Cleanup EditableItemModel example

Cleanup the EditableItemModel example:
 - include own headers first
 - use nullptr
 - add sanity checks
 - use for loop instead foreach
 - use const where possible

Change-Id: Ib36e5710c07979576b48a905ee50908a64dcb697
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

examples/widgets/itemviews/editabletreemodel/main.cpp

@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
-
 #include "mainwindow.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(editabletreemodel);

examples/widgets/itemviews/editabletreemodel/mainwindow.cpp

@@ -58,8 +58,7 @@ MainWindow::MainWindow(QWidget *parent)
 {
     setupUi(this);
 
-    QStringList headers;
-    headers << tr("Title") << tr("Description");
+    const QStringList headers({tr("Title"), tr("Description")});
 
     QFile file(":/default.txt");
     file.open(QIODevice::ReadOnly);
@@ -87,7 +86,7 @@ MainWindow::MainWindow(QWidget *parent)
 
 void MainWindow::insertChild()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
 
     if (model->columnCount(index) == 0) {
@@ -99,10 +98,10 @@ void MainWindow::insertChild()
         return;
 
     for (int column = 0; column < model->columnCount(index); ++column) {
-        QModelIndex child = model->index(0, column, index);
-        model->setData(child, QVariant("[No data]"), Qt::EditRole);
+        const QModelIndex child = model->index(0, column, index);
+        model->setData(child, QVariant(tr("[No data]")), Qt::EditRole);
         if (!model->headerData(column, Qt::Horizontal).isValid())
-            model->setHeaderData(column, Qt::Horizontal, QVariant("[No header]"), Qt::EditRole);
+            model->setHeaderData(column, Qt::Horizontal, QVariant(tr("[No header]")), Qt::EditRole);
     }
 
     view->selectionModel()->setCurrentIndex(model->index(0, 0, index),
@@ -127,7 +126,7 @@ bool MainWindow::insertColumn()
 
 void MainWindow::insertRow()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
 
     if (!model->insertRow(index.row()+1, index.parent()))
@@ -136,19 +135,18 @@ void MainWindow::insertRow()
     updateActions();
 
     for (int column = 0; column < model->columnCount(index.parent()); ++column) {
-        QModelIndex child = model->index(index.row()+1, column, index.parent());
-        model->setData(child, QVariant("[No data]"), Qt::EditRole);
+        const QModelIndex child = model->index(index.row() + 1, column, index.parent());
+        model->setData(child, QVariant(tr("[No data]")), Qt::EditRole);
     }
 }
 
 bool MainWindow::removeColumn()
 {
     QAbstractItemModel *model = view->model();
-    int column = view->selectionModel()->currentIndex().column();
+    const int column = view->selectionModel()->currentIndex().column();
 
     // Insert columns in each child of the parent item.
-    bool changed = model->removeColumn(column);
-
+    const bool changed = model->removeColumn(column);
     if (changed)
         updateActions();
 
@@ -157,7 +155,7 @@ bool MainWindow::removeColumn()
 
 void MainWindow::removeRow()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
     if (model->removeRow(index.row(), index.parent()))
         updateActions();
@@ -165,19 +163,19 @@ void MainWindow::removeRow()
 
 void MainWindow::updateActions()
 {
-    bool hasSelection = !view->selectionModel()->selection().isEmpty();
+    const bool hasSelection = !view->selectionModel()->selection().isEmpty();
     removeRowAction->setEnabled(hasSelection);
     removeColumnAction->setEnabled(hasSelection);
 
-    bool hasCurrent = view->selectionModel()->currentIndex().isValid();
+    const bool hasCurrent = view->selectionModel()->currentIndex().isValid();
     insertRowAction->setEnabled(hasCurrent);
     insertColumnAction->setEnabled(hasCurrent);
 
     if (hasCurrent) {
         view->closePersistentEditor(view->selectionModel()->currentIndex());
 
-        int row = view->selectionModel()->currentIndex().row();
-        int column = view->selectionModel()->currentIndex().column();
+        const int row = view->selectionModel()->currentIndex().row();
+        const int column = view->selectionModel()->currentIndex().column();
         if (view->selectionModel()->currentIndex().parent().isValid())
             statusBar()->showMessage(tr("Position: (%1,%2)").arg(row).arg(column));
         else

examples/widgets/itemviews/editabletreemodel/mainwindow.h

@@ -54,14 +54,13 @@
 #include "ui_mainwindow.h"
 
 #include <QMainWindow>
-#include <QModelIndex>
 
 class MainWindow : public QMainWindow, private Ui::MainWindow
 {
     Q_OBJECT
 
 public:
-    MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = nullptr);
 
 public slots:
     void updateActions();

examples/widgets/itemviews/editabletreemodel/treeitem.cpp

@@ -56,14 +56,11 @@
 
 #include "treeitem.h"
 
