[Solved]Why my defined QAction has no response?

[mybiandou]

Hello, everyone.

I am a beginner of Qt programming.

I just make a simple exercise following example "widgets-imageviewer":http://doc.qt.digia.com/latest/widgets-imageviewer.html

In my program , I made a QAction "rgbFilterAct" under QMenu "processingMenu" , and connected it with function filterRGB(void) to display a RGB range choosing dialogue.

But it has no response after I click the menu item rgbFilterAct.

Can anyone kindly tell me why.

The following is my code.

@
// main.cpp//
#include <QApplication>
#include "mainwindow.h"
#include "rgbdlg.h"
int main(int argc,char **argv)
{

QApplication app(argc, argv);
MainWindow *mwin =new MainWindow();
mwin->show();
return app.exec();
}

@

@
//MainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtGui>
#include "rgbdlg.h"

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

QAction *rgbFilterAct;

QMenuBar *menubar;

QMenu *fileMenu;
QMenu *processingMenu;

QLabel *imgLabel;
QScrollArea *scrollArea;
QImage imgsrc,imgdst;

double scaleFactor;

RGBDlg *rgbDlg;

signals:

public slots:
void open();
void save();
void quit();
void filterRGB();

};

#endif // MAINWINDOW_H

@

@
//MainWindow.cpp
#include "mainwindow.h"
#include "rgbdlg.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
this->setWindowTitle(tr("Filter image By Color "));

openAct = new QAction(tr("&Open..."),this);
quitAct = new QAction(tr("&Quit"),this);

rgbFilterAct = new QAction(tr("&Filter RGB"),this);

this->connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
this->connect(quitAct, SIGNAL(triggered()), this, SLOT(quit()));
this->connect(rgbFilterAct,SIGNAL(triggereed()),this,SLOT(filterRGB()));


fileMenu = new QMenu(tr("&File"),this);
fileMenu->addAction(openAct);
fileMenu->addAction(quitAct);

processingMenu= new QMenu(tr("&Processing"),this);
processingMenu->addAction(rgbFilterAct);

menubar=new QMenuBar;

menubar->addMenu(fileMenu);
menubar->addMenu(processingMenu);

imgLabel = new QLabel;
imgLabel->setBackgroundRole(QPalette::Base);
imgLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
imgLabel->setScaledContents(true);

scrollArea = new QScrollArea;
scrollArea->setBackgroundRole(QPalette::Dark);
scrollArea->setWidget(imgLabel);

this->setMenuBar(menubar);
this->setCentralWidget(scrollArea);

scaleFactor=1.0;
rgbDlg=NULL;

this->resize(800,600);
this->show();

}

void MainWindow::open(void)
{
QString fileName = QFileDialog::getOpenFileName(this,
tr("Open File"), QDir::currentPath());
if (!fileName.isEmpty()) {
QImage imgsrc(fileName);
if (imgsrc.isNull()) {
QMessageBox::information(this, tr("FilterImageByColor"),
tr("Cannot load %1.").arg(fileName));
return;
}
imgdst=imgsrc;
imgLabel->setPixmap(QPixmap::fromImage(imgdst));
scaleFactor=1.0;
imgLabel->resize(imgLabel->pixmap()->size());
return ;
}
return ;
}

void MainWindow::save(void)
{
return ;
}

void MainWindow::quit(void)
{
if(QMessageBox::Yes==QMessageBox::question(this,tr("FileterImageByColor"),
tr("Do you want to really quit program?"),
QMessageBox::Yes | QMessageBox::No,QMessageBox::No))
{
QApplication::quit();
}
return;
}

void MainWindow::filterRGB(void)
{
if(!rgbDlg) {
rgbDlg = new RGBDlg(this);
}
rgbDlg->exec();
return ;
}
@

@
//rgbdlg.h
#ifndef RGBDLG_H
#define RGBDLG_H

#include <QDialog>
#include <QtGUI>
class RGBDlg : public QDialog
{
Q_OBJECT
public:
RGBDlg(QWidget *parent = 0);

signals:

public slots:

};

#endif // RGBDLG_H

@

@
//rgbdlg.cpp
#include "rgbdlg.h"

RGBDlg::RGBDlg(QWidget *parent) :
QDialog(parent)
{
}

@

[gayu]

Think so u r using Qt4. Whether the code runs fine without showing any errors?
I checked the code whether it is running or not.
But,the code works fine for me.

