setAllowEmptyLayer( bool allowEmpty );
+
+    /**
+     * Returns true if the model allows the empty layer ("not set") choice.
+     * @see setAllowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    bool allowEmptyLayer() const { return mAllowEmpty; }
+
     /**
      * @brief layersChecked returns the list of layers which are checked (or unchecked)
      */
@@ -73,7 +88,6 @@ class CORE_EXPORT QgsMapLayerModel : public QAbstractItemModel
      */
     QModelIndex indexFromLayer( QgsMapLayer* layer ) const;
 
-
   protected slots:
     void removeLayers( const QStringList& layerIds );
     void addLayers( const QList<QgsMapLayer*>& layers );
@@ -100,6 +114,10 @@ class CORE_EXPORT QgsMapLayerModel : public QAbstractItemModel
 
     bool setData( const QModelIndex &index, const QVariant &value, int role ) override;
     Qt::ItemFlags flags( const QModelIndex &index ) const override;
+
+  private:
+
+    bool mAllowEmpty;
 };
 
 #endif // QGSMAPLAYERMODEL_H
diff --git a/src/core/qgsmaplayerproxymodel.cpp b/src/core/qgsmaplayerproxymodel.cpp
@@ -77,6 +77,10 @@ bool QgsMapLayerProxyModel::filterAcceptsRow( int source_row, const QModelIndex
     return true;
 
   QModelIndex index = sourceModel()->index( source_row, 0, source_parent );
+
+  if ( sourceModel()->data( index, QgsMapLayerModel::IsEmptyRole ).toBool() )
+    return true;
+
   QgsMapLayer* layer = static_cast<QgsMapLayer*>( index.internalPointer() );
   if ( !layer )
     return false;
@@ -123,6 +127,12 @@ bool QgsMapLayerProxyModel::filterAcceptsRow( int source_row, const QModelIndex
 
 bool QgsMapLayerProxyModel::lessThan( const QModelIndex &left, const QModelIndex &right ) const
 {
+  // empty row is always first
+  if ( sourceModel()->data( left, QgsMapLayerModel::IsEmptyRole ).toBool() )
+    return true;
+  else if ( sourceModel()->data( right, QgsMapLayerModel::IsEmptyRole ).toBool() )
+    return false;
+
   // default mode is alphabetical order
   QString leftStr = sourceModel()->data( left ).toString();
   QString rightStr = sourceModel()->data( right ).toString();

diff --git a/src/gui/qgsmaplayercombobox.cpp b/src/gui/qgsmaplayercombobox.cpp
@@ -28,6 +28,16 @@ QgsMapLayerComboBox::QgsMapLayerComboBox( QWidget *parent )
   connect( mProxyModel, SIGNAL( rowsRemoved( QModelIndex, int, int ) ), this, SLOT( rowsChanged() ) );
 }
 
+void QgsMapLayerComboBox::setAllowEmptyLayer( bool allowEmpty )
+{
+  mProxyModel->sourceLayerModel()->setAllowEmptyLayer( allowEmpty );
+}
+
+bool QgsMapLayerComboBox::allowEmptyLayer() const
+{
+  return mProxyModel->sourceLayerModel()->allowEmptyLayer();
+}
+
 void QgsMapLayerComboBox::setLayer( QgsMapLayer *layer )
 {
   if ( !layer )

diff --git a/src/gui/qgsmaplayercombobox.h b/src/gui/qgsmaplayercombobox.h
@@ -53,6 +53,20 @@ class GUI_EXPORT QgsMapLayerComboBox : public QComboBox
     //! returns the list of excepted layers
     QList<QgsMapLayer*> exceptedLayerList() const {return mProxyModel->exceptedLayerList();}
 
+    /**
+     * Sets whether an optional empty layer ("not set") option is shown in the combo box.
+     * @see allowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    void setAllowEmptyLayer( bool allowEmpty );
+
+    /**
+     * Returns true if the combo box allows the empty layer ("not set") choice.
+     * @see setAllowEmptyLayer()
+     * @note added in QGIS 3.0
+     */
+    bool allowEmptyLayer() const;
+
     /** Returns the current layer selected in the combo box.
      * @see layer
      */

diff --git a/tests/src/python/CMakeLists.txt b/tests/src/python/CMakeLists.txt
@@ -57,6 +57,7 @@ ADD_PYTHON_TEST(PyQgsGeometryValidator test_qgsgeometryvalidator.py)
 ADD_PYTHON_TEST(PyQgsGraduatedSymbolRenderer test_qgsgraduatedsymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsInterval test_qgsinterval.py)
 ADD_PYTHON_TEST(PyQgsJSONUtils test_qgsjsonutils.py)
+ADD_PYTHON_TEST(PyQgsMapLayerModel test_qgsmaplayermodel.py)
 ADD_PYTHON_TEST(PyQgsMapUnitScale test_qgsmapunitscale.py)
 ADD_PYTHON_TEST(PyQgsMemoryProvider test_provider_memory.py)
 ADD_PYTHON_TEST(PyQgsMultiEditToolButton test_qgsmultiedittoolbutton.py)