online changeable Qlabel or qlineedit

[TahaLotfi]

how can i have a QLabel or Qlineedit that i can change its text online to new number.
for example first value is "0" when i set the text to 432.1 (in Qlabel or Qline ) in gui the new number show in command line.
thanks

[SGaist]

Hi,

If it's a number input you should consider using QSpinBox or QDoubleSpinBox.

As for your question, do you mean connecting your widget a slot that would do something like qDebug() << newValue ?

[TahaLotfi]

@SGaist
thanks
my inputs are number. but i want to use Qlabel or Qlineedit to get float number from user and user can change value online. when value change , show it by qDebug()...

[SGaist]

Then QDoubleSpinBox is what you want.

As for the rest, please read the Signals And Slots chapter of Qt's documentation.

[mrjj]

Hi
And when you read about signals and slots so you know what's it about,
you can use the help to get the connect statement as its a bit funky due as there are 2 versions. (overloads)

https://doc.qt.io/qt-5/qdoublespinbox.html#valueChanged

connect(ui->doubleSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged),
    [=](double d){
       qDebug() << d;
   });

This uses a lambda for the slot.

it will print in the Application output.

[TahaLotfi]

hi thank's
How can i use float Numbers?

[mrjj]

@TahaLotfi
Hi
it already uses doubles.
so that should also work for float type.