This functions show how to connect to a signal defined by a QMetaProperty. This is usefull to create editor for an object without knowing the object itself.

qt-automatic-property-connection.cpp

QWidget *ProjectWidget::_createBoolTreeEntry(QObject *cloudData, QMetaProperty property)
{
    auto checkbox = new QCheckBox(this);
    checkbox->setChecked(property.read(cloudData).toBool());

    connect(checkbox, &QCheckBox::clicked, [=](bool checked)
    {
        property.write(cloudData, checked);
    });

    auto checkboxMetaObject = checkbox->metaObject();
    int setCheckedMetaMethodIndex = checkboxMetaObject->indexOfMethod("setChecked(bool)");
    auto setCheckedMetaMethod = checkboxMetaObject->method(setCheckedMetaMethodIndex);
    connect(cloudData, property.notifySignal(), checkbox, setCheckedMetaMethod);

    return checkbox;
}

QWidget *ProjectWidget::_createIntTreeEntry(PointCloudData *cloudData, QMetaProperty property)
{
    QWidget* itemWidget = nullptr;

    if(property.isWritable())
    {
        auto slider = new QSlider(Qt::Horizontal, this);
        slider->setValue(property.read(cloudData).toInt());

        auto propertyInfo = cloudData->propertyInfo(property.name());

        slider->setMinimum(propertyInfo.MinValue);
        slider->setMaximum(propertyInfo.MaxValue);

        connect(slider, &QSlider::valueChanged, [=](int value)
        {
            property.write(cloudData, value);
        });

        itemWidget = slider;
    }
    else
    {
        auto label = new IntLabel(this);
        label->setValue(property.read(cloudData).toInt());

        itemWidget = label;
    }

    auto widgetMetaObject = itemWidget->metaObject();
    int setValueMetaMethodIndex = widgetMetaObject->indexOfMethod("setValue(int)");
    auto setValueMetaMethod = widgetMetaObject->method(setValueMetaMethodIndex);
    connect(cloudData, property.notifySignal(), itemWidget, setValueMetaMethod);

    return itemWidget;
}

QWidget *ProjectWidget::_createColorTreeEntry(QObject *cloudData, QMetaProperty property)
{
    auto colorBtn = new QPushButton(this);
    auto color = property.read(cloudData).value<QColor>();
    ColorUtils::setButtonColor(colorBtn, color);

    auto changeColorCallbackWrapper = [=](QColor newColor)
    {
        property.write(cloudData, newColor);
        ColorUtils::setButtonColor(colorBtn, newColor);
    };

    connect(colorBtn, &QPushButton::clicked, [=]
    {
        auto previousColor = property.read(cloudData).value<QColor>();

        QColorDialog colorDialog(color);
        connect(&colorDialog, &QColorDialog::currentColorChanged, changeColorCallbackWrapper);
        connect(&colorDialog, &QColorDialog::colorSelected, changeColorCallbackWrapper);

        if(!colorDialog.exec())
        {
            changeColorCallbackWrapper(previousColor);
        }
    });

    return colorBtn;
}

QWidget *ProjectWidget::_createTextEntry(QObject *cloudData, QMetaProperty property)
{
    auto label = new QLabel(this);
    label->setText(property.read(cloudData).toString());

    if(property.hasNotifySignal())
    {
        auto labelMetaObject = label->metaObject();
        int setTextMetaMethodIndex = labelMetaObject->indexOfMethod("setText(QString)");
        auto setTextMetaMethod = labelMetaObject->method(setTextMetaMethodIndex);        
        connect(cloudData, property.notifySignal(), label, setTextMetaMethod);
    }

    return label;
}