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0

I'm writing a code that i used QWidget to create the widget that i wanted and later i set this widget as a central widget.

So far so good, but in the widget i had buttons, that if one of them was clicked it changed a string variable value.

After that i set this as a central widget, i created the same buttons in the MainWindow, but i can't change the values of the variables that i want anymore :(

 ..... 
 linha_button=new QPushButton(this);
 linha_button->setGeometry(QRect(QPoint(41,924),QSize(40,40)));
 linha_button->setIcon(QIcon(url_linha));
 linha_button->setIconSize(QSize(30,30));
 linha_button->setCheckable(true);
 QObject::connect(linha_button, SIGNAL (clicked()), this, SLOT (lihaButton()));

void MainWindow::lihaButton()

 Diagrama::modo="trafo";

The variable modo is declared in the widget named Diagrama.
This code don't execute, the error is:
invalid use of non=static data member 'modo'

How can I fix this??

c++ qt qt5

share|improve this question

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

add a comment | 

0

I'm writing a code that i used QWidget to create the widget that i wanted and later i set this widget as a central widget.

So far so good, but in the widget i had buttons, that if one of them was clicked it changed a string variable value.

After that i set this as a central widget, i created the same buttons in the MainWindow, but i can't change the values of the variables that i want anymore :(

 ..... 
 linha_button=new QPushButton(this);
 linha_button->setGeometry(QRect(QPoint(41,924),QSize(40,40)));
 linha_button->setIcon(QIcon(url_linha));
 linha_button->setIconSize(QSize(30,30));
 linha_button->setCheckable(true);
 QObject::connect(linha_button, SIGNAL (clicked()), this, SLOT (lihaButton()));

void MainWindow::lihaButton()

 Diagrama::modo="trafo";

The variable modo is declared in the widget named Diagrama.
This code don't execute, the error is:
invalid use of non=static data member 'modo'

How can I fix this??

c++ qt qt5

share|improve this question

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

add a comment | 

I'm writing a code that i used QWidget to create the widget that i wanted and later i set this widget as a central widget.

So far so good, but in the widget i had buttons, that if one of them was clicked it changed a string variable value.

After that i set this as a central widget, i created the same buttons in the MainWindow, but i can't change the values of the variables that i want anymore :(

 ..... 
 linha_button=new QPushButton(this);
 linha_button->setGeometry(QRect(QPoint(41,924),QSize(40,40)));
 linha_button->setIcon(QIcon(url_linha));
 linha_button->setIconSize(QSize(30,30));
 linha_button->setCheckable(true);
 QObject::connect(linha_button, SIGNAL (clicked()), this, SLOT (lihaButton()));

void MainWindow::lihaButton()

 Diagrama::modo="trafo";

The variable modo is declared in the widget named Diagrama.
This code don't execute, the error is:
invalid use of non=static data member 'modo'

How can I fix this??

c++ qt qt5

share|improve this question

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

 ..... 
 linha_button=new QPushButton(this);
 linha_button->setGeometry(QRect(QPoint(41,924),QSize(40,40)));
 linha_button->setIcon(QIcon(url_linha));
 linha_button->setIconSize(QSize(30,30));
 linha_button->setCheckable(true);
 QObject::connect(linha_button, SIGNAL (clicked()), this, SLOT (lihaButton()));

void MainWindow::lihaButton()

 Diagrama::modo="trafo";

share|improve this question

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

share|improve this question

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

edited Mar 27 at 20:21

ΦXocę 웃 Пepeúpa ツ

35.4k1212 gold badges4343 silver badges6868 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

asked Mar 27 at 20:00

Lukas MüllerLukas Müller

1155 bronze badges

2 Answers
2

active

oldest

votes

1

Declare a setter as a slot in your Diagrama class and connect your MainWindow to it:

class Diagrama: public QWidget

Q_OBJECT
...
public slots:
 void changeModo() modo = "trafo"; 
;

In your MainWindow class:

QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo()));

share|improve this answer

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  it says that is not declared in this scope :(
  
  – Lukas Müller
  Mar 27 at 20:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo())); - better; QObject::connect(linha_button, &QPushButton::clicked, yourDiagramaObject, &Diagrama::changeModo); - will be checked at compile time, not run time and will be faster since it does not involve a bunch of nasty string comparisons (which the old-style macros cause). Use the new compile time checked, member function pointer based, syntax, please. The old SIGNAL() and SLOT() macro crap needs to die.
  
  – Jesper Juhl
  Mar 27 at 20:16
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @lukas Müller, you have to change yourDiagramaObject by the name of your own object.
  
