Re: [tauruslib-devel] [Sardana-users] Validate input of TaurusLabelEditRW

[Carlos M. F. T. <cf...@ce...>]

Hi Grzegorz,
The actual TaurusLabelEditRW can not allow this "feature", the method 
setValidator is there because it comes from Qt widgets.
TaurusLabelEditRW uses the TaurusLineEdit as writewidget and it 
overwrites the used validator in each event.
TaurusLineEdit creates the validator each time attending the attribute 
range, that is the reason because your solution does not work.

That I propose you is an ugly workaround :

The workaround consists in create your own TaurusLineEdit widget and 
overwrite the "_updateValidator" method.

Unfortunately these classes are not documented so I hope  this example 
can help you.

    import sys

    from taurus.external.qt import QtGui

    from taurus.qt.qtgui.application import TaurusApplication
    from taurus.qt.qtgui.input import TaurusValueLineEdit
    from taurus.qt.qtgui.compact import TaurusLabelEditRW


    class MyTaurusValueLineEdit(TaurusValueLineEdit):
         # Reimplement _updateValidator method
         def _updateValidator(self, attrinfo):
             pass


    app = TaurusApplication()

    f = TaurusLabelEditRW(writeWClass=MyTaurusValueLineEdit)
    f.model = 'sys/tg_test/1/double_scalar_w'
    validator = QtGui.QDoubleValidator(10, 20, 5)
    f.writeWidget.setValidator(validator)

    f.show()
    sys.exit(app.exec_())


The other option is somehow in your widget update dynamically the range 
of your attribute.


Could you create a ticket in taurus [1] to discuss a proper solution for 
taurus?

[1] https://sourceforge.net/p/tauruslib/tickets/


Best,
Carlos


On 07/27/2016 07:36 PM, Grzegorz Kowalski wrote:
> Hello,
> I have a problem with TaurusLabelEditRW, I need to validate its input to
> only set values inside certain range, but I don't know how to stop it
> from setting an attribute value when it's invalid.
>
> My first try was to use QDoubleValidator with TaurusValueLineEdit that
> is a part of RW widget, but it seems to ignore validator despite it's
> based on QLineEdit.
>
> code:
> rw = TaurusLabelEditRW()
> validator = QDoubleValidator(100, 300, 5)
> for c in rw.children():
> 	if c.__class__.__name__ == "TaurusValueLineEdit":
> 		c.setValidator(self.validator)
>
> Second try was to connect to returnPressed signal of the line edit, and
> check the value, but I have no idea on how to prevent setting invalid
> value to the attribute.
>
> The range can't be just Tango attribute's max and min values because it
> is dependent on other parameters.
> I'm using Taurus 3.7.0.
>
> Thank you for any help!