Signal is not emitted

gabor53

Hi,
I have the following code:
imagecorrecctbutton.h:

 signals:
  void selectedFileChanged(QString& fileName);

imagecorrectbutton.cpp:

void ImageCorrectButton::setSelectedFile(const QString& val) {
  if(m_selectedFile == val) {
    return;
  }
  m_selectedFile = val;
  QSignalSpy spy(ImageCorrectButton::m_mainButton, SIGNAL(selectedFileChanged (QString)));

  if(!m_selectedFile.isEmpty()) {
    m_mainButton->setText(QString());
    m_mainButton->setIcon(QIcon(m_selectedFile));
    m_mainButton->setIconSize(QSize(100, 100));
    emit selectedFileChanged(m_selectedFile);

    //checking signal
    QCOMPARE(spy.count(), 1);
    QList<QVariant> arguments = spy.takeFirst();
    QVERIFY(arguments.at(0).toBool() == true);
  }
}

Every time I get the following message:
QSignalSpy: No such signal: 'selectedFileChanged(QString)'
QObject::connect: No such signal ImageCorrectButton::selectedFileChanged(QString) in ..\Folkfriends_1_0\mydelegate.cpp:137
What am I doing wrong when I'm trying to emit the signal?
Thank you for your help.

dheerendra

selectedFileChanged Signal is presented in imagecorrectbutton class. U r giving argument as main button. Hence the issue. Please correct the same. It should work.

gabor53

@dheerendra
I changed the connect:

      connect(ImageCorrectButton, SIGNAL(selectedFileChanged(QString)), this, SLOT(fileChanged()));

Now it says
"QObject::connect: No such signal ImageCorrectButton::selectedFileChanged(QString) in ..\Folkfriends_1_0\mydelegate.cpp:137

The signal is in imagecorrectbutton:

emit selectedFileChanged(m_selectedFile);

What I am still missing?

beecksche

@gabor53
In your signal you use a reference QString&

void selectedFileChanged(QString& fileName);

Maybe you have to add this in the connection.

But, i think references in signals are not a good choice, i normally use copies or const references, like

void selectedFileChanged(QString fileName);

or

void selectedFileChanged(const QString& fileName);

dheerendra

as pointed out already by the previous post, it is is the issue of signature mismatch. Please correct signal signatures. it should work.

jsulm

@gabor53 You have to provide a pointer to ImageCorrectButton instance instead of class itself when using connect():

// This is done somewhere in your code:
ImageCorrectButton *imageCorrectButton;
...
imageCorrectButton = new ImageCorrectButton();
...
connect(imageCorrectButton, SIGNAL(selectedFileChanged(QString)), this, SLOT(fileChanged()));

connect connects two instances: you cannot connect a class to something.