[PyQt] signal propagating

[Matt Newell]

On Tuesday 28 September 2010 14:00:13 Eric Frederich wrote:
> Hello,
> 
> Here's a stripped down example of my problem.
> I have a group of widgets that I keep together with a class called
> MyWidgetGroup.
> It holds a line edit and a label which together have a meaning (getMeaning)
> but by themselves mean nothing.
> 
> I need to make connections to a method so it'll get called whenever the
> widget's text changes but I don't want the reference to the line edit, I
> want the reference to the widget group (so I can getMeaning on it).
> 
> To do this I wound up creating a dummy method that just propagates the
> signal so that it comes from the widget group instead of just the line
> edit. I have a bad feeling about this.  There must be a better way to do
> this right?
> Can this be accomplished by connecting signals to signals?
> 

Yes. Define your signal inside your class, then connect the line edit's signal 
to it.

Here's a complete working example.


from PyQt4.QtGui import *
from PyQt4.QtCore import *

class MyWidgetGroup(QWidget):
	theValueChanged = pyqtSignal()
	
	def __init__(self, parent=None):
		super(MyWidgetGroup, self).__init__(parent)
	
		self.myLabel = QLabel(self)
		self.myEdit  = QLineEdit(self)

		self.myEdit.textChanged.connect( self.theValueChanged )

		self.theValueChanged.connect( self.valueChangedSlot )

	def valueChangedSlot(self):
		print "It works"

app = QApplication([])
widget = MyWidgetGroup()

widget.show()

app.exec_()




Matt


PS  Next time it would be nice if your example was runnable.