How to be notified on focus? - qml

Question

This question has been edited:
I am working with QML.
I have a custom type called polygon, which is a subcalss of QDeclarativeItem.
I want to be notified when a mouse clicked on a polygon(has focus).
I know QDeclarativeItem has a function: focusInEvent.
I override it in Polygon.cpp, here is polygon.cpp
#include "polygon.h"
#include "point.h"
#include <QPainter>
#include <stdio.h>
#include <iostream>
#include <sstream>
#include <QGraphicsSceneDragDropEvent>
#include <QFocusEvent>
#include "DeclarativeDragDropEvent.h"
using namespace std;
using namespace Qt;
Polygon::Polygon(QDeclarativeItem *parent)
: QDeclarativeItem(parent)
{
// need to disable this flag to draw inside a QDeclarativeItem
setFlag(QDeclarativeItem::ItemHasNoContents, false);
setFlags(ItemIsSelectable|ItemIsMovable|ItemIsFocusable);
setAcceptDrops(true);
}
QVariant Polygon::itemChange(GraphicsItemChange change, const QVariant &value)
{
return QGraphicsItem::itemChange(change, value);
}
void Polygon::focusInEvent ( QFocusEvent * event ){
cout<<"focusin"<<endl;
}
QRectF Polygon::boundingRect() const{
QVector<QPointF> vPnt=listToVector(m_vertices);
return QPolygonF(vPnt).boundingRect();
}
QPainterPath Polygon::shape () const
{
QPainterPath path;
QVector<QPointF> vPnt=listToVector(m_vertices);
path.addPolygon(QPolygonF(vPnt));
return path;
}
QString Polygon::name() const
{
return m_name;
}
void Polygon::setName(const QString &name)
{
m_name = name;
}
QColor Polygon::color() const
{
return m_color;
}
void Polygon::setColor(const QColor &color)
{
m_color = color;
}
void Polygon::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
QPen pen(m_color, 2);
painter->setPen(pen);
painter->setRenderHints(QPainter::Antialiasing, true);
QVector<QPointF> vPnt=listToVector(m_vertices);
painter->setBrush(QBrush(m_color,Qt::SolidPattern));
painter-> drawPolygon(QPolygonF(vPnt),Qt::OddEvenFill);
}
QVector<QPointF> Polygon:: listToVector(QList<Point *> lpnt) const{
QVector<QPointF> vPnt;
for(int i=0;i<lpnt.length();i++){
vPnt.append(QPointF(lpnt.at(i)->x(),lpnt.at(i)->y()));
}
return vPnt;
}
QDeclarativeListProperty<Point> Polygon::vertices()
{
return QDeclarativeListProperty<Point>(this, 0, &Polygon::append_vertex);
}
void Polygon::append_vertex(QDeclarativeListProperty<Point> *list, Point *vertex)
{
Polygon *polygon = qobject_cast<Polygon *>(list->object);
if (polygon) {
vertex->setParentItem(polygon);
polygon->m_vertices.append(vertex);
}
}
And here is my qml file:
import MyTypes 1.0
import QtQuick 1.0
import Qt 4.7
Item {
id:container
width: 300; height: 200
Polygon {
id: aPolygon
anchors.centerIn: parent
width: 100; height: 100
name: "A simple polygon"
color: "blue"
vertices:[
Point{x:20.0; y:40.0},
Point{x:40.0; y:40.0},
Point{x:40.0; y:20.0},
Point{x:20.0; y:20.0}
]
}
}
i override shape, boundingRect as you can see to define Polygon object and to succeed to be notified when a click, a focus appeared in ti
But i can not see cout output in focusInEvent function on screen.
Should i add something on main.cpp of project?
What to do to C++ code know that the object has focus?
Some connection?
Thanks for any idea.

Answer 1

I tried and it seems the problem is with the output "cout", try the "qDebug" and see that you have good code.
All you did is correct.