Merge pull request #4299 from alexbruy/checkable-combobox

[FEATURE] New custom widget checkable combobox

python/gui/gui.sip

@@ -37,6 +37,7 @@
 %Include qgscodeeditorcss.sip
 %End
 %Include qgscharacterselectdialog.sip
+%Include qgscheckablecombobox.sip
 %Include qgscolorbrewercolorrampdialog.sip
 %Include qgscolorbutton.sip
 %Include qgscolorrampbutton.sip

python/gui/qgscheckablecombobox.sip

@@ -0,0 +1,153 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgscheckablecombobox.h                                       *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+
+
+
+class QgsCheckableComboBox : QComboBox
+{
+
+%TypeHeaderCode
+#include "qgscheckablecombobox.h"
+%End
+  public:
+
+    QgsCheckableComboBox( QWidget *parent /TransferThis/ = 0 );
+%Docstring
+ Constructor for QgsCheckableComboBox.
+%End
+
+    QString separator() const;
+%Docstring
+ Returns separator used to separate items in the display text.
+ \see setSeparator()
+ :rtype: str
+%End
+
+    void setSeparator( const QString &separator );
+%Docstring
+ Set separator used to separate items in the display text.
+ \param separator separator to use
+ \see separator()
+%End
+
+    QString defaultText() const;
+%Docstring
+ Returns default text which will be displayed in the widget
+ when no items selected.
+ \see setDefaultText()
+ :rtype: str
+%End
+
+    void setDefaultText( const QString &text );
+%Docstring
+ Set default text which will be displayed in the widget when
+ no items selected.
+ \param text default text
+ \see defaultText()
+%End
+
+    QStringList checkedItems() const;
+%Docstring
+ Returns currently checked items.
+ \see setCheckedItems()
+ :rtype: list of str
+%End
+
+    Qt::CheckState itemCheckState( int index ) const;
+%Docstring
+ Returns the checked state of the item identified by index
+ \param index item index
+ \see setItemCheckState()
+ \see toggleItemCheckState()
+ :rtype: Qt.CheckState
+%End
+
+    void setItemCheckState( int index, Qt::CheckState state );
+%Docstring
+ Sets the item check state to state
+ \param index item index
+ \param state check state
+ \see itemCheckState()
+ \see toggleItemCheckState()
+%End
+
+    void toggleItemCheckState( int index );
+%Docstring
+ Toggles the item check state
+ \param index item index
+ \see itemCheckState()
+ \see setItemCheckState()
+%End
+
+    virtual void hidePopup();
+%Docstring
+ Hides the list of items in the combobox if it is currently
+ visible and resets the internal state.
+%End
+
+    virtual bool eventFilter( QObject *object, QEvent *event );
+%Docstring
+ Filters events to enable context menu
+ :rtype: bool
+%End
+
+  signals:
+
+    void checkedItemsChanged( const QStringList &items );
+%Docstring
+ This signal is emitted whenever the checked items list changed.
+%End
+
+  public slots:
+
+    void setCheckedItems( const QStringList &items );
+%Docstring
+ Set items which should be checked/selected.
+ \param items items to select
+ \see checkedItems()
+%End
+
+  protected:
+
+    virtual void resizeEvent( QResizeEvent *event );
+%Docstring
+ Handler for widget resizing
+%End
+
+  protected slots:
+
+    void showContextMenu( const QPoint &pos );
+%Docstring
+ Display context menu which allows to select/deselect
+ all items at once.
+%End
+
+    void selectAllOptions();
+%Docstring
+ Selects all items.
+%End
+
+    void deselectAllOptions();
+%Docstring
+ Removes selection from all items.
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgscheckablecombobox.h                                       *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

