Difference between revisions of "Combo Boxes in Item Views"

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{{Cleanup | reason=Auto-imported from ExpressionEngine.}}
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{{LangSwitch}}
 
 
 
[[Category:Snippets]]
 
[[Category:Snippets]]
 
'''English''' | [[Combo_Boxes_in_Item_Views_German|Deutsch]]
 
 
= Combo Boxes in Item Views =
 
 
 
Sample code to use combo boxes as editor widgets in an item view or item widget.
 
Sample code to use combo boxes as editor widgets in an item view or item widget.
  
The delegate creates a combo box if the index is in the second column of a list view. For the other columns it just returns the default editor, that [http://doc.qt.io/qt-5.0/qtwidgets/qstyleditemdelegate.html QStyledItemDelegate] creates.
+
The delegate creates a combo box if the index is in the second column of a list view. For the other columns it just returns the default editor, that {{DocLink|QStyledItemDelegate}} creates.
  
File itemdelegate.h
+
File comboboxitemdelegate.h
  
 
<code>
 
<code>
// —— File itemdelegate.h ——
+
#ifndef COMBOBOXITEMDELEGATE_H
#ifndef ITEMDELEGATE_H
+
#define COMBOBOXITEMDELEGATE_H
#define ITEMDELEGATE_H
 
  
 
#include <QStyledItemDelegate>
 
#include <QStyledItemDelegate>
Line 22: Line 15:
 
class ComboBoxItemDelegate : public QStyledItemDelegate
 
class ComboBoxItemDelegate : public QStyledItemDelegate
 
{
 
{
Q_OBJECT
+
    Q_OBJECT
 
 
 
public:
 
public:
ComboBoxItemDelegate(QObject *parent = 0);
+
    ComboBoxItemDelegate(QObject *parent = nullptr);
~ComboBoxItemDelegate();
+
    ~ComboBoxItemDelegate();
 
 
virtual QWidget *createEditor( QWidget *parent, const QStyleOptionViewItem &amp;option, const QModelIndex &amp;index ) const;
 
virtual void setEditorData ( QWidget *editor, const QModelIndex &amp;index ) const;
 
virtual void setModelData ( QWidget *editor, QAbstractItemModel *model, const QModelIndex &amp;index ) const;
 
  
 +
    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
 +
    void setEditorData(QWidget *editor, const QModelIndex &index) const override;
 +
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override;
 
};
 
};
  
#endif // ITEMDELEGATE_H
+
#endif // COMBOBOXITEMDELEGATE_H
 
</code>
 
</code>
  
File itemdelegate.cpp
+
File comboboxitemdelegate.cpp
  
 
<code>
 
<code>
// —— File itemdelegate.cpp ——
+
#include "comboboxitemdelegate.h"
#include "itemdelegate.h"
 
 
#include <QComboBox>
 
#include <QComboBox>
  
ComboBoxItemDelegate::ComboBoxItemDelegate(QObject '''parent)
+
ComboBoxItemDelegate::ComboBoxItemDelegate(QObject *parent)
: QStyledItemDelegate(parent)
+
    : QStyledItemDelegate(parent)
 
{
 
{
 
}
 
}
Line 55: Line 45:
  
  
QWidget''' ComboBoxItemDelegate::createEditor( QWidget *parent, const QStyleOptionViewItem &amp;option, const QModelIndex &amp;index ) const
+
QWidget *ComboBoxItemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
 
{
 
{
// ComboBox ony in column 2
+
    // Create the combobox and populate it
if(index.column() != 1)
+
    QComboBox *cb = new QComboBox(parent);
return QStyledItemDelegate::createEditor(parent, option, index);
+
    const int row = index.row();
 +
    cb->addItem(QString("one in row %1").arg(row));
 +
    cb->addItem(QString("two in row %1").arg(row));
 +
    cb->addItem(QString("three in row %1").arg(row));
 +
    return cb;
 +
}
  
// Create the combobox and populate it
 
QComboBox *cb = new QComboBox(parent);
 
int row = index.row();
 
cb->addItem(QString("one in row %1").arg(row));
 
cb->addItem(QString("two in row %1").arg(row));
 
cb->addItem(QString("three in row %1").arg(row));
 
return cb;
 
}
 
  
void ComboBoxItemDelegate::setEditorData ( QWidget *editor, const QModelIndex &amp;index ) const
+
void ComboBoxItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
 
{
 
{
if(QComboBox '''cb = qobject_cast<QComboBox'''>(editor)) {
+
    QComboBox *cb = qobject_cast<QComboBox *>(editor);
// get the index of the text in the combobox that matches the current value of the itenm
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    Q_ASSERT(cb);
QString currentText = index.data(Qt::EditRole).toString();
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    // get the index of the text in the combobox that matches the current value of the item
int cbIndex = cb->findText(currentText);
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    const QString currentText = index.data(Qt::EditRole).toString();
// if it is valid, adjust the combobox
+
    const int cbIndex = cb->findText(currentText);
if(cbIndex >= 0)
+
    // if it is valid, adjust the combobox
cb->setCurrentIndex(cbIndex);
+
    if (cbIndex >= 0)
} else {
+
      cb->setCurrentIndex(cbIndex);
QStyledItemDelegate::setEditorData(editor, index);
 
