settingstree.cpp Example File

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 #include <QtWidgets>

 #include "settingstree.h"
 #include "variantdelegate.h"

 SettingsTree::SettingsTree(QWidget *parent)
     : QTreeWidget(parent)
 {
     setItemDelegate(new VariantDelegate(this));

     QStringList labels;
     labels << tr("Setting") << tr("Type") << tr("Value");
     setHeaderLabels(labels);
     header()->setSectionResizeMode(0, QHeaderView::Stretch);
     header()->setSectionResizeMode(2, QHeaderView::Stretch);

     settings = 0;
     refreshTimer.setInterval(2000);
     autoRefresh = false;

     groupIcon.addPixmap(style()->standardPixmap(QStyle::SP_DirClosedIcon),
                         QIcon::Normal, QIcon::Off);
     groupIcon.addPixmap(style()->standardPixmap(QStyle::SP_DirOpenIcon),
                         QIcon::Normal, QIcon::On);
     keyIcon.addPixmap(style()->standardPixmap(QStyle::SP_FileIcon));

     connect(&refreshTimer, SIGNAL(timeout()), this, SLOT(maybeRefresh()));
 }

 void SettingsTree::setSettingsObject(QSettings *settings)
 {
     delete this->settings;
     this->settings = settings;
     clear();

     if (settings) {
         settings->setParent(this);
         refresh();
         if (autoRefresh)
             refreshTimer.start();
     } else {
         refreshTimer.stop();
     }
 }

 QSize SettingsTree::sizeHint() const
 {
     return QSize(800, 600);
 }

 void SettingsTree::setAutoRefresh(bool autoRefresh)
 {
     this->autoRefresh = autoRefresh;
     if (settings) {
         if (autoRefresh) {
             maybeRefresh();
             refreshTimer.start();
         } else {
             refreshTimer.stop();
         }
     }
 }

 void SettingsTree::setFallbacksEnabled(bool enabled)
 {
     if (settings) {
         settings->setFallbacksEnabled(enabled);
         refresh();
     }
 }

 void SettingsTree::maybeRefresh()
 {
     if (state() != EditingState)
         refresh();
 }

 void SettingsTree::refresh()
 {
     if (!settings)
         return;

     disconnect(this, SIGNAL(itemChanged(QTreeWidgetItem*,int)),
                this, SLOT(updateSetting(QTreeWidgetItem*)));

     settings->sync();
     updateChildItems(0);

     connect(this, SIGNAL(itemChanged(QTreeWidgetItem*,int)),
             this, SLOT(updateSetting(QTreeWidgetItem*)));
 }

 bool SettingsTree::event(QEvent *event)
 {
     if (event->type() == QEvent::WindowActivate) {
         if (isActiveWindow() && autoRefresh)
             maybeRefresh();
     }
     return QTreeWidget::event(event);
 }

 void SettingsTree::updateSetting(QTreeWidgetItem *item)
 {
     QString key = item->text(0);
     QTreeWidgetItem *ancestor = item->parent();
     while (ancestor) {
         key.prepend(ancestor->text(0) + "/");
         ancestor = ancestor->parent();
     }

     settings->setValue(key, item->data(2, Qt::UserRole));
     if (autoRefresh)
         refresh();
 }

 void SettingsTree::updateChildItems(QTreeWidgetItem *parent)
 {
     int dividerIndex = 0;

     foreach (QString group, settings->childGroups()) {
         QTreeWidgetItem *child;
         int childIndex = findChild(parent, group, dividerIndex);
         if (childIndex != -1) {
             child = childAt(parent, childIndex);
             child->setText(1, "");
             child->setText(2, "");
             child->setData(2, Qt::UserRole, QVariant());
             moveItemForward(parent, childIndex, dividerIndex);
         } else {
             child = createItem(group, parent, dividerIndex);
         }
         child->setIcon(0, groupIcon);
         ++dividerIndex;

         settings->beginGroup(group);
         updateChildItems(child);
         settings->endGroup();
     }

     foreach (QString key, settings->childKeys()) {
         QTreeWidgetItem *child;
         int childIndex = findChild(parent, key, 0);

         if (childIndex == -1 || childIndex >= dividerIndex) {
             if (childIndex != -1) {
                 child = childAt(parent, childIndex);
                 for (int i = 0; i < child->childCount(); ++i)
                     delete childAt(child, i);
                 moveItemForward(parent, childIndex, dividerIndex);
             } else {
                 child = createItem(key, parent, dividerIndex);
             }
             child->setIcon(0, keyIcon);
             ++dividerIndex;
         } else {
             child = childAt(parent, childIndex);
         }

         QVariant value = settings->value(key);
         if (value.type() == QVariant::Invalid) {
             child->setText(1, "Invalid");
         } else {
             child->setText(1, value.typeName());
         }
         child->setText(2, VariantDelegate::displayText(value));
         child->setData(2, Qt::UserRole, value);
     }

     while (dividerIndex < childCount(parent))
         delete childAt(parent, dividerIndex);
 }

 QTreeWidgetItem *SettingsTree::createItem(const QString &text,
                                           QTreeWidgetItem *parent, int index)
 {
     QTreeWidgetItem *after = 0;
     if (index != 0)
         after = childAt(parent, index - 1);

     QTreeWidgetItem *item;
     if (parent)
         item = new QTreeWidgetItem(parent, after);
     else
         item = new QTreeWidgetItem(this, after);

     item->setText(0, text);
     item->setFlags(item->flags() | Qt::ItemIsEditable);
     return item;
 }

 QTreeWidgetItem *SettingsTree::childAt(QTreeWidgetItem *parent, int index)
 {
     if (parent)
         return parent->child(index);
     else
         return topLevelItem(index);
 }

 int SettingsTree::childCount(QTreeWidgetItem *parent)
 {
     if (parent)
         return parent->childCount();
     else
         return topLevelItemCount();
 }

 int SettingsTree::findChild(QTreeWidgetItem *parent, const QString &text,
                             int startIndex)
 {
     for (int i = startIndex; i < childCount(parent); ++i) {
         if (childAt(parent, i)->text(0) == text)
             return i;
     }
     return -1;
 }

 void SettingsTree::moveItemForward(QTreeWidgetItem *parent, int oldIndex,
                                    int newIndex)
 {
     for (int i = 0; i < oldIndex - newIndex; ++i)
         delete childAt(parent, newIndex);
 }