-#include <QStringList>
-
 //! [0]
 TreeItem::TreeItem(const QVector<QVariant> &data, TreeItem *parent)
-{
-    parentItem = parent;
-    itemData = data;
-}
+    : itemData(data),
+      parentItem(parent)
+{}
 //! [0]
 
 //! [1]
@@ -76,7 +73,9 @@ TreeItem::~TreeItem()
 //! [2]
 TreeItem *TreeItem::child(int number)
 {
-    return childItems.value(number);
+    if (number < 0 || number >= childItems.size())
+        return nullptr;
+    return childItems.at(number);
 }
 //! [2]
 
@@ -92,7 +91,6 @@ int TreeItem::childNumber() const
 {
     if (parentItem)
         return parentItem->childItems.indexOf(const_cast<TreeItem*>(this));
-
     return 0;
 }
 //! [4]
@@ -107,7 +105,9 @@ int TreeItem::columnCount() const
 //! [6]
 QVariant TreeItem::data(int column) const
 {
-    return itemData.value(column);
+    if (column < 0 || column >= itemData.size())
+        return QVariant();
+    return itemData.at(column);
 }
 //! [6]
 
@@ -136,7 +136,7 @@ bool TreeItem::insertColumns(int position, int columns)
     for (int column = 0; column < columns; ++column)
         itemData.insert(position, QVariant());
 
-    foreach (TreeItem *child, childItems)
+    for (TreeItem *child : qAsConst(childItems))
         child->insertColumns(position, columns);
 
     return true;
@@ -171,7 +171,7 @@ bool TreeItem::removeColumns(int position, int columns)
     for (int column = 0; column < columns; ++column)
         itemData.remove(position);
 
-    foreach (TreeItem *child, childItems)
+    for (TreeItem *child : qAsConst(childItems))
         child->removeColumns(position, columns);
 
     return true;

examples/widgets/itemviews/editabletreemodel/treeitem.h

@@ -51,7 +51,6 @@
 #ifndef TREEITEM_H
 #define TREEITEM_H
 
-#include <QList>
 #include <QVariant>
 #include <QVector>
 
@@ -59,7 +58,7 @@
 class TreeItem
 {
 public:
-    explicit TreeItem(const QVector<QVariant> &data, TreeItem *parent = 0);
+    explicit TreeItem(const QVector<QVariant> &data, TreeItem *parent = nullptr);
     ~TreeItem();
 
     TreeItem *child(int number);
@@ -75,7 +74,7 @@ public:
     bool setData(int column, const QVariant &value);
 
 private:
-    QList<TreeItem*> childItems;
+    QVector<TreeItem*> childItems;
     QVector<QVariant> itemData;
     TreeItem *parentItem;
 };

examples/widgets/itemviews/editabletreemodel/treemodel.cpp

@@ -48,21 +48,21 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include "treeitem.h"
 #include "treemodel.h"
+#include "treeitem.h"
+
+#include <QtWidgets>
 
 //! [0]
 TreeModel::TreeModel(const QStringList &headers, const QString &data, QObject *parent)
     : QAbstractItemModel(parent)
 {
     QVector<QVariant> rootData;
-    foreach (QString header, headers)
+    for (const QString &header : headers)
         rootData << header;
 
     rootItem = new TreeItem(rootData);
-    setupModelData(data.split(QString("\n")), rootItem);
+    setupModelData(data.split('\n'), rootItem);
 }
 //! [0]
 
@@ -74,8 +74,9 @@ TreeModel::~TreeModel()
 //! [1]
 
 //! [2]
-int TreeModel::columnCount(const QModelIndex & /* parent */) const
+int TreeModel::columnCount(const QModelIndex &parent) const
 {
+    Q_UNUSED(parent);
     return rootItem->columnCount();
 }
 //! [2]
@@ -97,7 +98,7 @@ QVariant TreeModel::data(const QModelIndex &index, int role) const
 Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return 0;
+        return Qt::NoItemFlags;
 
     return Qt::ItemIsEditable | QAbstractItemModel::flags(index);
 }
@@ -133,21 +134,20 @@ QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) con
 
 //! [6]
     TreeItem *parentItem = getItem(parent);
+    if (!parentItem)
+        return QModelIndex();
 
     TreeItem *childItem = parentItem->child(row);
     if (childItem)
         return createIndex(row, column, childItem);
-    else
-        return QModelIndex();
+    return QModelIndex();
 }
 //! [6]
 
 bool TreeModel::insertColumns(int position, int columns, const QModelIndex &parent)
 {
-    bool success;
-
     beginInsertColumns(parent, position, position + columns - 1);
-    success = rootItem->insertColumns(position, columns);
+    const bool success = rootItem->insertColumns(position, columns);
     endInsertColumns();
 
     return success;
@@ -156,10 +156,13 @@ bool TreeModel::insertColumns(int position, int columns, const QModelIndex &pare
 bool TreeModel::insertRows(int position, int rows, const QModelIndex &parent)
 {
     TreeItem *parentItem = getItem(parent);
-    bool success;
+    if (!parentItem)
+        return false;
 
     beginInsertRows(parent, position, position + rows - 1);
-    success = parentItem->insertChildren(position, rows, rootItem->columnCount());
+    const bool success = parentItem->insertChildren(position,
+                                                    rows,
+                                                    rootItem->columnCount());
     endInsertRows();
 
     return success;
@@ -172,9 +175,9 @@ QModelIndex TreeModel::parent(const QModelIndex &index) const
         return QModelIndex();
 
