- Qt 5.5
- Qt Widgets
- Settings Editor Example
- settingstree.cpp Example File
- Qt 5.5.1 Reference Documentation

# settingstree.cpp Example File

tools/settingseditor/settingstree.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
    **   * Redistributions in binary form must reproduce the above copyright
    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of The Qt Company Ltd nor the names of its
    **     contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
    **
    **
    ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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    ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
    **
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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);
    }