src/customwidgets/CMakeLists.txt

@@ -14,6 +14,7 @@ SET (QGIS_CUSTOMWIDGETS_SRCS
   qgiscustomwidgets.cpp
   qgscollapsiblegroupboxplugin.cpp
   qgscolorbuttonplugin.cpp
+  qgscheckablecomboboxplugin.cpp
   qgsdatetimeeditplugin.cpp
   qgsdockwidgetplugin.cpp
   qgsdoublespinboxplugin.cpp
@@ -40,6 +41,7 @@ SET (QGIS_CUSTOMWIDGETS_MOC_HDRS
   qgiscustomwidgets.h
   qgscollapsiblegroupboxplugin.h
   qgscolorbuttonplugin.h
+  qgscheckablecomboboxplugin.h
   qgsdatetimeeditplugin.h
   qgsdockwidgetplugin.h
   qgsdoublespinboxplugin.h

src/customwidgets/qgscheckablecomboboxplugin.cpp

@@ -0,0 +1,97 @@
+/***************************************************************************
+   qgscheckablecomboboxplugin.cpp
+    --------------------------------------
+   Date                 : March 22, 2017
+   Copyright            : (C) 2017 Alexander Bruy
+   Email                : alexander dot bruy at gmail dot com
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************/
+
+#include "qgiscustomwidgets.h"
+#include "qgscheckablecombobox.h"
+#include "qgscheckablecomboboxplugin.h"
+
+
+QgsCheckableComboBoxPlugin::QgsCheckableComboBoxPlugin( QObject *parent )
+  : QObject( parent )
+  , mInitialized( false )
+{
+}
+
+
+QString QgsCheckableComboBoxPlugin::name() const
+{
+  return "QgsCheckableComboBox";
+}
+
+QString QgsCheckableComboBoxPlugin::group() const
+{
+  return QgisCustomWidgets::groupName();
+}
+
+QString QgsCheckableComboBoxPlugin::includeFile() const
+{
+  return "qgscheckablecombobox.h";
+}
+
+QIcon QgsCheckableComboBoxPlugin::icon() const
+{
+  return QIcon( ":/images/icons/qgis-icon-60x60.png" );
+}
+
+bool QgsCheckableComboBoxPlugin::isContainer() const
+{
+  return false;
+}
+
+QWidget *QgsCheckableComboBoxPlugin::createWidget( QWidget *parent )
+{
+  return new QgsCheckableComboBox( parent );
+}
+
+bool QgsCheckableComboBoxPlugin::isInitialized() const
+{
+  return mInitialized;
+}
+
+void QgsCheckableComboBoxPlugin::initialize( QDesignerFormEditorInterface *core )
+{
+  Q_UNUSED( core );
+  if ( mInitialized )
+    return;
+  mInitialized = true;
+}
+
+
+QString QgsCheckableComboBoxPlugin::toolTip() const
+{
+  return "";
+}
+
+QString QgsCheckableComboBoxPlugin::whatsThis() const
+{
+  return "";
+}
+
+QString QgsCheckableComboBoxPlugin::domXml() const
+{
+  return QString( "<ui language=\"c++\">\n"
+                  " <widget class=\"%1\" name=\"mComboBox\">\n"
+                  "  <property name=\"geometry\">\n"
+                  "   <rect>\n"
+                  "    <x>0</x>\n"
+                  "    <y>0</y>\n"
+                  "    <width>160</width>\n"
+                  "    <height>27</height>\n"
+                  "   </rect>\n"
+                  "  </property>\n"
+                  " </widget>\n"
+                  "</ui>\n" )
+         .arg( name() );
+}

