QPushButton binding does not work without lambda keyword

[daweed]

Hello,
i am facing a problem that i don't understand why it happen.

When binding a QPushButton in a subclass method of my project

#! python3
# -*- coding: utf-8 -*-

import sys
import re

from PySide2.QtWidgets import *
from PySide2.QtCore import Qt, QRect, QCoreApplication
from PySide2.QtGui import QIcon, QFont, QPixmap

from FGIntMngtUI.FGIntMngtDeviceTab import Ui_FGIntMngtDeviceTab
from FGIntMngtUI.FGIntMngtMCP23017Tab import Ui_FGIntMngtMCP23017Tab

class FGIntMngtDevice():
    def __init__(self, item: QTreeWidgetItem, objectTab: QTabWidget, displayLog: QTextEdit):
        self.item = item
        self.devicename = self.item.text(0)
        self.deviceid = self.item.text(1)
        self.deviceaddr = self.item.text(2)
        self.devicetype = self.item.text(3)
        self.objecttab = objectTab
        self.displaylog = displayLog
        self.devicetabValueSteelSheet = "QLabel { font-size:12pt; }"

    ##### ##### ##### ##### ##### ##### ##### #####
    # Self String
    ##### ##### ##### ##### ##### ##### ##### #####
    def __str__(self):
        return "Device Objects Managements (FGIntMngtDevice Class)"
    
    def updateDevice(self):
        self.displaylog.append("test")
        print("test")

    def getDevice(self):
        self.objecttab.clear()
        self.displaylog.append("Getting Device .... {}".format(type(self.objecttab)))
        self.displaylog.append("Device Name {}".format(self.devicename))
        self.displaylog.append("Device Type {}".format(self.devicetype))
        self.displaylog.append("Device Addr {}".format(self.deviceaddr))
        self.currenttab = Ui_FGIntMngtDeviceTab()
        self.currenttab.setupUi(self.objecttab)
        self.currenttab.DeviceApplyBtn.clicked.connect(self.updateDevice)
        #self.currenttab.DeviceApplyBtn.clicked.connect(lambda: self.updateDevice())
        self.currenttab.DeviceTypeValue.setStyleSheet(self.devicetabValueSteelSheet)
        self.currenttab.DeviceIdValue.setStyleSheet(self.devicetabValueSteelSheet)
        self.currenttab.DeviceIdValue.setText(self.deviceid)
        self.currenttab.DeviceAddrValue.setStyleSheet(self.devicetabValueSteelSheet)
        self.currenttab.DeviceAddrValue.setText(self.deviceaddr)
        self.currenttab.DeviceNameValue.setStyleSheet(self.devicetabValueSteelSheet)
        self.currenttab.DeviceNameValue.setText(self.devicename)
        index = self.currenttab.DeviceTypeValue.findText(self.devicetype, Qt.MatchFixedString)
        if index >= 0:
            self.currenttab.DeviceTypeValue.setCurrentIndex(index)

the line binding the button [ this does not work ]

self.currenttab.DeviceApplyBtn.clicked.connect(self.updateDevice)

but if i use the following code it work

self.currenttab.DeviceApplyBtn.clicked.connect(lambda: self.updateDevice())

I don't understand why i am oblige to use lambda here.
The main scripts create the GUI with a .py file create from a .ui file designed with Qt Designer.
The main scripts call some other class and ui class

If needed i can post more code

Regards

Daweed

[SGaist]

Hi and welcome to devnet,

What version of PySide2 are you using ?
How did you install it ?

[daweed]

Hello

I am using pyside2 5.13.0
and install it with the pip command

pip3 install PySide2
i am using python 3.7.2

I am not sure that it's a pyside issue as if i am using for example the code to clear the displayLog widget [ QTextEdit object ] and no error are raised. The method updateDevice seems to just not be executed.

self.currenttab.DeviceApplyBtn.clicked.connect(self.displayLog.clear)

the binding work.

