How to make QComboBox as MultiSelect in QT?

Question

How to make QComboBox as MultiSelect in QT ?

There is no option of MultiSelect in Combox in QT ?

OR

Anybody can suggest me some diffrent control but look & feel should be like QCombobox only.

score 2 · Accepted Answer · edited Jul 02 '11 at 03:46

//This is the file named as CheckBoxList.h

#ifndef CHECKBOXLIST_H
#define CHECKBOXLIST_H

#include <QtGui>

class CheckBoxList: public QComboBox
{
    Q_OBJECT;

public:
    CheckBoxList(QWidget *widget = 0);
    virtual ~CheckBoxList();
    bool eventFilter(QObject *object, QEvent *event);
    virtual void paintEvent(QPaintEvent *);
    void SetDisplayText(QString text);
    QString GetDisplayText() const;

private:
    QString m_DisplayText;
};

#endif // CHECKBOXLIST_H

//This is the file named as CheckBoxList.cpp

#include "CheckBoxList.h"
#include <QtGui>

// internal private delegate
class CheckBoxListDelegate : public QItemDelegate
{
public:

    CheckBoxListDelegate(QObject *parent)
         : QItemDelegate(parent)
    {
        ;
    }

    void paint(QPainter *painter, const QStyleOptionViewItem &option,
                          const QModelIndex &index) const
    {
        //Get item data
        bool value = index.data(Qt::UserRole).toBool();
        QString text = index.data(Qt::DisplayRole).toString();

        // fill style options with item data
        const QStyle *style = QApplication::style();
        QStyleOptionButton opt;
        opt.state |= value ? QStyle::State_On : QStyle::State_Off;
        opt.state |= QStyle::State_Enabled;
        opt.text = text;
        opt.rect = option.rect;

        // draw item data as CheckBox
        style->drawControl(QStyle::CE_CheckBox,&opt,painter);
//QMessageBox::information(0,"Info",text);

    }

        QWidget *createEditor(QWidget *parent,
         const QStyleOptionViewItem & option ,
         const QModelIndex & index ) const
    {
        // create check box as our editor

         QCheckBox *editor = new QCheckBox(parent);

         return editor;
    }

     void setEditorData(QWidget *editor,
                                         const QModelIndex &index) const
     {

         //set editor data
         QCheckBox *myEditor = static_cast<QCheckBox*>(editor);
         myEditor->setText(index.data(Qt::DisplayRole).toString());
         myEditor->setChecked(index.data(Qt::UserRole).toBool());

//
     }

     void setModelData(QWidget *editor, QAbstractItemModel *model,
                                        const QModelIndex &index) const
     {
         //get the value from the editor (CheckBox)
         QCheckBox *myEditor = static_cast<QCheckBox*>(editor);
         bool value = myEditor->isChecked();


         //set model data
         QMap<int,QVariant> data;
         data.insert(Qt::DisplayRole,myEditor->text());
         data.insert(Qt::UserRole,value);
         model->setItemData(index,data);

     }

     void updateEditorGeometry(QWidget *editor,
         const QStyleOptionViewItem &option, const QModelIndex &index ) const
     {

         editor->setGeometry(option.rect);


     }
 };     
//min-width:10em; 
     CheckBoxList::CheckBoxList(QWidget *widget )
     :QComboBox(widget),m_DisplayText(0)
     {
    // set delegate items view 
    view()->setItemDelegate(new CheckBoxListDelegate(this));
    //view()->setStyleSheet("  padding: 15px; ");
    // Enable editing on items view
    view()->setEditTriggers(QAbstractItemView::CurrentChanged);

    // set "CheckBoxList::eventFilter" as event filter for items view 
    view()->viewport()->installEventFilter(this);


    // it just cool to have it as defualt ;)
    view()->setAlternatingRowColors(true);
     }


CheckBoxList::~CheckBoxList()
{
    ;
}
bool CheckBoxList::eventFilter(QObject *object, QEvent *event)
{
    // don't close items view after we release the mouse button
    // by simple eating MouseButtonRelease in viewport of items view
    if(event->type() == QEvent::MouseButtonRelease && object==view()->viewport()) 
    {
        return true;
    }
    return QComboBox::eventFilter(object,event);
}
void CheckBoxList::paintEvent(QPaintEvent *)
{
    QStylePainter painter(this);
    painter.setPen(palette().color(QPalette::Text));

    // draw the combobox frame, focusrect and selected etc.
    QStyleOptionComboBox opt;
    initStyleOption(&opt);

    // if no display text been set , use "..." as default
    if(m_DisplayText.isNull())
        opt.currentText = "......";
    else
        opt.currentText = m_DisplayText;
    painter.drawComplexControl(QStyle::CC_ComboBox, opt);

    // draw the icon and text
    painter.drawControl(QStyle::CE_ComboBoxLabel, opt);

}


void CheckBoxList::SetDisplayText(QString text)
{
    m_DisplayText = text;

}

QString CheckBoxList::GetDisplayText() const
{
    return m_DisplayText;
}

How do you know which checkboxes are selected so you can generate the display text? — CompEng88, Dec 10 '15 at 21:11
Seems like your code has an issue when there is only 1 checkbox in the view. It seems to ignore the mouse clicks and doesn't check. I assume it as to do with the eventFilter in your combobox. Any fixes? — CompEng88, Dec 18 '15 at 23:11
Deriving this class from a `QComboBox` is a mistake, since you cannot properly override functionality that isn't relevant anymore, due to the functions in question not being `virtual`. — Daniel Kamil Kozar, Dec 28 '16 at 08:55

score 0 · Answer 2 · edited May 23 '17 at 11:46

0

One alternative is to set menu with checkable actions to a button, as I've shown here.
Or you can change the selection model of the combo and control the hiding and showing of the pop up window as shown here.

edited May 23 '17 at 11:46

Community

1
1

answered Jun 28 '11 at 11:39

zkunov

3,362
1
20
17

How to make QComboBox as MultiSelect in QT?

2 Answers2