src/customwidgets/qgscheckablecomboboxplugin.h

@@ -0,0 +1,51 @@
+/***************************************************************************
+   qgscheckablecomboboxplugin.h
+    --------------------------------------
+   Date                 : March 22, 2017
+   Copyright            : (C) 2017 Alexander Bruy
+   Email                : alexander dot bruy at gmail dot com
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************/
+
+#ifndef QGSCHECKABLECOMBOBOXPLUGIN_H
+#define QGSCHECKABLECOMBOBOXPLUGIN_H
+
+
+#include <QtGlobal>
+#include <QtUiPlugin/QDesignerCustomWidgetInterface>
+#include <QtUiPlugin/QDesignerExportWidget>
+#include "qgis_customwidgets.h"
+
+
+class CUSTOMWIDGETS_EXPORT QgsCheckableComboBoxPlugin : public QObject, public QDesignerCustomWidgetInterface
+{
+    Q_OBJECT
+    Q_INTERFACES( QDesignerCustomWidgetInterface )
+
+  public:
+    explicit QgsCheckableComboBoxPlugin( QObject *parent = 0 );
+
+  private:
+    bool mInitialized = false;
+
+    // QDesignerCustomWidgetInterface interface
+  public:
+    QString name() const override;
+    QString group() const override;
+    QString includeFile() const override;
+    QIcon icon() const override;
+    bool isContainer() const override;
+    QWidget *createWidget( QWidget *parent ) override;
+    bool isInitialized() const override;
+    void initialize( QDesignerFormEditorInterface *core ) override;
+    QString toolTip() const override;
+    QString whatsThis() const override;
+    QString domXml() const override;
+};
+#endif // QGSCHECKABLECOMBOBOXPLUGIN_H

src/customwidgets/qgspasswordlineeditplugin.cpp

@@ -1,5 +1,5 @@
 /***************************************************************************
-   qgsfilterlineeditplugin.cpp
+   qgspasswordlineeditplugin.cpp
     --------------------------------------
    Date                 : March 13, 2017
    Copyright            : (C) 2017 Alexander Bruy

src/gui/CMakeLists.txt

@@ -172,6 +172,7 @@ SET(QGIS_GUI_SRCS
   qgsbrowsertreeview.cpp
   qgsbusyindicatordialog.cpp
   qgscharacterselectdialog.cpp
+  qgscheckablecombobox.cpp
   qgscodeeditor.cpp
   qgscodeeditorcss.cpp
   qgscodeeditorhtml.cpp
@@ -329,6 +330,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsbrowsertreeview.h
   qgsbusyindicatordialog.h
   qgscharacterselectdialog.h
+  qgscheckablecombobox.h
   qgscodeeditor.h
   qgscodeeditorcss.h
   qgscodeeditorhtml.h

