QObject::connect: No such signal GLWidget::textChanged

CroCo

I'm moving from GLUT to Qt. I've implemented simple projects with QGLWidget. Now I would like to interact with other widgets in MainWindow. My problem is that how QGLWidget interacts with MainWindow? I'm implemented the following sample but I get this error
QObject::connect: No such signal GLWidget::textChanged(const QString &text) in ..\KeyEvent\mainwindow.cpp:12 QObject::connect: (receiver name: 'textEdit')

main.cpp

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

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

class GLWidget;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_startButton_clicked();

private:
    Ui::MainWindow *ui;
    GLWidget *glwidget;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    glwidget = new GLWidget;

connect(    glwidget, SIGNAL(textChanged(const QString &text)),
        ui->textEdit,   SLOT(    setText(const QString &text))  );

//connect(ui->startButton, SIGNAL(clicked()),
//               glwidget,   SLOT(  print())  );
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_startButton_clicked()
{
}

glwidget.h

#ifndef GLWIDGET_H
#define GLWIDGET_H

#include <QTimer>
#include <QtOpenGL/QGLWidget>
#include <gl/GLU.h>
#include <gl/GL.h>
#include <QKeyEvent>

class GLWidget : public QGLWidget
{
    Q_OBJECT

public:
    explicit GLWidget(QWidget *parent = 0);
    ~GLWidget();

protected:
    void initializeGL();
    void paintGL();
    void resizeGL(int w, int h);

//--------------( Key Event )-----------------//
void keyPressEvent(QKeyEvent *event);
void keyReleaseEvent(QKeyEvent *event);

signals:
void textChanged(const QString &text);

public slots:
    void print();

private:
    QTimer timer;
};

#endif // GLWIDGET_H

glwidget.cpp

#include "glwidget.h"
#include <QDebug>


GLWidget::GLWidget(QWidget *parent)
: QGLWidget(parent)

{

QGLFormat glFormat;
glFormat.setDoubleBuffer(true);
glFormat.setDepth(true);
setFormat(glFormat);


connect(&timer, SIGNAL(timeout()), this, SLOT(updateGL()));
timer.start(10);
}

GLWidget::~GLWidget()
{
}

void GLWidget::initializeGL()
{
    glClearColor(0,0,0,1);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHTING); 
    glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
    glEnable(GL_COLOR_MATERIAL);
}

void GLWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glRotatef(0.5, 0, 1, 0);

    glBegin(GL_TRIANGLES);
        glColor3f(1.0, 0.0, 0.0);
        glVertex3f(-0.5, -0.5, 0);
        glColor3f(0.0, 1.0, 0.0);
        glVertex3f( 0.5, -0.5, 0);
        glColor3f(0.0, 0.0, 1.0);
        glVertex3f( 0.0,  0.5, 0);
    glEnd();
}

void GLWidget::resizeGL(int w, int h)
{
    glViewport(0,0,w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45, (float)w/h, 0.01, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(0,0,5,0,0,0,0,1,0);
}

 void GLWidget::keyPressEvent(QKeyEvent *event)
 {
     qDebug() << event->text() << " is pressed ...";
     emit textChanged(event->text());
     update();
 }

 void GLWidget::keyReleaseEvent(QKeyEvent * event)
 {
     qDebug() << event->text() << " is released ...";
 }

void GLWidget::print()
{
    qDebug() << "print()";
    update();
}

SGaist

Hi,

You connect statement is wrong. It should be:

connect(glwidget, SIGNAL(textChanged(QString)),
        ui->textEdit,   SLOT(setText(QString)));

Never put the variable name in the SIGNAL or SLOT macros