SwipeView: add index, view and isCurrentItem attached properties

Task-number: QTBUG-48052
Change-Id: I0d6d27cc352d999d8071b979349f2364f0edf74d
Reviewed-by: J-P Nurmi <jpnurmi@theqtcompany.com>

5 files changed, 302 insertions, 4 deletions

diff --git a/src/controls/qquickcontainer.cpp b/src/controls/qquickcontainer.cpp
index 20b900a2..76a4e192 100644
--- a/src/controls/qquickcontainer.cpp
+++ b/src/controls/qquickcontainer.cpp
@@ -95,6 +95,7 @@ void QQuickContainerPrivate::moveItem(int from, int to)
 void QQuickContainerPrivate::removeItem(int index, QQuickItem *item)
 {
     QQuickItemPrivate::get(item)->removeItemChangeListener(this, QQuickItemPrivate::Destroyed | QQuickItemPrivate::Parent);
+    item->setParentItem(Q_NULLPTR);
     contentData.removeOne(item);
     contentModel->remove(index);
 }
diff --git a/src/imports/extras/qquickswipeview.cpp b/src/imports/extras/qquickswipeview.cpp
index c359a983..ec76d7f2 100644
--- a/src/imports/extras/qquickswipeview.cpp
+++ b/src/imports/extras/qquickswipeview.cpp
@@ -66,6 +66,8 @@ public:
     void moveItem(int from, int to) Q_DECL_OVERRIDE;
     void removeItem(int index, QQuickItem *item) Q_DECL_OVERRIDE;
 
+    static QQuickSwipeViewPrivate *get(QQuickSwipeView *view);
+
     int currentIndex;
     bool updatingCurrent;
 };
@@ -132,6 +134,11 @@ void QQuickSwipeViewPrivate::removeItem(int index, QQuickItem *item)
         emit q->currentIndexChanged();
 }
 
+QQuickSwipeViewPrivate *QQuickSwipeViewPrivate::get(QQuickSwipeView *view)
+{
+    return view->d_func();
+}
+
 QQuickSwipeView::QQuickSwipeView(QQuickItem *parent) :
     QQuickContainer(*(new QQuickSwipeViewPrivate), parent)
 {
@@ -171,6 +178,17 @@ QQuickItem *QQuickSwipeView::currentItem() const
     return itemAt(d->currentIndex);
 }
 
+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);
@@ -187,6 +205,199 @@ void QQuickSwipeView::contentItemChange(QQuickItem *newItem, QQuickItem *oldItem
         connect(newItem, SIGNAL(currentIndexChanged()), this, SLOT(_q_updateCurrent()));
 }
 
+/*!
+    \qmlattachedproperty int QtQuickExtras2::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 QtQuickExtras2::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 QtQuickExtras2::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
 
 #include "moc_qquickswipeview_p.cpp"
diff --git a/src/imports/extras/qquickswipeview_p.h b/src/imports/extras/qquickswipeview_p.h
index 718eccea..68f08783 100644
--- a/src/imports/extras/qquickswipeview_p.h
+++ b/src/imports/extras/qquickswipeview_p.h
@@ -52,6 +52,7 @@
 
 QT_BEGIN_NAMESPACE
 
+class QQuickSwipeViewAttached;
 class QQuickSwipeViewPrivate;
 
 class QQuickSwipeView : public QQuickContainer
@@ -66,6 +67,8 @@ public:
     int currentIndex() const;
     QQuickItem *currentItem() const;
 
+    static QQuickSwipeViewAttached *qmlAttachedProperties(QObject *object);
+
 public Q_SLOTS:
     void setCurrentIndex(int index);
 
@@ -84,8 +87,37 @@ private:
     Q_PRIVATE_SLOT(d_func(), void _q_updateCurrent())
 };
 
+class QQuickSwipeViewAttachedPrivate;
+
+class QQuickSwipeViewAttached : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(int index READ index NOTIFY indexChanged FINAL)
+    Q_PROPERTY(bool isCurrentItem READ isCurrentItem NOTIFY isCurrentItemChanged FINAL)
+    Q_PROPERTY(QQuickSwipeView *view READ view NOTIFY viewChanged FINAL)
+
+public:
+    explicit QQuickSwipeViewAttached(QQuickItem *delegateItem);
+    ~QQuickSwipeViewAttached();
+
+    int index() const;
+    bool isCurrentItem() const;
+    QQuickSwipeView *view() const;
+
+Q_SIGNALS:
+    void indexChanged();
+    void isCurrentItemChanged();
+    void viewChanged();
+
+private:
+    Q_DISABLE_COPY(QQuickSwipeViewAttached)
+    Q_DECLARE_PRIVATE(QQuickSwipeViewAttached)
+};
+
 Q_DECLARE_TYPEINFO(QQuickSwipeView, Q_COMPLEX_TYPE);
 
