我在Train Traffic Controller软件项目中工作。 我在这个项目中的职责是开发可视化铁路GUI。
我们正在用Qt实施该项目。
到现在为止,我正在使用QGraphicsLinearLayout来保存我的物品。
我正在使用布局,因为我不想计算每个项目的坐标。
到目前为止,我编写了项类来添加布局。例如,SwitchItem类符号化
现实世界中的铁路开关。每个项目类都负责自己的绘画和活动。
到目前为止一切顺利。
现在我需要一个可以包含两个或更多项的复合项。该类将负责绘制其中包含的项目。我需要这个类,因为我必须在同一个布局单元格中放置两个或更多个项目。如果我不把它们放在同一个单元格中,我就不能使用布局。见下图。
Composite Item http://img169.imageshack.us/img169/9079/composite1.jpg BlockSegmentItem和SignalItem在同一个单元格内。
CompositeItem头文件
#include <QtCore/QList>
#include <QtGui/QGraphicsLayoutItem>
#include <QtGui/QGraphicsItemGroup>
#include <QtGui/QGraphicsSceneMouseEvent>
#include <QtGui/QGraphicsSceneContextMenuEvent>
#include "fielditem.h"
class CompositeItem : public FieldItem
{
Q_OBJECT
public:
CompositeItem(QString id,QList<FieldItem *> _children);
~CompositeItem();
QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF(-1,-1)) const;
QRectF boundingRect() const;
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget /* = 0 */);
void contextMenuEvent(QGraphicsSceneContextMenuEvent *event);
private:
QList<FieldItem *> children;
};
//CompositeItem implementation
#include "compositeitem.h"
CompositeItem::CompositeItem(QString id,QList<FieldItem *> _children)
{
children = _children;
}
CompositeItem::~CompositeItem()
{
}
QRectF CompositeItem::boundingRect() const
{
FieldItem *child;
QRectF rect(0,0,0,0);
foreach(child,children)
{
rect = rect.united(child->boundingRect());
}
return rect;
}
void CompositeItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget )
{
FieldItem *child;
foreach(child,children)
{
child->paint(painter,option,widget);
}
}
QSizeF CompositeItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
QSizeF itsSize(0,0);
FieldItem *child;
foreach(child,children)
{
// if its size empty set first child size to itsSize
if(itsSize.isEmpty())
itsSize = child->sizeHint(Qt::PreferredSize);
else
{
QSizeF childSize = child->sizeHint(Qt::PreferredSize);
if(itsSize.width() < childSize.width())
itsSize.setWidth(childSize.width());
itsSize.setHeight(itsSize.height() + childSize.height());
}
}
return itsSize;
}
void CompositeItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
{
qDebug()<<"Test";
}
//Code that add items to scene
//Subclass of QGraphicsWidget for future extension
FieldItemContainer *widget;
while(!itemGroupNode.isNull())
{
//Subclass of QGraphicsLinearLayout for future extension
FieldItemGroupLayout *layout = new FieldItemGroupLayout;
int layoutX = itemGroupNode.toElement().attribute("X").toInt();
int layoutY = itemGroupNode.toElement().attribute("Y").toInt();
layout->setSpacing(1);
QDomNode itemNode = itemGroupNode.toElement().namedItem("Item");
while (!itemNode.isNull() && itemNode.nodeType() == QDomNode::ElementNode)
{
FieldItem * item;
//Create proper item
item = FieldItemFactory::createFieldItem(itemNode);
//Add item to layout
layout->addItem(item);
itemNode = itemNode.nextSibling();
}
widget = new FieldItemContainer;
//Set layout to widget
widget->setLayout(layout);
widget->setPos(layoutX,layoutY);
//Add widget to scene
itsScene->addItem(widget);
itemGroupNode = itemGroupNode.nextSibling();
}
//FieldItemFactory implementation
FieldItem* FieldItemFactory::createFieldItem(QDomNode itemNode)
{
FieldItem *item;
//Common for all items
QString itemId = itemNode.toElement().attribute("id");