[Sam]

Hi ,

Welcome to DEVNET,

If you check line 16 of mainwindow.cpp I think there is a mistake with

@this->connect(rgbFilterAct,SIGNAL(triggereed()),this,SLOT(filterRGB()));@

triggered() should be used ,spelling mistake/ you dont have any SIGNAL : triggereed() declaration for RGBDlg.

[Sam]

[quote author="gayu" date="1353394688"]Think so u r using Qt4. Whether the code runs fine without showing any errors?
I checked the code whether it is running or not.
But,the code works fine for me.[/quote]

The Project compiles n Runs successfully but for him the QAction is not working . Did you check with the requirements as I see if you click on Processing->Filter RGB it does not open RGBDlg, as there is a spelling mistake for the SIGNAL that he/she is trying to connect.

[gayu]

Whether the QAction is not working for him

[mybiandou]

Thank you, Sam

You are quire right.

I am sorry for my silly problem. It confused me for a week.

I really wish the meta object compiler can help much.

[Sam]

You are welcome,

bq. I am sorry for my silly problem.

No need, we all are here to learn :)

Kindly Edit your first post and prepend [Solved] to the title.

Happy Coding !!

[gayu]

In my project i also used the same QAction, but when compiling it show some errors.
Thats y i asked u about the QAction. Will u please tell me about that

[Sam]

[quote author="gayu" date="1353399435"]In my project i also used the same QAction, but when compiling it show some errors.
Thats y i asked u about the QAction. Will u please tell me about that[/quote]

What errors are you getting ?

[gayu]

ERROR
no matching function for call to ‘QAction::QAction(QString, QPixmap, QString, unsigned int, mainForm* const, const char [8])’

[Sam]

And how are you connecting the signals and slots ? Kindly share your code .

[gayu]

Ya sure
The following is the main.cpp file

@
#include <qapplication.h>
#include "mainform.h"

int main( int argc, char ** argv )
{
QApplication a( argc, argv );
mainForm w;
w.show();
a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
return a.exec();
}
@
The following code is somewhere in the mainform.cpp file

@
void mainForm::setupLanguageActions()
{

Q3ToolBar *tb = new Q3ToolBar( this );
tb->setLabel( "Language Actions" );
Q3PopupMenu *menu = new Q3PopupMenu( this );
menuBar()->insertItem( tr( "&Language" ), menu );

Q3Action *a;
a = new Q3Action( tr( "Tamil" ), tr( "&Tamil" ), Qt::CTRL + Qt::Key_Z, this, "langtamil" );
connect( a, SIGNAL( activated() ), this, SLOT( ChangeLangTamil() ) );
a->addTo( tb );
a->addTo( menu );

a = new Q3Action( tr( "Hindi" ), tr( "&Hindi" ), Qt::CTRL + Qt::Key_Y, this, "langhindi" );
connect( a, SIGNAL( activated() ), this, SLOT( ChangeLangHindi() ) );
a->addTo( tb );
a->addTo( menu );

}
@
And also for more actions..

[Sam]

Are you including the proper header files , Try including QObject header and build.
Also check for the proper signature of Q3Action class .

[gayu]

Might what the question i'm asking is silly, but please tell me
Whether Qt4 support QAction

[Sam]

[quote author="gayu" date="1353403125"]Might what the question i'm asking is silly, but please tell me
Whether Qt4 support QAction[/quote]

Ofcourse Qt4 support QAction ,you can have a look in "Porting to Qt 4":http://qt-project.org/doc/qt-4.8/porting4.html#qaction and "QAction":http://qt-project.org/doc/qt-4.8/qaction.html class.

But why are you still working in Qt 3 ?

[gayu]

So when using Q3ToolBar and Q3PopupMenu, their actions must be Q3Actions.
Otherwise the QAction itself is used right.