 QT_END_NAMESPACE
 
+QML_DECLARE_TYPEINFO(QQuickSwipeView, QML_HAS_ATTACHED_PROPERTIES)
+
 #endif // QQUICKSWIPEVIEW_P_H
diff --git a/src/imports/extras/qtquickextras2plugin.cpp b/src/imports/extras/qtquickextras2plugin.cpp
index f1307558..e0208e7a 100644
--- a/src/imports/extras/qtquickextras2plugin.cpp
+++ b/src/imports/extras/qtquickextras2plugin.cpp
@@ -58,6 +58,7 @@ void QtQuickExtras2Plugin::registerTypes(const char *uri)
     qmlRegisterType<QQuickDial>(uri, 2, 0, "AbstractDial");
     qmlRegisterType<QQuickDrawer>(uri, 2, 0, "AbstractDrawer");
     qmlRegisterType<QQuickSwipeView>(uri, 2, 0, "AbstractSwipeView");
+    qmlRegisterType<QQuickSwipeViewAttached>();
     qmlRegisterType<QQuickTumbler>(uri, 2, 0, "AbstractTumbler");
     qmlRegisterType<QQuickTumblerAttached>();
 
diff --git a/tests/auto/extras/data/tst_swipeview.qml b/tests/auto/extras/data/tst_swipeview.qml
index f2694bcf..81c61f45 100644
--- a/tests/auto/extras/data/tst_swipeview.qml
+++ b/tests/auto/extras/data/tst_swipeview.qml
@@ -400,6 +400,16 @@ TestCase {
         ]
     }
 
+    Component {
+        id: pageAttached
+
+        Text {
+            property int index: AbstractSwipeView.index
+            property SwipeView view: AbstractSwipeView.view
+            property bool isCurrentItem: AbstractSwipeView.isCurrentItem
+        }
+    }
+
     function test_move(data) {
         var control = swipeView.createObject(testCase)
 
@@ -407,14 +417,23 @@ TestCase {
         var titles = ["1", "2", "3"]
 
         var i = 0;
-        for (i = 0; i < titles.length; ++i)
-            control.addItem(page.createObject(control, {text: titles[i]}))
+        for (i = 0; i < titles.length; ++i) {
+            var item = pageAttached.createObject(control, {text: titles[i]})
+            control.addItem(item)
+        }
 
         compare(control.count, titles.length)
-        for (i = 0; i < control.count; ++i)
+        for (i = 0; i < control.count; ++i) {
             compare(control.itemAt(i).text, titles[i])
+            compare(control.itemAt(i).AbstractSwipeView.index, i)
+            compare(control.itemAt(i).AbstractSwipeView.isCurrentItem, i === 0)
+        }
 
         control.currentIndex = data.currentBefore
+        for (i = 0; i < control.count; ++i) {
+            compare(control.itemAt(i).AbstractSwipeView.isCurrentItem, i === data.currentBefore)
+        }
+
         control.moveItem(data.from, data.to)
 
         compare(control.count, titles.length)
@@ -425,8 +444,11 @@ TestCase {
         titles.splice(data.to, 0, title)
 
         compare(control.count, titles.length)
-        for (i = 0; i < control.count; ++i)
+        for (i = 0; i < control.count; ++i) {
             compare(control.itemAt(i).text, titles[i])
+            compare(control.itemAt(i).AbstractSwipeView.index, i);
+            compare(control.itemAt(i).AbstractSwipeView.isCurrentItem, i === data.currentAfter)
+        }
 
         control.destroy()
     }
@@ -462,4 +484,35 @@ TestCase {
 
         control.destroy()
     }
+
+    function test_attachedParent() {
+        var control = swipeView.createObject(testCase);
+
+        var page = pageAttached.createObject(testCase);
+        compare(page.view, null);
+        compare(page.index, -1);
+        compare(page.isCurrentItem, false);
+        page.destroy();
+
+        page = pageAttached.createObject(null);
+        compare(page.view, null);
+        compare(page.index, -1);
+        compare(page.isCurrentItem, false);
+
+        control.insertItem(0, page);
+        compare(control.count, 1);
+        compare(page.parent, control.contentItem.contentItem);
+        compare(page.view, control);
+        compare(page.index, 0);
+        compare(page.isCurrentItem, true);
+
+        control.removeItem(0);
+        compare(control.count, 0);
+        compare(page.parent, null);
+        compare(page.view, null);
+        compare(page.index, -1);
+        compare(page.isCurrentItem, false);
+
+        control.destroy();
+    }
 }