Different types in connections
That is more a question a about best design using the qt classes. I have done a program and several times I have to perform some conversion from string(QLineEdit for example) to double and vice versa. I would like to know from more experience programmer if it is better to use QVariant to all basic types or you use other approach.
Generally when you have to do such conversions often, the first question that comes to my mind is: am I using the right tool ?
For number input, you should rather use QSpinBox or QDoubleSpinBox, if you need another type you can even subclass QAbstractSpinBox.
Hope it helps