Open second window in Qt - c++

Question

I am trying to compile my code written in C++, using Qt Creator. I am trying to create second window which will appear after click to menu item in main window and this window should have separate .ui file. But during compilation I get this error:
/home/martin/Code/C++/Map_generator/map_generator/preferenceswindow.cpp:4: error: prototype for 'Ui::PreferencesWindow::PreferencesWindow(QWidget*)' does not match any in class 'Ui::PreferencesWindow'
Ui::PreferencesWindow::PreferencesWindow(QWidget *parent)
^
/home/bo/Code/C++/Map_generator/build-map_generator-Desktop-Debug/ui_preferenceswindow.h:88: error: candidates are: constexpr Ui::PreferencesWindow::PreferencesWindow(Ui::PreferencesWindow&&)
class PreferencesWindow: public Ui_PreferencesWindow {};
^
What could be wrong?
preferenceswindow.h
#ifndef PREFERENCESWINDOW_H
#define PREFERENCESWINDOW_H
#include <QWidget>
namespace Ui
{
class PreferencesWindow;
}
class PreferencesWindow : public QWidget
{
Q_OBJECT
public:
explicit PreferencesWindow(QWidget *parent = 0);
signals:
//public Q_SLOTS:
private:
PreferencesWindow *uip;
};
#endif // PREFERENCESWINDOW_H
preferenceswindow.cpp
#include "preferenceswindow.h"
#include "ui_preferenceswindow.h"
Ui::PreferencesWindow::PreferencesWindow(QWidget *parent)
:QWidget(parent), uip(new Ui::PreferencesWindow)
{
uip->setupUi(this);
}
preferenceswindow.ui file
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>PreferencesWindow</class>
<widget class="QWidget" name="PreferencesWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>326</width>
<height>159</height>
</rect>
</property>
<property name="windowTitle">
<string>Form</string>
</property>
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>200</x>
<y>100</y>
<width>99</width>
<height>27</height>
</rect>
</property>
<property name="text">
<string>Save</string>
</property>
</widget>
<widget class="QSpinBox" name="spinBox">
<property name="geometry">
<rect>
<x>90</x>
<y>100</y>
<width>81</width>
<height>27</height>
</rect>
</property>
<property name="minimum">
<number>1</number>
</property>
<property name="maximum">
<number>200</number>
</property>
<property name="value">
<number>15</number>
</property>
</widget>
<widget class="QSpinBox" name="spinBox_2">
<property name="geometry">
<rect>
<x>90</x>
<y>20</y>
<width>81</width>
<height>27</height>
</rect>
</property>
<property name="minimum">
<number>1</number>
</property>
<property name="maximum">
<number>1000</number>
</property>
<property name="value">
<number>100</number>
</property>
</widget>
<widget class="QSpinBox" name="spinBox_3">
<property name="geometry">
<rect>
<x>90</x>
<y>60</y>
<width>81</width>
<height>27</height>
</rect>
</property>
<property name="minimum">
<number>1</number>
</property>
<property name="maximum">
<number>1000</number>
</property>
<property name="value">
<number>60</number>
</property>
</widget>
<widget class="QLabel" name="label">
<property name="geometry">
<rect>
<x>20</x>
<y>30</y>
<width>67</width>
<height>17</height>
</rect>
</property>
<property name="text">
<string>Columns</string>
</property>
</widget>
<widget class="QLabel" name="label_2">
<property name="geometry">
<rect>
<x>20</x>
<y>70</y>
<width>67</width>
<height>17</height>
</rect>
</property>
<property name="text">
<string>Rows</string>
</property>
</widget>
<widget class="QLabel" name="label_3">
<property name="geometry">
<rect>
<x>20</x>
<y>110</y>
<width>67</width>
<height>17</height>
</rect>
</property>
<property name="text">
<string>Grid Size</string>
</property>
</widget>
</widget>
<resources/>
<connections/>
</ui>

Answer 1

Your uip variable is declared as PreferencesWindow, when you want it to be declared as Ui::PreferencesWindow:
private:
PreferencesWindow *uip;
change it to
private:
Ui::PreferencesWindow *uip;
You are also defining a Ui::PreferencesWindow constructor in preferenceswindow.cpp. This is not what you want to do. You want to define PreferencesWindow constructor there. Like this:
PreferencesWindow::PreferencesWindow(QWidget *parent)
:QWidget(parent), uip(new Ui::PreferencesWindow)
{
uip->setupUi(this);
}