Not able to call a method of QWidget class from QMainWindow class

[Ahti]

I am trying to call a method of QWidget class from a QMainWindow Class but i keep getting the following error:

Error: no matching function for call to others::constructMessage(...);

My codes:

others.h

#ifndef OTHERS_H
#define OTHERS_H

#include <QWidget>
#include <QMessageBox>
#include <QString>

class others
{
public:
    explicit others(QWidget *parent = 0);
private:
    void setupMessage();
    QMessageBox* constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,QString style) ;
    QMessageBox *errorMessage ;
};

#endif // OTHERS_H

Others.cpp ( as QWidget ) :

#include "others.h"

others::others(QWidget *parent)
{
   setupMessage();
}

QMessageBox* others::constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,
                                  QString style){
    message = new QMessageBox(parent) ;
    message->setGeometry(x,y,w,h);
    message->setStyleSheet(style);
    return message ;
}

void others::setupMessage(){
    errorMessage = constructMessage(this,errorMessage,400,400,0,0
                                    ,"color:#D3D3D3;background-color:rgb(32,52,60);"
                                     "font: 75 bold 12pt Arial;") ;
}

eyecare.cpp ( as QMainWindow ) :

#include "eyecare.h"
#include "others.h"
#include "ui_eyecare.h"
#include "QDesktopWidget"

EyeCare::EyeCare(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::EyeCare)
{    
    ui->setupUi(this);
    QDesktopWidget* widget = qApp->desktop();
    setupSimpleAndErrorMessage() ;
    QRect screenSize = widget->availableGeometry(widget->primaryScreen());
    if ( 0 ){//screenSize.width() > 700 && screenSize.height() > 500)
        setFixedSize(660,460);
    }else{
        errorMessage->setText("Current monitor resolution not supported!");
        errorMessage->show();
    }
 ...

[mostefa]

Hi @Ahti

What is the content of Others.h ?

[Ahti]

@mostefa
others.h

#ifndef OTHERS_H
#define OTHERS_H

#include <QWidget>
#include <QMessageBox>
#include <QString>

class others
{
public:
    explicit others(QWidget *parent = 0);
private:
    void setupMessage();
    QMessageBox* constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,QString style) ;
    QMessageBox *errorMessage ;
};

#endif // OTHERS_H

[mostefa]

Hi again @Ahti

The problem

error: no matching function for call to ‘others::constructMessage(QWidget* const,...)

Is that you have a function which need a QWidget* as first param,

But you in your setup Message() function, you are using this, as first param,(which refer to others.cpp , and others is not a QWidget class) ==> this is the problem.

What you can do is depending on your need:

1. Send parent of other to setupMessage() function , then your function will become setupMessage(QWidget* parent);

Here is my sample

Others.h

#ifndef OTHERS_H
#define OTHERS_H

#include <QWidget>


QT_FORWARD_DECLARE_CLASS(QMessageBox)
QT_FORWARD_DECLARE_CLASS(QString)


class others
{
public:
    explicit others(QWidget *parent = 0);
private:
    /**
     * @brief setupMessage
     * @param parent
     */
    void setupMessage(QWidget *parent);
    /**
     * @brief constructMessage
     * @param parent
     * @param message
     * @param x
     * @param y
     * @param w
     * @param h
     * @param style
     * @return
     */
    QMessageBox* constructMessage(QWidget *parent, QMessageBox *message,
                                  int x, int y, int w, int h, QString style) ;
    /**
     * @brief errorMessage
     */
    QMessageBox *errorMessage ;
};

#endif // OTHERS_H

Others.cpp

#include "others.h"
#include <QMessageBox>

/**
 * @brief others::others
 * @param parent
 */
others::others(QWidget *parent)
{
   setupMessage(parent);
}

/**
 * @brief others::constructMessage
 * @param parent
 * @param message
 * @param x
 * @param y
 * @param w
 * @param h
 * @param style
 * @return
 */
QMessageBox* others::constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,
                                  QString style){
    message = new QMessageBox(parent) ;
    message->setGeometry(x,y,w,h);
    message->setStyleSheet(style);
    return message ;
}


/**
 * @brief others::setupMessage
 * @param parent
 */
void others::setupMessage(QWidget* parent){
    errorMessage = constructMessage(parent,errorMessage,400,400,0,0
                                    ,"color:#D3D3D3;background-color:rgb(32,52,60);"
                                     "font: 75 bold 12pt Arial;") ;
}

2. Or Other class have to inherit from QWidget

Hope this can help,

Best Regards !

