settingstree.cpp Example File

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  #include <QtWidgets>

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

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

      QStringList labels;
      labels << tr("Setting") << tr("Type") << tr("Value");
      setHeaderLabels(labels);
      header()->setSectionResizeMode(0, QHeaderView::ResizeToContents);
      header()->setSectionResizeMode(1, QHeaderView::ResizeToContents);
      header()->setSectionResizeMode(2, QHeaderView::Stretch);

      refreshTimer.setInterval(2000);

      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, &QTimer::timeout, this, &SettingsTree::maybeRefresh);
  }

  SettingsTree::~SettingsTree()
  {
  }

  void SettingsTree::setSettingsObject(const SettingsPtr &newSettings)
  {
      settings = newSettings;
      clear();

      if (settings.isNull()) {
          refreshTimer.stop();
      } else {
          refresh();
          if (autoRefresh)
              refreshTimer.start();
      }
  }

  QSize SettingsTree::sizeHint() const
  {
      const QRect availableGeometry = QApplication::desktop()->availableGeometry(this);
      return QSize(availableGeometry.width() * 2 / 3, availableGeometry.height() * 2 / 3);
  }

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

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

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

  void SettingsTree::refresh()
  {
      if (settings.isNull())
          return;

      disconnect(this, &QTreeWidget::itemChanged,
                 this, &SettingsTree::updateSetting);

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

      connect(this, &QTreeWidget::itemChanged,
              this, &SettingsTree::updateSetting);
  }

  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) + QLatin1Char('/'));
          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, QString());
              child->setText(2, QString());
              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 (const 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);
  }