Custom class not declared in scope

Qt Newbie here experiencing a problem where it claims that I did not declare a class which I'm pretty sure is declared.

I cannot for the life of me figure this out. Please help.

Commenting out the problematic lines in Connection.h and .cpp results in compilable output.

Here is a slimmed down version of my code where the problem still exists:

Btw, Map.ui only has a Graphics View dragged into it.

Error message:

Code:

In file included from ../Map/Map.h:17:0,
                 from ../Map/City.cpp:1:
../Map/Connection.h:14:11: error: 'City' was not declared in this scope
     QPair<City*, City*> cities;
           ^
../Map/Connection.h:14:18: error: 'City' was not declared in this scope
     QPair<City*, City*> cities;
                  ^
../Map/Connection.h:14:23: error: template argument 1 is invalid
     QPair<City*, City*> cities;
                       ^
../Map/Connection.h:14:23: error: template argument 2 is invalid
../Map/Connection.h:19:22: error: 'City' was not declared in this scope
     Connection(QPair<City*, City*> cities, int cost);
                      ^
../Map/Connection.h:19:29: error: 'City' was not declared in this scope
     Connection(QPair<City*, City*> cities, int cost);
                             ^
../Map/Connection.h:19:34: error: template argument 1 is invalid
     Connection(QPair<City*, City*> cities, int cost);

Map.pro:

Code:

QT       += core gui
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
TARGET = Map
TEMPLATE = app
 
SOURCES +=\
    City.cpp \
    Connection.cpp \
    Map.cpp \
    Driver.cpp
 
HEADERS  += \
    City.h \
    Connection.h \
    Map.h
 
FORMS    += \
    Map.ui

Map.h:

Code:

#ifndef MAP_H
#define MAP_H
 
#include <QApplication>
#include <QGraphicsItem>
#include <QMainWindow>
#include <QtCore>
#include <QtGui>
#include <QGraphicsScene>
#include <QGraphicsEllipseItem>
#include <QDebug>
#include <QPainter>
#include <QString>
#include <QVector>
 
#include "ui_Map.h"
#include "Connection.h"
#include "City.h"
 
namespace Ui
{
    class Map;
}
 
class Map : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit Map(QWidget *parent = 0);
    ~Map();
 
private:
    Ui::Map *ui;
    QGraphicsScene *scene;
};
 
#endif // MAP_H

Map.cpp:

Code:

#include "Map.h"
#include "ui_Map.h"
 
Map::Map(QWidget *parent) : QMainWindow(parent), ui(new Ui::Map)
{
    ui->setupUi(this);
 
    scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene);
 
    City *c1 = new City(30, 30, 30, "K");
    City *c2 = new City(30, 90, 30, "O");
 
    Connection *conn1 = new Connection(45, 45, 45, 105, 1);
 
    c1->setZValue(4);
    c2->setZValue(4);
    conn1->setZValue(2);
 
    scene->addItem(c1);
    scene->addItem(c2);
    scene->addItem(conn1);
}
 
Map::~Map()
{
    delete ui;
}

City.h:

Code:

#ifndef CITY_H
#define CITY_H
 
#include "Map.h"
 
class City : public QGraphicsItem
{
private:
    int x;
    int y;
    int r;
    QString name;
    QRectF bounds;
    QVector<QPair<City*, int> > neighbors;
 
public:
    City();
    City(int x, int y, int r, QString name);
    int getX() { return this->x; }
    int getY() { return this->y; }
    int getR() { return this->r; }
    QString getName() { return this->name; }
    QVector<QPair<City*, int> > getNeighbors() { return this->neighbors; }
    void setNeighbors(QVector<QPair<City*, int> >) { this->neighbors = neighbors; }
    QRectF boundingRect() const;
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
 
};
 
#endif // CITY_H

City.cpp:

Code:

#include "Map.h"
 
City::City()
{
    this->bounds = QRectF(0, 0, 0, 0);
}
 
City::City(int x, int y, int r, QString name)
{
    this->x = x;
    this->y = y;
    this->r = r;
    this->name = name;
    this->bounds = QRectF(x, y, r, r);
}
 
QRectF City::boundingRect() const
{
    return QRectF(x, y, r, r);
}
 
void City::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rec;
 
    if (this->bounds == QRectF(0, 0, 0, 0))
        rec = boundingRect();
    else
        rec = this->bounds;
 
    QBrush brush(Qt::blue);
    QPen pen(Qt::blue);
 
    painter->setBrush(brush);
    painter->setPen(pen);
    painter->drawEllipse(rec);
}

Connection.h:

Code:

#ifndef CONNECTION_H
#define CONNECTION_H
 
#include "Map.h"
 
class Connection : public QGraphicsItem
{
 
private:
    int x1, x2;
    int y1, y2;
    int cost;
    QRectF bounds;
    QPair<City*, City*> cities;         // PROBLEMATIC LINE -- CLAIMS CITY WAS NOT DECLARED
 
public:
    Connection();
    Connection(int x1, int y1, int x2, int y2, int cost);
    Connection(QPair<City*, City*> cities, int cost);         // PROBLEMATIC LINE -- CLAIMS CITY WAS NOT DECLARED
    int getCost() { return this->cost; }
    QRectF boundingRect() const;
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
};
 
 
#endif // CONNECTION_H

Connection.cpp:

Code:

#include "Map.h"
 
Connection::Connection()
{
    this->bounds = QRectF(0, 0, 0, 0);
}
 
Connection::Connection(int x1, int y1, int x2, int y2, int cost)
{
    this->x1 = x1;
    this->x2 = x2;
    this->y1 = y1;
    this->y2 = y2;
 
    this->bounds = QRectF(x1, x2, y1, y2);
 
}
 
Connection::Connection(QPair<City*, City*> cities, int cost)    // PROBLEMATIC BLOCK
{
    int r = cities.first->getR();
    this->x1 = cities.first->getX() + r/2;
    this->x2 = cities.second->getX() + r/2;
    this->y1 = cities.first->getY() + r/2;
    this->y2 = cities.second->getY() + r/2;
 
    this->cost = cost;
 
    this->bounds = QRectF(x1, x2, y1, y2);
}
 
QRectF Connection::boundingRect() const
{
    return QRectF(0, 0, 0, 0);
}
 
void Connection::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rec;
 
    if (this->bounds == QRectF(0, 0, 0, 0))
        rec = boundingRect();
    else
        rec = this->bounds;
 
    QBrush brush(Qt::red);
    QPen pen(Qt::red);
 
    painter->setPen(pen);
    painter->drawLine(QLine(this->x1, this->y1, this->x2, this->y2));
}

Driver.cpp:

Code:

#include "Map.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Map w;
    w.show();
 
    return a.exec();
}

Thank you for taking the time to look at this. I appreciate any feedback whatsoever. The problematic lines were compilable for a while but it seems that adding certain things "broke" it.

The answer to this thread got me thinking it might be something silly, but my attempts to change the order of things have not fixed it.