Make messageBar critical messages permanent

Question

The default for messages generated with self.iface.messageBar().pushCritical() is to remain on screen for a set duration. I would like them to keep being displayed as long as the user has not closed them by clicking on "x", but I don't know how to do that.

I also tried using pushMessage()instead of pushCritical(), as it allows you to specify a duration and thus could make the message "permanent" if I specified a very long duration, but I can't get it to work. The instruction

self.iface.messageBar().pushMessage(u'Error : ', u' My error message.', level=QgsMessageBar.CRITICAL, duration=999)

gets me the following error in the console : NameError: global name 'QgsMessageBar' is not defined. I don't understand what the problem is, I used from PyQt4.QtGui import * at the beginning of my script...

Answer 1

QgsMessageBar comes from the qgis.gui module, not from PyQt4.QtGui :)

So you could use something like the following:

from qgis.gui import QgsMessageBar

self.iface.messageBar().pushMessage(u'Error : ', u' My message.', level = QgsMessageBar.CRITICAL, duration=0)

Where the integer 0 indicates a no timeout (i.e. no duration).