     TreeItem *childItem = getItem(index);
-    TreeItem *parentItem = childItem->parent();
+    TreeItem *parentItem = childItem ? childItem->parent() : nullptr;
 
-    if (parentItem == rootItem)
+    if (parentItem == rootItem || !parentItem)
         return QModelIndex();
 
     return createIndex(parentItem->childNumber(), 0, parentItem);
@@ -183,10 +186,8 @@ QModelIndex TreeModel::parent(const QModelIndex &index) const
 
 bool TreeModel::removeColumns(int position, int columns, const QModelIndex &parent)
 {
-    bool success;
-
     beginRemoveColumns(parent, position, position + columns - 1);
-    success = rootItem->removeColumns(position, columns);
+    const bool success = rootItem->removeColumns(position, columns);
     endRemoveColumns();
 
     if (rootItem->columnCount() == 0)
@@ -198,10 +199,11 @@ bool TreeModel::removeColumns(int position, int columns, const QModelIndex &pare
 bool TreeModel::removeRows(int position, int rows, const QModelIndex &parent)
 {
     TreeItem *parentItem = getItem(parent);
-    bool success = true;
+    if (!parentItem)
+        return false;
 
     beginRemoveRows(parent, position, position + rows - 1);
-    success = parentItem->removeChildren(position, rows);
+    const bool success = parentItem->removeChildren(position, rows);
     endRemoveRows();
 
     return success;
@@ -210,9 +212,9 @@ bool TreeModel::removeRows(int position, int rows, const QModelIndex &parent)
 //! [8]
 int TreeModel::rowCount(const QModelIndex &parent) const
 {
-    TreeItem *parentItem = getItem(parent);
+    const TreeItem *parentItem = getItem(parent);
 
-    return parentItem->childCount();
+    return parentItem ? parentItem->childCount() : 0;
 }
 //! [8]
 
@@ -225,7 +227,7 @@ bool TreeModel::setData(const QModelIndex &index, const QVariant &value, int rol
     bool result = item->setData(index.column(), value);
 
     if (result)
-        emit dataChanged(index, index, {role});
+        emit dataChanged(index, index, {Qt::DisplayRole, Qt::EditRole});
 
     return result;
 }
@@ -236,7 +238,7 @@ bool TreeModel::setHeaderData(int section, Qt::Orientation orientation,
     if (role != Qt::EditRole || orientation != Qt::Horizontal)
         return false;
 
-    bool result = rootItem->setData(section, value);
+    const bool result = rootItem->setData(section, value);
 
     if (result)
         emit headerDataChanged(orientation, section, section);
@@ -246,8 +248,8 @@ bool TreeModel::setHeaderData(int section, Qt::Orientation orientation,
 
 void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
 {
-    QList<TreeItem*> parents;
-    QList<int> indentations;
+    QVector<TreeItem*> parents;
+    QVector<int> indentations;
     parents << parent;
     indentations << 0;
 
@@ -261,14 +263,15 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             ++position;
         }
 
-        QString lineData = lines[number].mid(position).trimmed();
+        const QString lineData = lines[number].mid(position).trimmed();
 
         if (!lineData.isEmpty()) {
             // Read the column data from the rest of the line.
-            QStringList columnStrings = lineData.split("\t", QString::SkipEmptyParts);
+            const QStringList columnStrings = lineData.split('\t', QString::SkipEmptyParts);
             QVector<QVariant> columnData;
-            for (int column = 0; column < columnStrings.count(); ++column)
-                columnData << columnStrings[column];
+            columnData.reserve(columnStrings.size());
+            for (const QString &columnString : columnStrings)
+                columnData << columnString;
 
             if (position > indentations.last()) {
                 // The last child of the current parent is now the new parent
@@ -291,7 +294,6 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             for (int column = 0; column < columnData.size(); ++column)
                 parent->child(parent->childCount() - 1)->setData(column, columnData[column]);
         }
-
         ++number;
     }
 }

examples/widgets/itemviews/editabletreemodel/treemodel.h

@@ -64,7 +64,7 @@ class TreeModel : public QAbstractItemModel
 
 public:
     TreeModel(const QStringList &headers, const QString &data,
-              QObject *parent = 0);
+              QObject *parent = nullptr);
     ~TreeModel();
 //! [0] //! [1]