}
 
 
}
 
}
  
void ComboBoxItemDelegate::setModelData ( QWidget *editor, QAbstractItemModel *model, const QModelIndex &amp;index ) const
+
 
 +
void ComboBoxItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
 
{
 
{
if(QComboBox '''cb = qobject_cast<QComboBox'''>(editor))
+
    QComboBox *cb = qobject_cast<QComboBox *>(editor);
// save the current text of the combo box as the current value of the item
+
    Q_ASSERT(cb);
model->setData(index, cb->currentText(), Qt::EditRole);
+
    model->setData(index, cb->currentText(), Qt::EditRole);
else
 
QStyledItemDelegate::setModelData(editor, model, index);
 
 
}
 
}
 
</code>
 
</code>
 +
  
 
File main.cpp
 
File main.cpp
  
 
<code>
 
<code>
// —— File main.cpp ——
 
 
#include <QApplication>
 
#include <QApplication>
 
#include <QTableWidget>
 
#include <QTableWidget>
  
#include "itemdelegate.h"
+
#include "comboboxitemdelegate.h"
  
 
int main(int argc, char *argv[])
 
int main(int argc, char *argv[])
 
{
 
{
QApplication a(argc, argv);
+
    QApplication a(argc, argv);
QTableWidget tw;
+
    QTableWidget tw;
  
ComboBoxItemDelegate *cbid = new ComboBoxItemDelegate(&amp;tw);
+
    ComboBoxItemDelegate* cbid = new ComboBoxItemDelegate(&tw);
tw.setItemDelegate(cbid);
+
    // ComboBox only in column 2
tw.setColumnCount(4);
+
    tw.setItemDelegateForColumn(1, cbid);
tw.setRowCount(10);
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    tw.setColumnCount(4);
tw.resize(600,400);
+
    tw.setRowCount(10);
tw.show();
+
    tw.resize(600,400);
 +
    tw.show();
  
return a.exec();
+
    return a.exec();
 
}
 
}
 +
</code>

Latest revision as of 13:13, 5 February 2019

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Sample code to use combo boxes as editor widgets in an item view or item widget.

The delegate creates a combo box if the index is in the second column of a list view. For the other columns it just returns the default editor, that QStyledItemDelegate creates.

File comboboxitemdelegate.h

#ifndef COMBOBOXITEMDELEGATE_H
#define COMBOBOXITEMDELEGATE_H

#include <QStyledItemDelegate>

class ComboBoxItemDelegate : public QStyledItemDelegate
{
    Q_OBJECT
public:
    ComboBoxItemDelegate(QObject *parent = nullptr);
    ~ComboBoxItemDelegate();

    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
    void setEditorData(QWidget *editor, const QModelIndex &index) const override;
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override;
};

#endif // COMBOBOXITEMDELEGATE_H

File comboboxitemdelegate.cpp

#include "comboboxitemdelegate.h"
#include <QComboBox>

ComboBoxItemDelegate::ComboBoxItemDelegate(QObject *parent)
    : QStyledItemDelegate(parent)
{
}


ComboBoxItemDelegate::~ComboBoxItemDelegate()
{
}


QWidget *ComboBoxItemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    // Create the combobox and populate it
    QComboBox *cb = new QComboBox(parent);
    const int row = index.row();
    cb->addItem(QString("one in row %1").arg(row));
    cb->addItem(QString("two in row %1").arg(row));
    cb->addItem(QString("three in row %1").arg(row));
    return cb;
}


void ComboBoxItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
    QComboBox *cb = qobject_cast<QComboBox *>(editor);
    Q_ASSERT(cb);
    // get the index of the text in the combobox that matches the current value of the item
    const QString currentText = index.data(Qt::EditRole).toString();
    const int cbIndex = cb->findText(currentText);
    // if it is valid, adjust the combobox
    if (cbIndex >= 0)
       cb->setCurrentIndex(cbIndex);
}


void ComboBoxItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
    QComboBox *cb = qobject_cast<QComboBox *>(editor);
    Q_ASSERT(cb);
    model->setData(index, cb->currentText(), Qt::EditRole);
}


File main.cpp

#include <QApplication>
#include <QTableWidget>

#include "comboboxitemdelegate.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QTableWidget tw;

    ComboBoxItemDelegate* cbid = new ComboBoxItemDelegate(&tw);
    // ComboBox only in column 2 
    tw.setItemDelegateForColumn(1, cbid);
    tw.setColumnCount(4);
    tw.setRowCount(10);
    tw.resize(600,400);
    tw.show();

    return a.exec();
}