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Diffstat (limited to 'src/imports/layouts/qquickstacklayout.cpp')
| -rw-r--r-- | src/imports/layouts/qquickstacklayout.cpp | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/src/imports/layouts/qquickstacklayout.cpp b/src/imports/layouts/qquickstacklayout.cpp new file mode 100644 index 0000000000..a223dd0374 --- /dev/null +++ b/src/imports/layouts/qquickstacklayout.cpp @@ -0,0 +1,339 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the Qt Quick Layouts module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qquickstacklayout_p.h" +#include <limits> + +/*! + \qmltype StackLayout + \instantiates QQuickStackLayout + \inherits Item + \inqmlmodule QtQuick.Layouts + \ingroup layouts + \brief The StackLayout class provides a stack of items where + only one item is visible at a time. + + The current visible item can be modified by setting the \l currentIndex property. + The index corresponds to the order of the StackLayout's children. + + In contrast to most other layouts, child Items' \l{Layout::fillWidth}{Layout.fillWidth} and \l{Layout::fillHeight}{Layout.fillHeight} properties + default to \c true. As a consequence, child items are by default filled to match the size of the StackLayout as long as their + \l{Layout::maximumWidth}{Layout.maximumWidth} or \l{Layout::maximumHeight}{Layout.maximumHeight} does not prevent it. + + Items are added to the layout by reparenting the item to the layout. Similarly, removal is done by reparenting the item from the layout. + Both of these operations will affect the layout's \l count property. + + The following code will create a StackLayout where only the 'plum' rectangle is visible. + \code + StackLayout { + id: layout + anchors.fill: parent + currentIndex: 1 + Rectangle { + color: 'teal' + implicitWidth: 200 + implicitHeight: 200 + } + Rectangle { + color: 'plum' + implicitWidth: 300 + implicitHeight: 200 + } + } + \endcode + + Items in a StackLayout support these attached properties: + \list + \li \l{Layout::minimumWidth}{Layout.minimumWidth} + \li \l{Layout::minimumHeight}{Layout.minimumHeight} + \li \l{Layout::preferredWidth}{Layout.preferredWidth} + \li \l{Layout::preferredHeight}{Layout.preferredHeight} + \li \l{Layout::maximumWidth}{Layout.maximumWidth} + \li \l{Layout::maximumHeight}{Layout.maximumHeight} + \li \l{Layout::fillWidth}{Layout.fillWidth} + \li \l{Layout::fillHeight}{Layout.fillHeight} + \endlist + + Read more about attached properties \l{QML Object Attributes}{here}. + \sa ColumnLayout + \sa GridLayout + \sa RowLayout + \sa StackView +*/ + +QQuickStackLayout::QQuickStackLayout(QQuickItem *parent) : + QQuickLayout(*new QQuickStackLayoutPrivate, parent) +{ +} + +/*! + \qmlproperty int StackLayout::count + + This property holds the number of items that belong to the layout. + + Only items that are children of the StackLayout will be candidates for layouting. +*/ +int QQuickStackLayout::count() const +{ + Q_D(const QQuickStackLayout); + return d->count; +} + +/*! + \qmlproperty int StackLayout::currentIndex + + This property holds the index of the child item that is currently visible in the StackLayout. + By default it will be \c -1 for an empty layout, otherwise the default is \c 0 (referring to the first item). +*/ +int QQuickStackLayout::currentIndex() const +{ + Q_D(const QQuickStackLayout); + return d->currentIndex; +} + +void QQuickStackLayout::setCurrentIndex(int index) +{ + Q_D(QQuickStackLayout); + if (index != d->currentIndex) { + QQuickItem *prev = itemAt(d->currentIndex); + QQuickItem *next = itemAt(index); + d->currentIndex = index; + d->explicitCurrentIndex = true; + if (prev) + prev->setVisible(false); + if (next) + next->setVisible(true); + + if (isComponentComplete()) { + rearrange(QSizeF(width(), height())); + emit currentIndexChanged(); + } + } +} + +void QQuickStackLayout::componentComplete() +{ + QQuickLayout::componentComplete(); // will call our geometryChange(), (where isComponentComplete() == true) + + updateLayoutItems(); + + QQuickItem *par = parentItem(); + if (qobject_cast<QQuickLayout*>(par)) + return; + + rearrange(QSizeF(width(), height())); +} + +QSizeF QQuickStackLayout::sizeHint(Qt::SizeHint whichSizeHint) const +{ + QSizeF &askingFor = m_cachedSizeHints[whichSizeHint]; + if (!askingFor.isValid()) { + QSizeF &minS = m_cachedSizeHints[Qt::MinimumSize]; + QSizeF &prefS = m_cachedSizeHints[Qt::PreferredSize]; + QSizeF &maxS = m_cachedSizeHints[Qt::MaximumSize]; + + minS = QSizeF(0,0); + prefS = QSizeF(0,0); + maxS = QSizeF(std::numeric_limits<qreal>::infinity(), std::numeric_limits<qreal>::infinity()); + + const int count = itemCount(); + m_cachedItemSizeHints.resize(count); + for (int i = 