How to make QComboBox as MultiSelect in QT? - 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.

Answer 1

//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;
}

Answer 2

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.