Replacing deprecated QtSignalMapper class to forward Signals in Qt5

Question

I have this code which makes a mdi window written for Qt 4:

class MdiWindow : public QMainWindow
{
    Q_OBJECT
public:
    MdiWindow( QWidget *parent = nullptr)         


        

Answer 1

Previously you used QSignalMapper::setMapping() to make sure that you'd be sent data you need when the SLOT() was called. Now you can just encapsulate this logic inside a lamba, so if you did (like in Qt example):

     for (int i = 0; i < texts.size(); ++i) {
         QPushButton *button = new QPushButton(texts[i]);
         connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
         signalMapper->setMapping(button, texts[i]);
     }
     connect(signalMapper, SIGNAL(mapped(const QString &)),
             this, SIGNAL(clicked(const QString &)));

you can now do (somewhat):

     for (int i = 0; i < texts.size(); ++i) {
         QPushButton *button = new QPushButton(texts[i]);
         connect(button, &QPushButton::clicked, [=]() {
             emit clicked(texts[i]);
         });
     }

If the setMapping() is not being used, then it probably could have been connected directly to a SLOT() already.