src/gui/qgscheckablecombobox.cpp

@@ -0,0 +1,266 @@
+/***************************************************************************
+                              qgscheckablecombobox.cpp
+                              ------------------------
+  begin                : March 21, 2017
+  copyright            : (C) 2017 by Alexander Bruy
+  email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgscheckablecombobox.h"
+
+#include <QEvent>
+#include <QMouseEvent>
+#include <QLineEdit>
+#include <QPoint>
+#include <QAbstractItemView>
+
+
+QgsCheckableItemModel::QgsCheckableItemModel( QObject *parent )
+  : QStandardItemModel( 0, 1, parent )
+{
+}
+
+Qt::ItemFlags QgsCheckableItemModel::flags( const QModelIndex &index ) const
+{
+  return QStandardItemModel::flags( index ) | Qt::ItemIsUserCheckable;
+}
+
+QVariant QgsCheckableItemModel::data( const QModelIndex &index, int role ) const
+{
+  QVariant value = QStandardItemModel::data( index, role );
+
+  if ( index.isValid() && role == Qt::CheckStateRole && !value.isValid() )
+  {
+    value = Qt::Unchecked;
+  }
+
+  return value;
+}
+
+bool QgsCheckableItemModel::setData( const QModelIndex &index, const QVariant &value, int role )
+{
+  bool ok = QStandardItemModel::setData( index, value, role );
+
+  if ( ok && role == Qt::CheckStateRole )
+  {
+    emit dataChanged( index, index );
+    emit itemCheckStateChanged();
+  }
+
+  return ok;
+}
+
+
+QgsCheckBoxDelegate::QgsCheckBoxDelegate( QObject *parent )
+  : QStyledItemDelegate( parent )
+{
+}
+
+void QgsCheckBoxDelegate::paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const
+{
+  QStyleOptionViewItem &nonConstOpt = const_cast<QStyleOptionViewItem &>( option );
+  nonConstOpt.showDecorationSelected = false;
+  QStyledItemDelegate::paint( painter, nonConstOpt, index );
+}
+
+
+QgsCheckableComboBox::QgsCheckableComboBox( QWidget *parent )
+  : QComboBox( parent )
+  , mSeparator( ", " )
+{
+  setModel( new QgsCheckableItemModel( this ) );
+  setItemDelegate( new QgsCheckBoxDelegate( this ) );
+
+  QLineEdit *lineEdit = new QLineEdit( this );
+  lineEdit->setReadOnly( true );
+  setLineEdit( lineEdit );
+
+  mContextMenu = new QMenu( this );
+  mSelectAllAction = mContextMenu->addAction( tr( "Select all" ) );
+  mDeselectAllAction = mContextMenu->addAction( tr( "Deselect all" ) );
+  connect( mSelectAllAction, &QAction::triggered, this, &QgsCheckableComboBox::selectAllOptions );
+  connect( mDeselectAllAction, &QAction::triggered, this, &QgsCheckableComboBox::deselectAllOptions );
+
+  view()->viewport()->installEventFilter( this );
+  view()->setContextMenuPolicy( Qt::CustomContextMenu );
+  connect( view(), &QAbstractItemView::customContextMenuRequested, this, &QgsCheckableComboBox::showContextMenu );
+
+  QgsCheckableItemModel *myModel = qobject_cast<QgsCheckableItemModel *>( model() );
+  connect( myModel, &QgsCheckableItemModel::itemCheckStateChanged, this, &QgsCheckableComboBox::updateCheckedItems );
+  connect( model(), &QStandardItemModel::rowsInserted, this, [ = ]( const QModelIndex &, int, int ) { updateCheckedItems(); } );
+  connect( model(), &QStandardItemModel::rowsRemoved, this, [ = ]( const QModelIndex &, int, int ) { updateCheckedItems(); } );
+
+  connect( this, static_cast< void ( QComboBox::* )( int ) >( &QComboBox::activated ), this, &QgsCheckableComboBox::toggleItemCheckState );
+}
+
+QString QgsCheckableComboBox::separator() const
+{
+  return mSeparator;
+}
+
+void QgsCheckableComboBox::setSeparator( const QString &separator )
+{
+  if ( mSeparator != separator )
