Combo Boxes in Item Views/de

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ComboBox in ItemView oder ItemWidget

Beispiel-Code, wie man ComboBoxen als Editor-Widget in einem ItemView oder ItemWidget benutzt

Das Delegate erzeugt eine ComboBox, falls der Index in der zweiten Spalte eines ListView ist. Bei allen anderen Spalten gibt es lediglich den Default-Editor zurück, der von QStyledItemDelegate erzeugt wird.

Datei itemdelegate.h

// —— File itemdelegate.h ——
#ifndef ITEMDELEGATE_H
#define ITEMDELEGATE_H

#include <QStyledItemDelegate>

class ComboBoxItemDelegate : public QStyledItemDelegate
{
 Q_OBJECT

public:
 ComboBoxItemDelegate(QObject *parent = 0);
 ~ComboBoxItemDelegate();

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

};

#endif // ITEMDELEGATE_H

Datei itemdelegate.cpp

// —— File itemdelegate.cpp ——
#include "itemdelegate.h"
#include <QComboBox>

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


ComboBoxItemDelegate::~ComboBoxItemDelegate()
{
}


QWidget *ComboBoxItemDelegate::createEditor( QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index ) const
{
 // ComboBox only in column 2
 if(index.column() != 1)
 return QStyledItemDelegate::createEditor(parent, option, index);

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

void ComboBoxItemDelegate::setModelData ( QWidget *editor, QAbstractItemModel *model, const QModelIndex &index ) const
{
 if(QComboBox *cb = qobject_cast<QComboBox*>(editor)) {
  // save the current text of the combo box as the current value of the item
  model->setData(index, cb->currentText(), Qt::EditRole);
 } else {
  QStyledItemDelegate::setModelData(editor, model, index);
 }
}

Datei main.cpp

// —— File main.cpp ——
#include <QApplication>
#include <QTableWidget>

#include "itemdelegate.h"

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

ComboBoxItemDelegate *cbid = new ComboBoxItemDelegate(&tw);
 tw.setItemDelegate(cbid);
 tw.setColumnCount(4);
 tw.setRowCount(10);
 tw.resize(600,400);
 tw.show();

return a.exec();
}