QDoubleValidator is not working?

Question

I'm trying to apply validator in a line edit box in Qt 4.2 and it is not working:

 QDoubleValidator *haha= new QDoubleValidator(this);
 haha->setBottom(0.00);
 haha->setDecimals(2);
 haha->setTop(100.00); 
 get_line_edit()->setValidator(haha);

or

 QDoubleValidator *haha= new QDoubleValidator(0.00,100.00,2,this);

Neither way, I can still enter what ever value I want.

But if I switch to QIntValidator, it works!

So I went onto Google and did a bit search, and many people used to having the same issue. Is it a bug? or there should be some other set up I should do?

Answer 1

Just tripped over this one. Try setting the QDoubleValidator notation to:

doubleValidator->setNotation(QDoubleValidator::StandardNotation);

Answer 2

The validator documentation says that it returns "Intermediate" from "validate" when the input is an arbitrary double but out of range.

You need to distinguish intermediate input and the final input the user wants to submit by use of a line edit control (e.g. by emitting the "returnPressed" signal). If the user typed "10000" that is still a valid intermediate input for a number between 0 and 100 because the user can prefix this input with "0.".