+  {
+    mSeparator = separator;
+    updateDisplayText();
+  }
+}
+
+QString QgsCheckableComboBox::defaultText() const
+{
+  return mDefaultText;
+}
+
+void QgsCheckableComboBox::setDefaultText( const QString &text )
+{
+  if ( mDefaultText != text )
+  {
+    mDefaultText = text;
+    updateDisplayText();
+  }
+}
+
+QStringList QgsCheckableComboBox::checkedItems() const
+{
+  QStringList items;
+
+  if ( model() )
+  {
+    QModelIndex index = model()->index( 0, modelColumn(), rootModelIndex() );
+    QModelIndexList indexes = model()->match( index, Qt::CheckStateRole, Qt::Checked, -1, Qt::MatchExactly );
+    Q_FOREACH ( const QModelIndex &index, indexes )
+    {
+      items += index.data().toString();
+    }
+  }
+
+  return items;
+}
+
+Qt::CheckState QgsCheckableComboBox::itemCheckState( int index ) const
+{
+  return static_cast<Qt::CheckState>( itemData( index, Qt::CheckStateRole ).toInt() );
+}
+
+void QgsCheckableComboBox::setItemCheckState( int index, Qt::CheckState state )
+{
+  setItemData( index, state, Qt::CheckStateRole );
+}
+
+void QgsCheckableComboBox::toggleItemCheckState( int index )
+{
+  QVariant value = itemData( index, Qt::CheckStateRole );
+  if ( value.isValid() )
+  {
+    Qt::CheckState state = static_cast<Qt::CheckState>( value.toInt() );
+    setItemData( index, ( state == Qt::Unchecked ? Qt::Checked : Qt::Unchecked ), Qt::CheckStateRole );
+  }
+}
+
+void QgsCheckableComboBox::hidePopup()
+{
+  if ( !mSkipHide )
+  {
+    QComboBox::hidePopup();
+  }
+  mSkipHide = false;
+}
+
+void QgsCheckableComboBox::showContextMenu( const QPoint &pos )
+{
+  Q_UNUSED( pos );
+
+  mContextMenu->exec( QCursor::pos() );
+}
+
+void QgsCheckableComboBox::selectAllOptions()
+{
+  blockSignals( true );
+  for ( int i = 0;  i < count(); i++ )
+  {
+    setItemData( i, Qt::Checked, Qt::CheckStateRole );
+  }
+  blockSignals( false );
+  updateCheckedItems();
+}
+
+void QgsCheckableComboBox::deselectAllOptions()
+{
+  blockSignals( true );
+  for ( int i = 0;  i < count(); i++ )
+  {
+    setItemData( i, Qt::Unchecked, Qt::CheckStateRole );
+  }
+  blockSignals( false );
+  updateCheckedItems();
+}
+
+bool QgsCheckableComboBox::eventFilter( QObject *object, QEvent *event )
+{
+  if ( ( event->type() == QEvent::MouseButtonPress || event->type() == QEvent::MouseButtonRelease )
+       && object == view()->viewport() )
+  {
+    mSkipHide = true;
+  }
+
+  if ( event->type() == QEvent::MouseButtonRelease )
+  {
+    if ( static_cast<QMouseEvent *>( event )->button() == Qt::RightButton )
+    {
+      return true;
+    }
+  }
+  return false;
+}
+
+void QgsCheckableComboBox::setCheckedItems( const QStringList &items )
+{
+  Q_FOREACH ( const QString &text, items )
+  {
+    const int index = findText( text );
+    setItemCheckState( index, index != -1 ? Qt::Checked : Qt::Unchecked );
+  }
+}
+
+void QgsCheckableComboBox::resizeEvent( QResizeEvent *event )
+{
+  QComboBox::resizeEvent( event );
+  updateDisplayText();
+}
+
+void QgsCheckableComboBox::updateCheckedItems()
+{
+  QStringList items = checkedItems();
+  updateDisplayText();
+  emit checkedItemsChanged( items );
+}
+
+void QgsCheckableComboBox::updateDisplayText()
+{
+  QString text;
+  QStringList items = checkedItems();
+  if ( items.isEmpty() )
+  {
+    text = mDefaultText;
+  }
+  else
+  {
+    text = items.join( mSeparator );
+  }
+
+  QRect rect = lineEdit()->rect();
+  QFontMetrics fontMetrics( font() );
+  text = fontMetrics.elidedText( text, Qt::ElideRight, rect.width() );
+  setEditText( text );
+}
+

