path: root/src/templates/qquickswipeview.cpp

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#include "qquickswipeview_p.h"

#include <QtLabsTemplates/private/qquickcontainer_p_p.h>

QT_BEGIN_NAMESPACE

/*!
    \qmltype SwipeView
    \inherits Container
    \instantiates QQuickSwipeView
    \inqmlmodule Qt.labs.controls
    \ingroup qtlabscontrols-navigation
    \ingroup qtlabscontrols-containers
    \brief A swipe view control.

    SwipeView provides a swipe-based navigation model.

    \image qtlabscontrols-swipeview-wireframe.png

    SwipeView is populated with a set of pages. One page is visible at a time.
    The user can navigate between the pages by swiping sideways. Notice that
    SwipeView itself is entirely non-visual. It is recommended to combine it
    with PageIndicator, to give the user a visual clue that there are multiple
    pages.

    \snippet qtlabscontrols-swipeview-indicator.qml 1

    As shown above, SwipeView is typically populated with a static set of
    pages that are defined inline as children of the view. It is also possible
    to \l {Container::addItem()}{add}, \l {Container::insertItem()}{insert},
    \l {Container::moveItem()}{move}, and \l {Container::removeItem()}{remove}
    pages dynamically at run time.

    \sa TabBar, PageIndicator, {Customizing SwipeView}, {Navigation Controls}, {Container Controls}
*/

class QQuickSwipeViewPrivate : public QQuickContainerPrivate
{
    Q_DECLARE_PUBLIC(QQuickSwipeView)

public:
    void resizeItem(QQuickItem *item);
    void resizeItems();

    static QQuickSwipeViewPrivate *get(QQuickSwipeView *view);
};

void QQuickSwipeViewPrivate::resizeItems()
{
    Q_Q(QQuickSwipeView);
    const int count = q->count();
    for (int i = 0; i < count; ++i) {
        QQuickItem *item = itemAt(i);
        if (item)
            item->setSize(QSizeF(contentItem->width(), contentItem->height()));
    }
}

QQuickSwipeViewPrivate *QQuickSwipeViewPrivate::get(QQuickSwipeView *view)
{
    return view->d_func();
}

QQuickSwipeView::QQuickSwipeView(QQuickItem *parent) :
    QQuickContainer(*(new QQuickSwipeViewPrivate), parent)
{
    setFlag(ItemIsFocusScope);
    setActiveFocusOnTab(true);
}

QQuickSwipeViewAttached *QQuickSwipeView::qmlAttachedProperties(QObject *object)
{
    QQuickItem *item = qobject_cast<QQuickItem *>(object);
    if (!item) {
        qWarning() << "SwipeView: attached properties must be accessed from within a child item";
        return Q_NULLPTR;
    }

    return new QQuickSwipeViewAttached(item);
}

void QQuickSwipeView::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    Q_D(QQuickSwipeView);
    QQuickContainer::geometryChanged(newGeometry, oldGeometry);
    d->resizeItems();
}

void QQuickSwipeView::itemAdded(int, QQuickItem *item)
{
    Q_D(QQuickSwipeView);
    if (isComponentComplete())
        item->setSize(QSizeF(d->contentItem->width(), d->contentItem->height()));
}

/*!
    \qmlattachedproperty int Qt.labs.controls::SwipeView::index

    This attached property holds the index of each child item in the SwipeView.

    It is attached to each child item of the SwipeView.
*/

/*!
    \qmlattachedproperty bool Qt.labs.controls::SwipeView::isCurrentItem

    This attached property is \c true if this child is the current item.

    It is attached to each child item of the SwipeView.
*/

/*!
    \qmlattachedproperty SwipeView Qt.labs.controls::SwipeView::view

    This attached property holds the view that manages this child item.

    It is attached to each child item of the SwipeView.
*/

class QQuickSwipeViewAttachedPrivate : public QObjectPrivate, public QQuickItemChangeListener
{
    Q_DECLARE_PUBLIC(QQuickSwipeViewAttached)
public:
    QQuickSwipeViewAttachedPrivate(QQuickItem *item) :
        item(item),
        swipeView(Q_NULLPTR),
        index(-1),
        isCurrent(false)
    {
    }

    ~QQuickSwipeViewAttachedPrivate() {
    }

    void updateView(QQuickItem *parent);

    void itemChildAdded(QQuickItem *, QQuickItem *) Q_DECL_OVERRIDE;
    void itemChildRemoved(QQuickItem *, QQuickItem *) Q_DECL_OVERRIDE;
    void itemParentChanged(QQuickItem *, QQuickItem *) Q_DECL_OVERRIDE;

    void updateIndex();
    void updateIsCurrent();

    void setView(QQuickSwipeView *view);
    void setIndex(int i);
    void setIsCurrent(bool current);