  – Romha Korev
  Mar 27 at 20:38
  

  
  
  
  

add a comment | 

0

Or use lambda

connect(linha_button,&QPushButton::clicked,[this]() modo = "trafo"; ) ;

share|improve this answer

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  His modo variable is in another class. It will not fix his problem, unfortunately.
  
  – Romha Korev
  Mar 28 at 8:19
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  if it is static maybe AnotherClass::modo in this case Diagrama::modo connect(linha_button,&QPushButton::clicked,[this]() Diagrama::modo = "trafo"; ) ;
  
  – Artmetic
  Mar 29 at 10:53
  
  

  
  
  
  

add a comment | 

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1

Declare a setter as a slot in your Diagrama class and connect your MainWindow to it:

class Diagrama: public QWidget

Q_OBJECT
...
public slots:
 void changeModo() modo = "trafo"; 
;

In your MainWindow class:

QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo()));

share|improve this answer

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  it says that is not declared in this scope :(
  
  – Lukas Müller
  Mar 27 at 20:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo())); - better; QObject::connect(linha_button, &QPushButton::clicked, yourDiagramaObject, &Diagrama::changeModo); - will be checked at compile time, not run time and will be faster since it does not involve a bunch of nasty string comparisons (which the old-style macros cause). Use the new compile time checked, member function pointer based, syntax, please. The old SIGNAL() and SLOT() macro crap needs to die.
  
  – Jesper Juhl
  Mar 27 at 20:16
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @lukas Müller, you have to change yourDiagramaObject by the name of your own object.
  
  – Romha Korev
  Mar 27 at 20:38
  

  
  
  
  

add a comment | 

1

Declare a setter as a slot in your Diagrama class and connect your MainWindow to it:

class Diagrama: public QWidget

Q_OBJECT
...
public slots:
 void changeModo() modo = "trafo"; 
;

In your MainWindow class:

QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo()));

share|improve this answer

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  it says that is not declared in this scope :(
  
  – Lukas Müller
  Mar 27 at 20:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo())); - better; QObject::connect(linha_button, &QPushButton::clicked, yourDiagramaObject, &Diagrama::changeModo); - will be checked at compile time, not run time and will be faster since it does not involve a bunch of nasty string comparisons (which the old-style macros cause). Use the new compile time checked, member function pointer based, syntax, please. The old SIGNAL() and SLOT() macro crap needs to die.
  
  – Jesper Juhl
  Mar 27 at 20:16
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @lukas Müller, you have to change yourDiagramaObject by the name of your own object.
  
  – Romha Korev
  Mar 27 at 20:38
  

  
  
  
  

add a comment | 

Declare a setter as a slot in your Diagrama class and connect your MainWindow to it:

class Diagrama: public QWidget

Q_OBJECT
...
public slots:
 void changeModo() modo = "trafo"; 
;

In your MainWindow class:

QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo()));

share|improve this answer

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

class Diagrama: public QWidget

Q_OBJECT
...
public slots:
 void changeModo() modo = "trafo"; 
;

QObject::connect(linha_button, SIGNAL (clicked()), yourDiagramaObject, SLOT(changeModo()));

share|improve this answer

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

answered Mar 27 at 20:07

Romha KorevRomha Korev

4,54522 gold badges1616 silver badges2828 bronze badges

0

Or use lambda

connect(linha_button,&QPushButton::clicked,[this]() modo = "trafo"; ) ;

share|improve this answer

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  His modo variable is in another class. It will not fix his problem, unfortunately.
  
  – Romha Korev
  Mar 28 at 8:19
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  if it is static maybe AnotherClass::modo in this case Diagrama::modo connect(linha_button,&QPushButton::clicked,[this]() Diagrama::modo = "trafo"; ) ;
  
  – Artmetic
  Mar 29 at 10:53
  
  

  
  
  
  

add a comment | 

0

Or use lambda

connect(linha_button,&QPushButton::clicked,[this]() modo = "trafo"; ) ;

share|improve this answer

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  His modo variable is in another class. It will not fix his problem, unfortunately.
  
  – Romha Korev
  Mar 28 at 8:19
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  if it is static maybe AnotherClass::modo in this case Diagrama::modo connect(linha_button,&QPushButton::clicked,[this]() Diagrama::modo = "trafo"; ) ;
  
  – Artmetic
  Mar 29 at 10:53
  
  

  
  
  
  

add a comment | 

Or use lambda

connect(linha_button,&QPushButton::clicked,[this]() modo = "trafo"; ) ;

share|improve this answer

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

connect(linha_button,&QPushButton::clicked,[this]() modo = "trafo"; ) ;

share|improve this answer

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

edited Mar 27 at 22:35

eyllanesc

106k1212 gold badges3838 silver badges7171 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges

answered Mar 27 at 22:33

ArtmeticArtmetic

32522 silver badges88 bronze badges