Address Book example: Replace QPair by struct

Introduce Contact struct to store contact data and use it
instead of QPair<QString, QString>. Proper naming really
clarifies the code.

Task-number: QTBUG-60635
Change-Id: Ibfb421dfc854accc382212b0da46e7aafc0d528a
Reviewed-by: Jesus Fernandez <Jesus.Fernandez@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

3 files changed, 49 insertions, 37 deletions

diff --git a/examples/widgets/itemviews/addressbook/addresswidget.cpp b/examples/widgets/itemviews/addressbook/addresswidget.cpp
index cff35ad78f..9480d2ca8e 100644
--- a/examples/widgets/itemviews/addressbook/addresswidget.cpp
+++ b/examples/widgets/itemviews/addressbook/addresswidget.cpp
@@ -85,10 +85,7 @@ void AddressWidget::showAddEntryDialog()
 //! [3]
 void AddressWidget::addEntry(QString name, QString address)
 {
-    QList<QPair<QString, QString> >list = table->getList();
-    QPair<QString, QString> pair(name, address);
-
-    if (!list.contains(pair)) {
+    if (!table->getContacts().contains({ name, address })) {
         table->insertRows(0, 1, QModelIndex());
 
         QModelIndex index = table->index(0, 0, QModelIndex());
@@ -211,18 +208,16 @@ void AddressWidget::readFromFile(const QString &fileName)
         return;
     }
 
-    QList<QPair<QString, QString> > pairs = table->getList();
+    QList<Contact> contacts;
     QDataStream in(&file);
-    in >> pairs;
+    in >> contacts;
 
-    if (pairs.isEmpty()) {
+    if (contacts.isEmpty()) {
         QMessageBox::information(this, tr("No contacts in file"),
                                  tr("The file you are attempting to open contains no contacts."));
     } else {
-        for (int i=0; i<pairs.size(); ++i) {
-            QPair<QString, QString> p = pairs.at(i);
-            addEntry(p.first, p.second);
-        }
+        for (const auto &contact: qAsConst(contacts))
+            addEntry(contact.name, contact.address);
     }
 }
 //! [7]
@@ -237,8 +232,7 @@ void AddressWidget::writeToFile(const QString &fileName)
         return;
     }
 
-    QList<QPair<QString, QString> > pairs = table->getList();
     QDataStream out(&file);
-    out << pairs;
+    out << table->getContacts();
 }
 //! [6]
diff --git a/examples/widgets/itemviews/addressbook/tablemodel.cpp b/examples/widgets/itemviews/addressbook/tablemodel.cpp
index d701ef3223..674e312753 100644
--- a/examples/widgets/itemviews/addressbook/tablemodel.cpp
+++ b/examples/widgets/itemviews/addressbook/tablemodel.cpp
@@ -56,10 +56,10 @@ TableModel::TableModel(QObject *parent)
 {
 }
 
-TableModel::TableModel(QList<QPair<QString, QString> > pairs, QObject *parent)
+TableModel::TableModel(QList<Contact> contacts, QObject *parent)
     : QAbstractTableModel(parent)
+    , contacts(contacts)
 {
-    listOfPairs = pairs;
 }
 //! [0]
 
@@ -67,7 +67,7 @@ TableModel::TableModel(QList<QPair<QString, QString> > pairs, QObject *parent)
 int TableModel::rowCount(const QModelIndex &parent) const
 {
     Q_UNUSED(parent);
-    return listOfPairs.size();
+    return contacts.size();
 }
 
 int TableModel::columnCount(const QModelIndex &parent) const
@@ -83,16 +83,16 @@ QVariant TableModel::data(const QModelIndex &index, int role) const
     if (!index.isValid())
         return QVariant();
 