I am asking myself if there is not a problem when "propagating" the variable [ QTabWidget ]. I'm probably doing something wrong but I can not understand what :)

Here a view of the GUI

The main windows is create in the main script

#! python3
# -*- coding: utf-8 -*-

import sys
import re
import socket
from PySide2.QtWidgets import *
from PySide2.QtCore import Qt, QRect, QCoreApplication
from PySide2.QtGui import QIcon, QFont, QPixmap

# FarmerSoft Tools Lib
from FGIntMngt.FGIntMngtConfig import FGIntMngtConfig
from FGIntMngt.FGIntMngtClient import FGIntMngtClient
from FGIntMngt.FGIntMngtObject import FGIntMngtObject

# FGIntMngt UI Windows & Widgets
from FGIntMngtUI.FGIntMngtMain import Ui_MainWindow
from FGIntMngtUI.About import Ui_About

class MainWindow(QMainWindow, Ui_MainWindow):
    ##### ##### ##### ##### ##### #####
    ##### MainWindow Constructor
    ##### ##### ##### ##### ##### #####
    def __init__(self):
        super(MainWindow, self).__init__()

        ##### ##### ##### ##### ##### ##### ##### #####
        ##### Main Windows Initialisation
        ##### ##### ##### ##### ##### ##### ##### #####
        self.setupUi(self)

        ##### ##### ##### ##### ##### ##### ##### #####
        ##### Properties
        ##### ##### ##### ##### ##### ##### ##### #####
        
        ##### ##### ##### ##### ##### ##### ##### #####
        ##### Steel Sheet
        ##### ##### ##### ##### ##### ##### ##### #####
        self.LabelSteelSheet = "QLabel { font: bold; }"
        self.conSteelSheet = "QLabel { font: bold; color: green; }"
        self.disconSteelSheet = "QLabel { font: bold; color: red; }"

        ##### FGIntMngt Configuration
        self.fgintmngtconfig = FGIntMngtConfig()
        self.fgintmngtconfig.readConfig('treeobjects.ini')
        self.treeBranches = self.fgintmngtconfig.loadBranch(self.objectsTree)
        self.logDisplay.clear()
        
        ##### FGIntMngt Object Tree
        self.fgintmngtobjects = FGIntMngtObject(self.objectsTree, self.objectTab, self.logDisplay)

        ##### FGIntMngt TCP CLient
        self.fgintmngtclient = FGIntMngtClient()

        ##### Tab Module
        
        ##### ##### ##### ##### ##### ##### ##### #####
        ##### Slots And Signals
        ##### ##### ##### ##### ##### ##### ##### #####
        
        ##### Main Window
        ##### ##### Menu File
        self.actionQuit.triggered.connect(self.quitGui)

        ##### ##### Menu Configuration
        self.actionReadDevices.triggered.connect(self.readDevices)
        
        ##### ##### Menu Help
        self.actionAbout.triggered.connect(self.showAbout)

        ##### Status Frame Binding
        self.connexionButton.clicked.connect(self.connectFGIntSrv)
        
        ##### Tree Frame Binding
        self.objectsTree.itemClicked.connect(self.fgintmngtobjects.getObject)
        
    def quitGui(self):
        self.fgintmngtclient.setConnStatus(0)
        self.close()

    def showAbout(self):
        ##### About UI
        self.about = QWidget()
        self.ui_about = Ui_About()
        self.ui_about.setupUi(self.about)
        self.about.show()

    def connectFGIntSrv(self):
        self.logDisplay.clear()
        self.logDisplay.append("Connexion Parameters : {}:{}".format(self.fgintmngtclient.getFGIntHost(), self.fgintmngtclient.getFGIntPort()))
        if self.fgintmngtclient.getConnStatus() == 0:
            self.logDisplay.append("ready to connect")
            if self.fgintmngtclient.connectServer() == 1:
                self.logDisplay.append("Connection OK")
                self.connstatusValue.setText('Connected')
                self.connstatusValue.setStyleSheet(self.conSteelSheet)
                self.connexionButton.setText('Disconnect')
                data = self.fgintmngtclient.sock.recv(1024).decode("utf-8")
                self.logDisplay.append(data)
                self.readDevices()
            else:
                self.logDisplay.append("Connection Failed")
                self.fgintmngtclient.setConnStatus(0)
                self.connstatusValue.setText('Not Connected')
                self.connexionButton.setText('Connect')
                self.connstatusValue.setStyleSheet(self.disconSteelSheet)
        else:
            self.logDisplay.append("Disconnection")
            self.fgintmngtclient.setConnStatus(0)
            self.connstatusValue.setText('Not Connected')
            self.connexionButton.setText('Connect')
            self.connstatusValue.setStyleSheet(self.disconSteelSheet)
            self.fgintmngtclient.sendCmd("exit\n", 1024)