    QQuickItem *item;
    QQuickSwipeView *swipeView;
    int index;
    // Better to store this so that we don't need to lump its calculation
    // together with index's calculation, as it would otherwise need to know
    // the old index to know if it should emit the change signal.
    bool isCurrent;
};

void QQuickSwipeViewAttachedPrivate::updateIndex()
{
    setIndex(swipeView ? QQuickSwipeViewPrivate::get(swipeView)->contentModel->indexOf(item, Q_NULLPTR) : -1);
}

void QQuickSwipeViewAttachedPrivate::updateIsCurrent()
{
    setIsCurrent(swipeView ? swipeView->currentIndex() == index : false);
}

void QQuickSwipeViewAttachedPrivate::setView(QQuickSwipeView *view)
{
    if (view == swipeView)
        return;

    if (swipeView) {
        QQuickItemPrivate *p = QQuickItemPrivate::get(swipeView);
        p->removeItemChangeListener(this, QQuickItemPrivate::Children);

        disconnect(swipeView, &QQuickSwipeView::currentIndexChanged,
            this, &QQuickSwipeViewAttachedPrivate::updateIsCurrent);
        disconnect(swipeView, &QQuickSwipeView::contentChildrenChanged,
            this, &QQuickSwipeViewAttachedPrivate::updateIndex);
    }

    swipeView = view;

    if (swipeView) {
        QQuickItemPrivate *p = QQuickItemPrivate::get(swipeView);
        p->addItemChangeListener(this, QQuickItemPrivate::Children);

        connect(swipeView, &QQuickSwipeView::currentIndexChanged,
            this, &QQuickSwipeViewAttachedPrivate::updateIsCurrent);
        connect(swipeView, &QQuickSwipeView::contentChildrenChanged,
            this, &QQuickSwipeViewAttachedPrivate::updateIndex);
    }

    Q_Q(QQuickSwipeViewAttached);
    emit q->viewChanged();

    updateIndex();
    updateIsCurrent();
}

void QQuickSwipeViewAttachedPrivate::setIsCurrent(bool current)
{
    if (current != isCurrent) {
        isCurrent = current;
        Q_Q(QQuickSwipeViewAttached);
        emit q->isCurrentItemChanged();
    }
}

void QQuickSwipeViewAttachedPrivate::setIndex(int i)
{
    if (i != index) {
        index = i;
        Q_Q(QQuickSwipeViewAttached);
        emit q->indexChanged();
    }
}

void QQuickSwipeViewAttachedPrivate::updateView(QQuickItem *parent)
{
    // parent can be, e.g.:
    // - The contentItem of a ListView (typically the case)
    // - A non-visual or weird type like TestCase, when child items are created from components
    //   wherein the attached properties are used
    // - null, when the item was removed with removeItem()
    QQuickSwipeView *view = Q_NULLPTR;
    if (parent) {
        view = qobject_cast<QQuickSwipeView*>(parent);
        if (!view) {
            if (parent->parentItem() && parent->parentItem()->property("contentItem").isValid()) {
                // The parent is the contentItem of some kind of view.
                view = qobject_cast<QQuickSwipeView*>(parent->parentItem()->parentItem());
            }
        }
    }

    setView(view);
}

void QQuickSwipeViewAttachedPrivate::itemChildAdded(QQuickItem *, QQuickItem *)
{
    updateIndex();
}

void QQuickSwipeViewAttachedPrivate::itemChildRemoved(QQuickItem *, QQuickItem *)
{
    updateIndex();
}

void QQuickSwipeViewAttachedPrivate::itemParentChanged(QQuickItem *, QQuickItem *parent)
{
    updateView(parent);
}

QQuickSwipeViewAttached::QQuickSwipeViewAttached(QQuickItem *item) :
    QObject(*(new QQuickSwipeViewAttachedPrivate(item)), item)
{
    Q_D(QQuickSwipeViewAttached);
    if (item->parentItem()) {
        d->updateView(item->parentItem());
    } else {
        QQuickItemPrivate *p = QQuickItemPrivate::get(item);
        p->addItemChangeListener(d, QQuickItemPrivate::Parent);
    }
}

QQuickSwipeViewAttached::~QQuickSwipeViewAttached()
{
}

QQuickSwipeView *QQuickSwipeViewAttached::view() const
{
    Q_D(const QQuickSwipeViewAttached);
    return d->swipeView;
}

int QQuickSwipeViewAttached::index() const
{
    Q_D(const QQuickSwipeViewAttached);
    return d->index;
}

bool QQuickSwipeViewAttached::isCurrentItem() const
{
    Q_D(const QQuickSwipeViewAttached);
    return d->swipeView ? d->swipeView->currentIndex() == d->index : false;
}

QT_END_NAMESPACE