QT Connect Signal Slot and initialize in constructor

问题

I create connections between widged in the constructor and also initialize them. But the connect not working (inside the methode).

Code says alot:

MyApp::MyApp(QWidget *parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    // slider to spinbox
    connect(ui.slider, SIGNAL(valueChanged(int)), ui.spinbox, SLOT(setValue(int)));

    // SIGNAL To SLOT not called
    ui.slider->setValue(2);
    // I have to set this also:
    ui.spinbox->setValue(2);
}

回答1:

Have you tried doing

connect(ui.slider, SIGNAL(valueChanged(int)), this, SLOT(setValue(int)));

and have the slot setValue(int) update the spinbox when the slider is changed?

If you need it to go both ways, you will need to make two connections. One to connect a signal/slot to the slider, and one to connect a signal/slot to the spinbox.

Also, are you getting any errors?

来源：https://stackoverflow.com/questions/24635369/qt-connect-signal-slot-and-initialize-in-constructor