QWidget not response on ComboBox action

nebulaekg

Hi, I am new to Qt. I encountered a problem related to QWidget. I setup a QWidget, which has a ComboBox selector. My goal is to use this selector to control some behavior in the main app. I initiated the QWidget in the main ui, but when I change the currentText of the ComboBox, it seems that it does nothing at all. Below is my code:

surfaceproperty.h:

namespace Ui {
class SurfaceProperty;
}

class SurfaceProperty : public QWidget
{
    Q_OBJECT

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

public slots:
    void on_selectorSurfaceColormap_currentTextChanged(const QString &arg1);

public:
    Ui::SurfaceProperty *uisp;
};

surfaceproperty.cpp:

#include "surfaceproperty.h"
#include "ui_surfaceProperty.h"

SurfaceProperty::SurfaceProperty(QWidget *parent) :
    QWidget(parent),
    uisp(new Ui::SurfaceProperty)
{
    uisp->setupUi(this);
}

SurfaceProperty::~SurfaceProperty()
{
    delete uisp;
}

void SurfaceProperty::on_selectorSurfaceColormap_currentTextChanged(const QString &arg1)
{
           qInfo() << arg1;
}

Part of main app here:

    QWidget *t = new QWidget;
    uif->uisp->setupUi(t);
    t->show();
    t->setWindowTitle("Surface Properties");
    t->setAttribute(Qt::WA_QuitOnClose, false);
    uif->uisp->selectorSurfaceColormap->setCurrentText("test");

where uif is a SurfaceProperty* I defined here in the main app.

I did not post my ui file here.

Basically, I expect that when this part of the main app is called, a widget window appears, and when the ComboBox's currentText is changed, I can get a qInfo() output at the cmd (I build it under Linux). But I only get a widget window when this part is called. I did not see the qInfo() output at all, meaning the ComboBox part is not functional at all.

Could anyone indicate what is the problem? Did I miss some signal & slot thing?

Thank you very much!

Christian Ehrlicher

Please do not use the auto-connect feature but connect the signals/slots by your own. Maybe you've a type on the member name (selectorSurfaceColormap) so the auto-connect feature can not find the slot.

nebulaekg

@Christian-Ehrlicher Hi, Christian, thanks for the reply but I am a little confused. Why the auto-connect feature is not encouraged? Is this true for all windows or only qwidget? I have many auto-connects in the main app, they all work very well. I also did not quite get it on this line: "...you've a type on the member name". Could you indicate? Thanks a lot!

Christian Ehrlicher

I said 'Maybe you've a typo...'
The problem with auto-connect is that you can not be sure if it is really connected (e.g. when there is a typo somewhere in the functions signature or the ui element name) and it easily breaks (e.g. when renaming an ui element).