src/gui/qgscheckablecombobox.h

@@ -0,0 +1,238 @@
+/***************************************************************************
+                              qgscheckablecombobox.h
+                              ------------------------
+  begin                : March 21, 2017
+  copyright            : (C) 2017 by Alexander Bruy
+  email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSCHECKABLECOMBOBOX_H
+#define QGSCHECKABLECOMBOBOX_H
+
+#include <QComboBox>
+#include <QMenu>
+#include <QStandardItemModel>
+#include <QStyledItemDelegate>
+
+#include "qgis.h"
+#include "qgis_gui.h"
+
+class QEvent;
+
+/** \class QgsCheckableItemModel
+ * \ingroup gui
+ * QStandardItemModel subclass which makes all items checkable
+ * by default.
+ * \since QGIS 3.0
+ * \note not available in Python bindings
+ **/
+#ifndef SIP_RUN
+class QgsCheckableItemModel : public QStandardItemModel
+{
+    Q_OBJECT
+
+  public:
+
+    /** Constructor for QgsCheckableItemModel.
+     * \param parent parent object
+     */
+    QgsCheckableItemModel( QObject *parent = nullptr );
+
+    /** Returns a combination of the item flags: items are enabled
+     * (ItemIsEnabled), selectable (ItemIsSelectable) and checkable
+     * (ItemIsUserCheckable).
+     * \param index item index
+     */
+    virtual Qt::ItemFlags flags( const QModelIndex &index ) const;
+
+    /** Returns the data stored under the given role for the item
+     * referred to by the index.
+     * \param index item index
+     * \param role data role
+     */
+    virtual QVariant data( const QModelIndex &index, int role = Qt::DisplayRole ) const;
+
+    /** Sets the role data for the item at index to value.
+     * \param index item index
+     * \param value data value
+     * \param role data role
+     * \returns true on success, false otherwise
+     */
+    virtual bool setData( const QModelIndex &index, const QVariant &value, int role = Qt::EditRole );
+
+  signals:
+
+    /** This signal is emitted whenever the items checkstate has changed.
+     */
+    void itemCheckStateChanged();
+};
+
+
+/** \class QgsCheckBoxDelegate
+ * \ingroup gui
+ * QStyledItemDelegate subclass for QgsCheckableComboBox. Needed for
+ * correct drawing of the checkable items on Mac and GTK.
+ * \since QGIS 3.0
+ * \note not available in Python bindings
+ **/
+
+class QgsCheckBoxDelegate : public QStyledItemDelegate
+{
+    Q_OBJECT
+
+  public:
+
+    /** Constructor for QgsCheckBoxDelegate.
+     * \param parent parent object
+     */
+    QgsCheckBoxDelegate( QObject *parent = nullptr );
+
+    /** Renders the delegate using the given painter and style option
+     * for the item specified by index.
+     * \param painter painter to use
+     * \param option style option
+     * \param index item index
+     */
+    virtual void paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const;
+};
+#endif
+
+/** \class QgsCheckableComboBox
+ * \ingroup gui
+ * QComboBox subclass which allows selecting multiple items.
+ * \since QGIS 3.0
+ **/
+
+class GUI_EXPORT QgsCheckableComboBox : public QComboBox
+{
+    Q_OBJECT
+
+    Q_PROPERTY( QString separator READ separator WRITE setSeparator )
+    Q_PROPERTY( QString defaultText READ defaultText WRITE setDefaultText )
+    Q_PROPERTY( QStringList checkedItems READ checkedItems WRITE setCheckedItems )
+
+  public:
+
+    /** Constructor for QgsCheckableComboBox.
+     */
+    QgsCheckableComboBox( QWidget *parent SIP_TRANSFERTHIS = nullptr );
+
+    /** Returns separator used to separate items in the display text.
+     * \see setSeparator()
+     */
+    QString separator() const;
+
+    /** Set separator used to separate items in the display text.
+     * \param separator separator to use
+     * \see separator()
+     */
+    void setSeparator( const QString &separator );
+
+    /** Returns default text which will be displayed in the widget
+     * when no items selected.
+     * \see setDefaultText()
+     */
+    QString defaultText() const;
+
+    /** Set default text which will be displayed in the widget when
+     * no items selected.
+     * \param text default text
+     * \see defaultText()
+     */
+    void setDefaultText( const QString &text );
+
+    /** Returns currently checked items.
+     * \see setCheckedItems()
+     */
+    QStringList checkedItems() const;
+
+    /** Returns the checked state of the item identified by index
+     * \param index item index
+     * \see setItemCheckState()
+     * \see toggleItemCheckState()
+     */
+    Qt::CheckState itemCheckState( int index ) const;
+
+    /** Sets the item check state to state
+     * \param index item index
+     * \param state check state
+     * \see itemCheckState()
+     * \see toggleItemCheckState()
+     */
+    void setItemCheckState( int index, Qt::CheckState state );
+
+    /** Toggles the item check state
+     * \param index item index
+     * \see itemCheckState()
+     * \see setItemCheckState()
+     */
+    void toggleItemCheckState( int index );
+
+    /** Hides the list of items in the combobox if it is currently
+     * visible and resets the internal state.
+     */
+    virtual void hidePopup() override;
+
+    /** Filters events to enable context menu
+     */
+    virtual bool eventFilter( QObject *object, QEvent *event ) override;
+
+  signals:
+
+    /** This signal is emitted whenever the checked items list changed.
+     */
+    void checkedItemsChanged( const QStringList &items );
+
+  public slots:
+
+    /** Set items which should be checked/selected.
+     * \param items items to select
+     * \see checkedItems()
+     */
+    void setCheckedItems( const QStringList &items );
+
+  protected:
+
+    /** Handler for widget resizing
+     */
+    virtual void resizeEvent( QResizeEvent *event ) override;
+
+  protected slots:
+
+    /** Display context menu which allows to select/deselect
+     * all items at once.
+     */
+    void showContextMenu( const QPoint &pos );
+
+    /** Selects all items.
+     */
+    void selectAllOptions();
+
+    /** Removes selection from all items.
+     */
+    void deselectAllOptions();
+
+  private:
+    void updateCheckedItems();
+    void updateDisplayText();
+
+    QString mSeparator;
+    QString mDefaultText;
+
+    bool mSkipHide = false;
+
+    QMenu *mContextMenu = nullptr;
+    QAction *mSelectAllAction = nullptr;
+    QAction *mDeselectAllAction = nullptr;
+};
+
+#endif // QGSCHECKABLECOMBOBOX_H

