linearlayout.cpp Example File

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 #include "linearlayout.h"

 #include <QGraphicsWidget>
 #include <QGraphicsLayoutItem>

 LinearLayoutAttached::LinearLayoutAttached(QObject *parent)
 : QObject(parent), m_stretch(1), m_alignment(Qt::AlignTop), m_spacing(0)
 {
 }

 void LinearLayoutAttached::setStretchFactor(int f)
 {
     if (m_stretch != f) {
         m_stretch = f;
         emit stretchChanged(reinterpret_cast<QGraphicsLayoutItem*>(parent()), m_stretch);
     }
 }

 void LinearLayoutAttached::setSpacing(int s)
 {
     if (m_spacing != s) {
         m_spacing = s;
         emit spacingChanged(reinterpret_cast<QGraphicsLayoutItem*>(parent()), m_spacing);
     }
 }

 void LinearLayoutAttached::setAlignment(Qt::Alignment a)
 {
     if (m_alignment != a) {
         m_alignment = a;
         emit alignmentChanged(reinterpret_cast<QGraphicsLayoutItem*>(parent()), m_alignment);
     }
 }

 GraphicsLinearLayoutStretchItemObject::GraphicsLinearLayoutStretchItemObject(QObject *parent)
     : QObject(parent)
 {
 }

 QSizeF GraphicsLinearLayoutStretchItemObject::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
 {
     Q_UNUSED(which);
     Q_UNUSED(constraint);
     return QSizeF();
 }

 GraphicsLinearLayoutObject::GraphicsLinearLayoutObject(QObject *parent)
 : QObject(parent)
 {
 }

 GraphicsLinearLayoutObject::~GraphicsLinearLayoutObject()
 {
 }

 void GraphicsLinearLayoutObject::insertLayoutItem(int index, QGraphicsLayoutItem *item)
 {
     insertItem(index, item);

     if (LinearLayoutAttached *obj = attachedProperties.value(item)) {
         setStretchFactor(item, obj->stretchFactor());
         setAlignment(item, obj->alignment());
         updateSpacing(item, obj->spacing());
         QObject::connect(obj, SIGNAL(stretchChanged(QGraphicsLayoutItem*,int)),
                          this, SLOT(updateStretch(QGraphicsLayoutItem*,int)));
         QObject::connect(obj, SIGNAL(alignmentChanged(QGraphicsLayoutItem*,Qt::Alignment)),
                          this, SLOT(updateAlignment(QGraphicsLayoutItem*,Qt::Alignment)));
         QObject::connect(obj, SIGNAL(spacingChanged(QGraphicsLayoutItem*,int)),
                          this, SLOT(updateSpacing(QGraphicsLayoutItem*,int)));
     }
 }

 void GraphicsLinearLayoutObject::removeAt(int index)
 {
     QGraphicsLayoutItem *item = itemAt(index);
     if (item) {
         LinearLayoutAttached *obj = attachedProperties.value(item);
         obj->disconnect(this);
         attachedProperties.remove(item);
     }
     QGraphicsLinearLayout::removeAt(index);
 }

 void GraphicsLinearLayoutObject::clearChildren()
 {
     // do not delete the removed items; they will be deleted by the QML engine
     while (count() > 0)
         removeAt(count()-1);
 }

 qreal GraphicsLinearLayoutObject::contentsMargin() const
 {
     qreal a, b, c, d;
     getContentsMargins(&a, &b, &c, &d);
     if (a == b && a == c && a == d)
         return a;
     return -1;
 }

 void GraphicsLinearLayoutObject::setContentsMargin(qreal m)
 {
     setContentsMargins(m, m, m, m);
 }

 void GraphicsLinearLayoutObject::updateStretch(QGraphicsLayoutItem *item, int stretch)
 {
     QGraphicsLinearLayout::setStretchFactor(item, stretch);
 }

 void GraphicsLinearLayoutObject::updateSpacing(QGraphicsLayoutItem* item, int spacing)
 {
     for (int i=0; i < count(); i++){
         if (itemAt(i) == item) {
             QGraphicsLinearLayout::setItemSpacing(i, spacing);
             return;
         }
     }
 }

 void GraphicsLinearLayoutObject::updateAlignment(QGraphicsLayoutItem *item, Qt::Alignment alignment)
 {
     QGraphicsLinearLayout::setAlignment(item, alignment);
 }

 QHash<QGraphicsLayoutItem*, LinearLayoutAttached*> GraphicsLinearLayoutObject::attachedProperties;
 LinearLayoutAttached *GraphicsLinearLayoutObject::qmlAttachedProperties(QObject *obj)
 {
     LinearLayoutAttached *rv = new LinearLayoutAttached(obj);
     if (qobject_cast<QGraphicsLayoutItem*>(obj))
         attachedProperties.insert(qobject_cast<QGraphicsLayoutItem*>(obj), rv);
     return rv;
 }