QString itemType = itemNode.toElement().attribute("type");
int x1 = itemNode.namedItem("X1").toElement().text().toInt();
int y1 = itemNode.namedItem("Y1").toElement().text().toInt();
//Only for Block part items
int x2 = 0;
int y2 = 0;
QString signalization = "";
////***********************
//Only for signal items
QString source = "";
int width = 0;
int height = 0;
///********************
//Only for switch items
QString normalPositionSource = "";
QString reversePositionSource = "";
///********************
///Labeling
QDomNode itemLabelNode = itemNode.namedItem("Label");
FieldItemLabel label;
label.x1 = itemLabelNode.namedItem("X1").toElement().text().toInt();
label.y1 = itemLabelNode.namedItem("Y1").toElement().text().toInt();
label.text = itemLabelNode.namedItem("Text").toElement().text().trimmed();
label.rotateAngle = itemLabelNode.namedItem("RotateAngle").toElement().text().toInt();
label.hideScale = itemLabelNode.namedItem("HideScale").toElement().text().toInt();
///*****************
if(itemType == FieldProperty::BLOCKSEGMENTITEM)
{
x2 = itemNode.namedItem("X2").toElement().text().toInt();
y2 = itemNode.namedItem("Y2").toElement().text().toInt();
signalization = itemNode.namedItem("Signalization").toElement().text().trimmed();
item = new BlockSegmentItem(itemId,x1,y1,x2,y2,
label,signalization);
}
else if(itemType == FieldProperty::SWITCHITEM)
{
normalPositionSource = itemNode.namedItem("Normal").toElement().text().trimmed();
reversePositionSource = itemNode.namedItem("Reverse").toElement().text().trimmed();
item = new SwitchItem(itemId,x1,y1,FieldProperty::SWITCH_WIDTH,
FieldProperty::SWITCH_HEIGHT,label,
normalPositionSource,reversePositionSource);
}
else if(itemType == FieldProperty::SIGNALITEM)
{
source = itemNode.namedItem("Source").toElement().text().trimmed();
width = itemNode.namedItem("Width").toElement().text().toInt();
height = itemNode.namedItem("Height").toElement().text().toInt();
item = new SignalItem(itemId,x1,y1,width,height,label,source);
}
else if(itemType == FieldProperty::TRAINIDBOXITEM)
{
item = new TrainIdBox(itemId,x1,y1);
}
else if(itemType == FieldProperty::COMPOSITEITEM)
{
QList<FieldItem *> children;
for (int i = 0; i < itemNode.childNodes().count(); i++)
{
children.push_back(createFieldItem(itemNode.childNodes().at(i)));
}
item = new CompositeItem(itemId,children);
}
return item;
}
//At last part of xml data that I used to create BlockSegmentItem and SignalItem in same cell
<Item id="CI5@MIT" type="COMPOSITE">
<Item id="001BT@MIT" type="BLOCKSEGMENT">
<Label>
<Text>001BT</Text>
<X1>70</X1>
<Y1>10</Y1>
</Label>
<X1>0</X1>
<Y1>15</Y1>
<X2>150</X2>
<Y2>15</Y2>
</Item>
<Item id="B2D@MIT" type="SIGNAL">
<Label>
<Text>B2D</Text>
<X1>15</X1>
<Y1>40</Y1>
</Label>
<X1>0</X1>
<Y1>20</Y1>
<Width>40</Width>
<Height>10</Height>
<Source>Resources/graphics/signals/sgt3lr.svg</Source>
</Item>
</Item>
此代码适用于绘画,但涉及项目事件则存在问题。 QGraphicsScene将复合项视为单个项目,该项目适用于布局,但不适用于事件。因为每个项目都有自己的事件实现。(例如,SignalItem有其特殊的上下文菜单事件。)
我必须单独处理项目事件。我还需要一个布局的复合项实现。我怎样才能克服这种困境?
答案 0 :(得分:0)
您可以使用QGraphicsScene :: sendEvent()将事件传递给子级。这是一个应该解决您的问题的示例。
void CompositeItem::sceneEvent(QEvent * event)
{
if (scene()) {
FieldItem *child;
foreach(child, children) {
scene()->sendEvent(child, event);
}
}
}
在我看来,复合项目可以理解为分层布局,其中一个项目在另一个上面绘制。这样的布局还不存在,但如果它们出现在将来我也不会感到惊讶。