Pass signals between classes in PyQt

deranjer

Hi, I am new to python and PyQt both, so stuck when trying to update my main screen when exiting an "exit screen".

I have two separate classes in my python file (code example typed below)

First Class = Main GUI with labels
I have a function in the first class (labelUpdate) to update the labels on my GUI to values in an INI file.

Second Class = Edit Screen, to change values that will update Main Gui
I want to CALL the function (labelUpdate), even though I am in the second class, not the first class. I need to do this to update the values on the first/main GUI.

I looked extensively at signals, but don't see how to use signals across different classes! Is that possible?

@class mainScreen(QtGui.QDialog, Ui_mainScreen):
def init(self, parent=None):
QtGui.QWidget.init(self, parent)
self.setupUi(self)

    #Reading to config and assigning the values to our txt labels
    self.labelUpdate()

    self.editWindow = None
    

def labelUpdate(self): #NEED to run this when I hit OKAY on my edit screen!
    config = configparser.ConfigParser()
    config.read('netSettings.ini')
    #udating the labels from the config file
    for i in config.sections():
        num = "%s" % i
        if num in config.sections():
            print("Running Label UPDATE!",  i)
            print("SElf",  self)
            apiLabel = "self.apiLabel%s.setText(config[num]['api'])" % i
            exec&#40;apiLabel&#41;
            self.apiLabel1.setText(config[num]['api'])
            ipLabel = "self.ipLabel%s.setText(config[num]['ip address'])" % i
            exec&#40;ipLabel&#41;
            gatewayLabel = "self.gatewayLabel%s.setText(config[num]['gateway'])" % i
            exec&#40;gatewayLabel&#41;

#connecting out editscreen python file as a class
class editScreen(QtGui.QDialog, Ui_Dialog):
def init(self, parent=None):
QtGui.QDialog.init(self, parent)
self.setupUi(self)
self.editWindow = None

    okayButton = self.buttonBox.button(QtGui.QDialogButtonBox.Ok)
    okayButton.clicked.connect(self.okaySignal)
def okaySignal(self):
    print("Saving Data to slot ",  editButtonNumber)
    num = editButtonNumber
    config = configparser.ConfigParser()
    #Reading the file so we don't overwrite entire file with one entry
    config.read('netSettings.ini')
    config[num] = {'API': self.lineEditAPI.text(), 
                          'IP ADDRESS': self.lineEditIP.text(),   
                          'SUBNET MASK': self.lineEditMask.text(), 
                          'GATEWAY': self.lineEditGateway.text(), 
                          'DNS1': self.lineEditDNS1.text(), 
                          'DNS2': self.lineEditDNS2.text() }
    configfile = open('netSettings.ini',  'w')
    config.write(configfile)
    configfile.close()  #Done with file, closing it  
    print("Closing Edit Window")
    #NEED to call labelupdate from right here.. not sure how to do with signals across classes!
    self.close()@

b1gsnak3

In C++ it is possible, it should be in python as well... However I am not sure on how you can do it... but from what I understand, you are calling the edit screen to show from your main window (no?) if so, you can connect (for example) @self.editWindow.nameOfSignal.connect(self.slotName) // not sure if is correct@

deranjer

Actually, when I hit the "OK" Button on my edit dialog, I want the information on my Main screen to update with the new information. Since they are in separate classes, not sure how to communicate between classes.

Actually, I think I figured out how to do it, although not sure if it is the correct way to do it.

At the end of the okaySignal function in my editScreen class I added this after self.close():

@self.mainScreen = mainScreen(self)
self.mainScreen.close()
self.mainScreen.show()
self.mainScreen.labelUpdate()@

This works.. I think it kept the old screen up, so closing and opening it works great, although since the labelUpdate() is already run at init, may not need the last line...

deranjer

Well.. that doesn't work, just adds another screen on top of the old that has the correct info... Someone else finally pointed out the solution to me though, and I realize that I needed to post the full code, so it is available here: http://pastebin.com/GFHvrbeB

The issue is I call the edit window with:

@ def editButton(self, editButtonNum):
self.editWindow = None
global editButtonNumber
editButtonNumber = editButtonNum
if self.editWindow is None: #if Edit sceen not showing already
self.editWindow = editScreen(self) #Create out editwindow from our class editscreen
self.editWindow.show()@

So I can still connect to it from there.

So I added the following line:

@ self.editWindow.updated.connect(self.labelUpdate)@

And then added two lines to editScreen():
@updated = QtCore.pyqtSignal()@ #Added right after class declaration

@self.updated.emit()@ #Added right before self.close() in okaySignal()

Now everything works great.