tests/src/python/CMakeLists.txt

@@ -20,6 +20,7 @@ ADD_PYTHON_TEST(PyQgsAttributeTableModel test_qgsattributetablemodel.py)
 ADD_PYTHON_TEST(PyQgsBearingUtils test_qgsbearingutils.py)
 ADD_PYTHON_TEST(PyQgsBlendModes test_qgsblendmodes.py)
 ADD_PYTHON_TEST(PyQgsCategorizedSymbolRenderer test_qgscategorizedsymbolrenderer.py)
+ADD_PYTHON_TEST(PyQgsCheckableComboBox test_qgscheckablecombobox.py)
 ADD_PYTHON_TEST(PyQgsColorButton test_qgscolorbutton.py)
 ADD_PYTHON_TEST(PyQgsColorScheme test_qgscolorscheme.py)
 ADD_PYTHON_TEST(PyQgsColorSchemeRegistry test_qgscolorschemeregistry.py)

tests/src/python/test_qgscheckablecombobox.py

@@ -0,0 +1,63 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsCheckableComboBox
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+__author__ = 'Alexander Bruy'
+__date__ = '22/03/2017'
+__copyright__ = 'Copyright 2017, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+import qgis  # NOQA
+
+from qgis.PyQt.QtCore import Qt
+from qgis.PyQt.QtTest import QSignalSpy
+
+from qgis.gui import QgsCheckableComboBox
+from qgis.testing import start_app, unittest
+
+start_app()
+
+
+class TestQgsCheckableComboBox(unittest.TestCase):
+
+    def testGettersSetters(self):
+        """ test widget getters/setters """
+        w = qgis.gui.QgsCheckableComboBox()
+
+        w.setSeparator('|')
+        self.assertEqual(w.separator(), '|')
+        w.setDefaultText('Select items...')
+        self.assertEqual(w.defaultText(), 'Select items...')
+
+        w.addItems(['One', 'Two', 'Three'])
+
+        w.setCheckedItems(['Two'])
+        self.assertEqual(len(w.checkedItems()), 1)
+        self.assertEqual(w.checkedItems(), ['Two'])
+        w.setCheckedItems(['Three'])
+        self.assertEqual(len(w.checkedItems()), 2)
+        self.assertEqual(w.checkedItems(), ['Two', 'Three'])
+
+        w.setItemCheckState(2, Qt.Unchecked)
+        self.assertEqual(w.itemCheckState(2), Qt.Unchecked)
+
+    def test_ChangedSignals(self):
+        """ test that signals are correctly emitted when clearing"""
+
+        w = qgis.gui.QgsCheckableComboBox()
+
+        w.addItems(['One', 'Two', 'Three'])
+
+        checkedItemsChanged_spy = QSignalSpy(w.checkedItemsChanged)
+        w.setCheckedItems(['Two'])
+
+        self.assertEqual(len(checkedItemsChanged_spy), 1)
+
+
+if __name__ == '__main__':
+    unittest.main()