0; i < count; ++i) { + SizeHints &hints = m_cachedItemSizeHints[i]; + QQuickStackLayout::collectItemSizeHints(itemAt(i), hints.array); + minS = minS.expandedTo(hints.min()); + prefS = prefS.expandedTo(hints.pref()); + //maxS = maxS.boundedTo(hints.max()); // Can be resized to be larger than any of its items. + // This is the same as QStackLayout does it. + // Not sure how descent makes sense here... + } + } + return askingFor; +} + +int QQuickStackLayout::indexOf(QQuickItem *childItem) const +{ + if (childItem) { + int indexOfItem = 0; + const auto items = childItems(); + for (QQuickItem *item : items) { + if (shouldIgnoreItem(item)) + continue; + if (childItem == item) + return indexOfItem; + ++indexOfItem; + } + } + return -1; +} + +QQuickItem *QQuickStackLayout::itemAt(int index) const +{ + const auto items = childItems(); + for (QQuickItem *item : items) { + if (shouldIgnoreItem(item)) + continue; + if (index == 0) + return item; + --index; + } + return 0; +} + +int QQuickStackLayout::itemCount() const +{ + int count = 0; + const auto items = childItems(); + for (QQuickItem *item : items) { + if (shouldIgnoreItem(item)) + continue; + ++count; + } + return count; +} + +void QQuickStackLayout::setAlignment(QQuickItem * /*item*/, Qt::Alignment /*align*/) +{ + // ### Do we have to respect alignment? +} + +void QQuickStackLayout::invalidate(QQuickItem *childItem) +{ + Q_D(QQuickStackLayout); + if (d->m_ignoredItems.contains(childItem)) { + // If an invalid item gets a valid size, it should be included, as it was added to the layout + updateLayoutItems(); + return; + } + + const int indexOfChild = indexOf(childItem); + if (indexOfChild >= 0 && indexOfChild < m_cachedItemSizeHints.count()) { + m_cachedItemSizeHints[indexOfChild].min() = QSizeF(); + m_cachedItemSizeHints[indexOfChild].pref() = QSizeF(); + m_cachedItemSizeHints[indexOfChild].max() = QSizeF(); + } + + for (int i = 0; i < Qt::NSizeHints; ++i) + m_cachedSizeHints[i] = QSizeF(); + QQuickLayout::invalidate(this); + + QQuickLayoutAttached *info = attachedLayoutObject(this); + + const QSizeF min = sizeHint(Qt::MinimumSize); + const QSizeF pref = sizeHint(Qt::PreferredSize); + const QSizeF max = sizeHint(Qt::MaximumSize); + + const bool old = info->setChangesNotificationEnabled(false); + info->setMinimumImplicitSize(min); + info->setMaximumImplicitSize(max); + info->setChangesNotificationEnabled(old); + if (pref.width() == implicitWidth() && pref.height() == implicitHeight()) { + // In case setImplicitSize does not emit implicit{Width|Height}Changed + if (QQuickLayout *parentLayout = qobject_cast<QQuickLayout *>(parentItem())) + parentLayout->invalidate(this); + } else { + setImplicitSize(pref.width(), pref.height()); + } +} + +void QQuickStackLayout::updateLayoutItems() +{ + Q_D(QQuickStackLayout); + d->m_ignoredItems.clear(); + const int count = itemCount(); + int oldIndex = d->currentIndex; + if (!d->explicitCurrentIndex) + d->currentIndex = (count > 0 ? 0 : -1); + + if (d->currentIndex != oldIndex) + emit currentIndexChanged(); + + if (count != d->count) { + d->count = count; + emit countChanged(); + } + for (int i = 0; i < count; ++i) + itemAt(i)->setVisible(d->currentIndex == i); + + invalidate(); +} + +void QQuickStackLayout::rearrange(const QSizeF &newSize) +{ + Q_D(QQuickStackLayout); + if (newSize.isNull() || !newSize.isValid()) + return; + (void)sizeHint(Qt::PreferredSize); // Make sure m_cachedItemSizeHints are valid + + if (d->currentIndex == -1 || d->currentIndex >= m_cachedItemSizeHints.count()) + return; + QQuickStackLayout::SizeHints &hints = m_cachedItemSizeHints[d->currentIndex]; + QQuickItem *item = itemAt(d->currentIndex); + Q_ASSERT(item); + item->setPosition(QPointF(0,0)); // ### respect alignment? + item->setSize(newSize.expandedTo(hints.min()).boundedTo(hints.max())); + QQuickLayout::rearrange(newSize); +} + +void QQuickStackLayout::collectItemSizeHints(QQuickItem *item, QSizeF *sizeHints) +{ + QQuickLayoutAttached *info = 0; + QQuickLayout::effectiveSizeHints_helper(item, sizeHints, &info, true); + if (!info) + return; + if (info->isFillWidthSet() && !info->fillWidth()) { + const qreal pref = sizeHints[Qt::PreferredSize].width(); + sizeHints[Qt::MinimumSize].setWidth(pref); + sizeHints[Qt::MaximumSize].setWidth(pref); + } + + if (info->isFillHeightSet() && !info->fillHeight()) { + const qreal pref = sizeHints[Qt::PreferredSize].height(); + sizeHints[Qt::MinimumSize].setHeight(pref); + sizeHints[Qt::MaximumSize].setHeight(pref); + } +} + +bool QQuickStackLayout::shouldIgnoreItem(QQuickItem *item) const +{ + const bool ignored = QQuickItemPrivate::get(item)->isTransparentForPositioner(); + if (ignored) + d_func()->m_ignoredItems << item; + return ignored; +} |