QLabel text

[eXevio]

Hello guys i am pretty new to Qt and you may find my question silly.

I have created 3 simple files
main.cpp
TextController.h
TextController.cpp

What i do , is i have a QLabel in the main Widget and i want to print the contents of the QLabel .
i tried in the TextController.h to get the Qlabel text by--> QString text = myLabel->text() and then cout<<text<<endl; but i get compile error.
I have searched all of over the net but nothing :/

//TextController.h
@#include <qobject.h>
class TextController : public QObject
{
Q_OBJECT
public:
TextController();
private slots:
void Print();
};@

// TextControllet.cpp
@#include "TextController.h"
#include <iostream>
#include <qstring.h>

using namespace std;
TextController::TextController()
{
QString labelText = myLabel->text();
}
void TextController::Print()
{ //print()

cout<<"Label Text Goes Here!"<<endl;
} //print()@

// main
@#include <qapplication.h>
#include <qlabel.h>
#include <qpushbutton.h>
#include "TextController.h"

int main(int argc, char *argv[])
{
QApplication myApp(argc,argv);

QWidget *myWidget = new QWidget;
myWidget->setGeometry(400,300,120,90);

TextController myTextController;

QLabel *myLabel = new QLabel("Hello World!",myWidget,0);
QPushButton *myPrintButton = new QPushButton("Print",myWidget);
QPushButton *myQuitButton = new QPushButton("Exit",myWidget);

myLabel->setGeometry(10,10,100,30);
myPrintButton->setGeometry(10,50,100,30);
myQuitButton->setGeometry(10,90,100,30);

QObject::connect(myPrintButton,SIGNAL(clicked()),&myTextController,SLOT(Print()));
QObject::connect(myQuitButton,SIGNAL(clicked()),&myApp,SLOT(quit()));
myWidget->show();
return myApp.exec();
}@

any help would be appreciated

[dbzhang800]

Hi,

qDebug() can be used in such cases.

Regards,

Debao

[andre]

quote author="eXevio" date="1332294119" but i get compile error. [/quote]

So, what is that error exactly?

[lgeyer]

• Qt headers are usually included using <code>#include <QtModule/QClass></code>, not <code>#include <qclass.h></code>
• You are missing a call to the parent constructor in TextController.cpp #6
• labelText is a local variable in TextController #8
• myLabel is not a member in TextController #8
• Qt widgets are usually positioned using layout managers, not absolute positioning

labelText has to be a member, so it is accessible in TextController::Print().

myLabel is unknown to TextController; it has to be passed to TextController (for example in the constructor or using a setter) and stored in a member variable.

[eXevio]

@TextController.cpp: In constructor ‘TextController::TextController()’:
TextController.cpp:8: error: ‘myLabel’ was not declared in this scope
TextController.cpp:8: warning: unused variable ‘labelText’
TextController.cpp: In member function ‘void TextController::Print()’:
TextController.cpp:13: error: ‘labelText’ was not declared in this scope
make: *** [TextController.o] Error 1
@

and my TextController.cpp looks like:
@#include "TextController.h"
#include <iostream>
#include <qstring.h>

using namespace std;
TextController::TextController()
{
QString labelText = myLabel->text();
}
void TextController::Print()
{ //print()

cout<<labelText<<endl;
} //print()@

[eXevio]

myLabel is unknown to TextController; it has to be passed to TextController (for example in the constructor or using a setter) and stored in a member variable.[/quote]
Thanks For the info Lukas, i could figure out that but the question is how to implement it :o

[lgeyer]

There are various ways - depending on the design of your application. The obvious one is passing the label to TextController in the constructor, using a setter or a combination of both.
@
class TextController
{
public:
TextController(QLabel *label) : label_(label)
{
}

void setLabel(QLabel *label)
{
    label_ = label;
}

QLabel *label() const
{
    return label_;
}

void Print()
{
    if(label_ != 0)
    {
        cout << label->text().toStdString();
    }
}

private:
QLabel *label_;
}

....

TextController myTextController(myLabel);
....
myTextController.setLabel(myLabel);
@