#include <QtWidgets>
 #include "window.h"
 Window::Window(QWidget *parent)
     : QWidget(parent)
 {
     setupModel();
     nameLabel = new QLabel(tr("Na&me:"));
     nameEdit = new QLineEdit();
     addressLabel = new QLabel(tr("&Address:"));
     addressEdit = new QTextEdit();
     typeLabel = new QLabel(tr("&Type:"));
     typeComboBox = new QComboBox();
     nextButton = new QPushButton(tr("&Next"));
     previousButton = new QPushButton(tr("&Previous"));
     nameLabel->setBuddy(nameEdit);
     addressLabel->setBuddy(addressEdit);
     typeLabel->setBuddy(typeComboBox);
     typeComboBox->setModel(typeModel);
     mapper = new QDataWidgetMapper(this);
     mapper->setModel(model);
     mapper->addMapping(nameEdit, 0);
     mapper->addMapping(addressEdit, 1);
     mapper->addMapping(typeComboBox, 2, "currentIndex");
     connect(previousButton, SIGNAL(clicked()),
             mapper, SLOT(toPrevious()));
     connect(nextButton, SIGNAL(clicked()),
             mapper, SLOT(toNext()));
     connect(mapper, SIGNAL(currentIndexChanged(int)),
             this, SLOT(updateButtons(int)));
     QGridLayout *layout = new QGridLayout();
     layout->addWidget(nameLabel, 0, 0, 1, 1);
     layout->addWidget(nameEdit, 0, 1, 1, 1);
     layout->addWidget(previousButton, 0, 2, 1, 1);
     layout->addWidget(addressLabel, 1, 0, 1, 1);
     layout->addWidget(addressEdit, 1, 1, 2, 1);
     layout->addWidget(nextButton, 1, 2, 1, 1);
     layout->addWidget(typeLabel, 3, 0, 1, 1);
     layout->addWidget(typeComboBox, 3, 1, 1, 1);
     setLayout(layout);
     setWindowTitle(tr("Delegate Widget Mapper"));
     mapper->toFirst();
 }
 void Window::setupModel()
 {
     QStringList items;
     items << tr("Home") << tr("Work") << tr("Other");
     typeModel = new QStringListModel(items, this);
     model = new QStandardItemModel(5, 3, this);
     QStringList names;
     names << "Alice" << "Bob" << "Carol" << "Donald" << "Emma";
     QStringList addresses;
     addresses << "<qt>123 Main Street<br/>Market Town</qt>"
               << "<qt>PO Box 32<br/>Mail Handling Service"
                  "<br/>Service City</qt>"
               << "<qt>The Lighthouse<br/>Remote Island</qt>"
               << "<qt>47338 Park Avenue<br/>Big City</qt>"
               << "<qt>Research Station<br/>Base Camp<br/>Big Mountain</qt>";
     QStringList types;
     types << "0" << "1" << "2" << "0" << "2";
     for (int row = 0; row < 5; ++row) {
       QStandardItem *item = new QStandardItem(names[row]);
       model->setItem(row, 0, item);
       item = new QStandardItem(addresses[row]);
       model->setItem(row, 1, item);
       item = new QStandardItem(types[row]);
       model->setItem(row, 2, item);
     }
 }
 void Window::updateButtons(int row)
 {
     previousButton->setEnabled(row > 0);
     nextButton->setEnabled(row < model->rowCount() - 1);
 }