-    if (index.row() >= listOfPairs.size() || index.row() < 0)
+    if (index.row() >= contacts.size() || index.row() < 0)
         return QVariant();
 
     if (role == Qt::DisplayRole) {
-        QPair<QString, QString> pair = listOfPairs.at(index.row());
+        const auto &contact = contacts.at(index.row());
 
         if (index.column() == 0)
-            return pair.first;
+            return contact.name;
         else if (index.column() == 1)
-            return pair.second;
+            return contact.address;
     }
     return QVariant();
 }
@@ -126,10 +126,8 @@ bool TableModel::insertRows(int position, int rows, const QModelIndex &index)
     Q_UNUSED(index);
     beginInsertRows(QModelIndex(), position, position + rows - 1);
 
-    for (int row = 0; row < rows; ++row) {
-        QPair<QString, QString> pair(" ", " ");
-        listOfPairs.insert(position, pair);
-    }
+    for (int row = 0; row < rows; ++row)
+        contacts.insert(position, { QString(), QString() });
 
     endInsertRows();
     return true;
@@ -142,9 +140,8 @@ bool TableModel::removeRows(int position, int rows, const QModelIndex &index)
     Q_UNUSED(index);
     beginRemoveRows(QModelIndex(), position, position + rows - 1);
 
-    for (int row = 0; row < rows; ++row) {
-        listOfPairs.removeAt(position);
-    }
+    for (int row = 0; row < rows; ++row)
+        contacts.removeAt(position);
 
     endRemoveRows();
     return true;
@@ -157,16 +154,16 @@ bool TableModel::setData(const QModelIndex &index, const QVariant &value, int ro
     if (index.isValid() && role == Qt::EditRole) {
         int row = index.row();
 
-        QPair<QString, QString> p = listOfPairs.value(row);
+        auto contact = contacts.value(row);
 
         if (index.column() == 0)
-            p.first = value.toString();
+            contact.name = value.toString();
         else if (index.column() == 1)
-            p.second = value.toString();
+            contact.address = value.toString();
         else
             return false;
 
-        listOfPairs.replace(row, p);
+        contacts.replace(row, contact);
         emit(dataChanged(index, index));
 
         return true;
@@ -187,8 +184,8 @@ Qt::ItemFlags TableModel::flags(const QModelIndex &index) const
 //! [7]
 
 //! [8]
-QList< QPair<QString, QString> > TableModel::getList()
+QList<Contact> TableModel::getContacts() const
 {
-    return listOfPairs;
+    return contacts;
 }
 //! [8]
diff --git a/examples/widgets/itemviews/addressbook/tablemodel.h b/examples/widgets/itemviews/addressbook/tablemodel.h
index 9a669c508d..1004a35d31 100644
--- a/examples/widgets/itemviews/addressbook/tablemodel.h
+++ b/examples/widgets/itemviews/addressbook/tablemodel.h
@@ -53,16 +53,37 @@
 
 #include <QAbstractTableModel>
 #include <QList>
-#include <QPair>
 
 //! [0]
+
+struct Contact
+{
+    QString name;
+    QString address;
+
+    bool operator==(const Contact &other) const
+    {
+        return name == other.name && address == other.address;
+    }
+};
+
+inline QDataStream &operator<<(QDataStream &stream, const Contact &contact)
+{
+    return stream << contact.name << contact.address;
+}
+
+inline QDataStream &operator>>(QDataStream &stream, Contact &contact)
+{
+    return stream >> contact.name >> contact.address;
+}
+
 class TableModel : public QAbstractTableModel
 {
     Q_OBJECT
 
 public:
     TableModel(QObject *parent = 0);
-    TableModel(QList<QPair<QString, QString> > listofPairs, QObject *parent = 0);
+    TableModel(QList<Contact> contacts, QObject *parent = 0);
 
     int rowCount(const QModelIndex &parent) const override;
     int columnCount(const QModelIndex &parent) const override;
@@ -72,10 +93,10 @@ public:
     bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
     bool insertRows(int position, int rows, const QModelIndex &index = QModelIndex()) override;
     bool removeRows(int position, int rows, const QModelIndex &index = QModelIndex()) override;
-    QList<QPair<QString, QString> > getList();
+    QList<Contact> getContacts() const;
 
 private:
-    QList<QPair<QString, QString> > listOfPairs;
+    QList<Contact> contacts;
 };
 //! [0]