[Ahti]

@mostefa

now i get this error: "The program has unexpectedly finished."

My codes:

others.h

#ifndef OTHERS_H
#define OTHERS_H

#include <QWidget>
#include <QMessageBox>
#include <QString>

class others
{
public:
    explicit others(QWidget *parent = 0);
private:
    void setupMessage(QWidget *parent);
    QMessageBox* constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,QString style) ;
    QMessageBox *errorMessage ;
};

#endif // OTHERS_H

others.cpp

#include "others.h"

others::others(QWidget *parent)
{
   setupMessage(parent);
}

QMessageBox* others::constructMessage(QWidget *parent,QMessageBox *message,
                                  int x,int y,int w,int h,
                                  QString style){
    message = new QMessageBox(parent) ;
    message->setGeometry(x,y,w,h);
    message->setStyleSheet(style);
    return message ;
}

void others::setupMessage(QWidget *parent){
    errorMessage = constructMessage(parent,errorMessage,400,400,0,0
                                    ,"color:#D3D3D3;background-color:rgb(32,52,60);"
                                     "font: 75 bold 12pt Arial;") ;
}

[mostefa]

@Ahti said in Not able to call a method of QWidget class from QMainWindow class:

@mostefa

now i get this error: "The program has unexpectedly finished."

The source of this error is not others class , i don't know what you are doing in the other part of your code, you can run the program again with debugger by using F5 , and see what line is causing the problem,

If you want you can share other aprt of your code...

[Ahti]

@mostefa well i have already shared it with u check the "eyecare.cpp" class that i posted in the question

and here is the "main.cpp"

#include "eyecare.h"
#include "others.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication::setStyle(QStyleFactory::create("Fusion")) ;
    QApplication app(argc, argv);

    others win1;
    EyeCare win2;
    win2.setWindowFlags(Qt::FramelessWindowHint|Qt::WindowMinMaxButtonsHint) ;
    win2.showNormal();
    return app.exec();
}

and when i debug my program i get the message saying something like this "The program has terminated because it got a message from the operating system"

[mostefa]

@Ahti said in Not able to call a method of QWidget class from QMainWindow class:

@mostefa well i have already shared it with u check the "eyecare.cpp" class that i posted in the question

and here is the "main.cpp"

#include "eyecare.h"
#include "others.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication::setStyle(QStyleFactory::create("Fusion")) ;
    QApplication app(argc, argv);

    others win1;
    EyeCare win2;
    win2.setWindowFlags(Qt::FramelessWindowHint|Qt::WindowMinMaxButtonsHint) ;
    win2.showNormal();
    return app.exec();
}

and when i debug my program i get the message saying something like this "The program has terminated because it got a message from the operating system"

In eyecare.cpp

you have this line

errorMessage->setText("Current monitor resolution not supported!");

But looks like errorMessage is pointer that is never initialized before ?

[Ahti]

@mostefa
that is initialized in the others.cpp itself in the setupMessage() function.

...
void others::setupMessage(QWidget *parent){
    errorMessage = constructMessage(parent,errorMessage,400,400,0,0
                                    ,"color:#D3D3D3;background-color:rgb(32,52,60);"
                                     "font: 75 bold 12pt Arial;") ;
}

[Ahti]

@mostefa and in main.cpp i am first creating an object of "others" class ( before eyecare class ) which would call the constructor of others class and which in turn would initialize the errorMessage pointer in the setupMessage() function itself.

[mostefa]

What is the content of eyecare.h ....,

and the content of this function setupSimpleAndErrorMessage

You need to provide a more consistent details about what are you doing

[Ahti]

@mostefa The debugger shows the problem is with errorMessage itself.

I am just trying to display a message when i encounter the resolution is less than 700 * 500.

[mostefa]

@Ahti said in Not able to call a method of QWidget class from QMainWindow class:

@mostefa The debugger shows the problem is with errorMessage itself.

For me it's normal , cause as i told you before ,if i refer to the part of code that you shared with us i am not seeing where errorMessage is initialized.

Do you have var memeber called errorMessage on your eyecare.h ?

If yes , and if it's a pointer you need to initialize it,

If you are doing something else , can you PLEASE share the full code of your eyecare.h ?

[Ahti]

@mostefa

well eyecare.h has a lot of content and errorMessage is not initialized in eyecare its initialized in others itself and no there is no such variable as errorMessage in eyecare.h its in others.h