    def readDevices(self):
        self.logDisplay.clear()
        self.logDisplay.append("Nb d elements a purger : {}".format(self.treeBranches['Devices']['widget'].childCount()))
        if self.treeBranches['Devices']['widget'].childCount() > 0:
            self.logDisplay.append("Cleaning Devices Branch ...")
            for i in reversed(range(self.treeBranches['Devices']['widget'].childCount())):
                self.treeBranches['Devices']['widget'].removeChild(self.treeBranches['Devices']['widget'].child(i))
        if self.fgintmngtclient.getConnStatus() == 1:
            self.logDisplay.append("Listing devices from FG interface ...")
            datatab = self.fgintmngtclient.sendCmd("show devices\n", 1024).splitlines()
            #self.logDisplay.append("datatab Type : {}".format(type(datatab)))
            #self.logDisplay.append("datatab Length: {}".format(len(datatab)))
            devicenum = 1
            devices = datatab[0][1:-1].split(',')
            for device in devices:
                for deviceaddr in device.split(' '):
                    if re.match("^\dx\d{2}$", deviceaddr[1:-1]):
                        self.logDisplay.append("New Device Found : {} at address {} Type : {}".format('device' + str(devicenum).zfill(2), deviceaddr[1:-1], 'Device'))
                        item = QTreeWidgetItem(self.treeBranches['Devices']['widget'], 0)
                        item.setText(0, 'device' + str(devicenum).zfill(2))
                        item.setText(1, 'item' + str(devicenum).zfill(2))
                        item.setText(2, deviceaddr[1:-1])
                        item.setText(3, 'Device')
                        item.setText(4, 'Unknow')
                        devicenum += 1
        else:
            self.logDisplay.append("Not Connected")



##### ##### ##### ##### ##### ##### ##### #####
##### Main Application Definition & Execution
##### ##### ##### ##### ##### ##### ##### #####
def main():
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

When clicking on an item in the QTreeWidget, an object is creating with a FGIntMngtObject Class

self.objectsTree.itemClicked.connect(self.fgintmngtobjects.getObject)

The FGIntMngtObject Class

#! python3
# -*- coding: utf-8 -*-

import sys

from PySide2.QtWidgets import *
from PySide2.QtCore import Qt, QRect, QCoreApplication
from PySide2.QtGui import QIcon, QFont, QPixmap

from FGIntMngt.FGIntMngtDevice import FGIntMngtDevice

class FGIntMngtObject():
    def __init__(self, treeWidget: QTreeWidget, objectTab: QTabWidget, displayLog: QTextEdit):
        super(FGIntMngtObject, self).__init__()
        self.treeWidget = treeWidget
        self.objecttab = objectTab
        self.displaylog = displayLog

    ##### ##### ##### ##### ##### ##### ##### #####
    # Self String
    ##### ##### ##### ##### ##### ##### ##### #####
    def __str__(self):
        return "FGIntMngtObject Class"

    ##### ##### ##### ##### ##### ##### ##### #####
    # Class Methods
    ##### ##### ##### ##### ##### ##### ##### #####
    def getObject(self):
        # Debug Printing #
        #print("Getting Object from Tree ...")
        #print("Current Item : {}".format(self.treeWidget.currentItem()))
        #print("Item have {} Column(s) and {} Child(s)".format(self.treeWidget.currentItem().columnCount(), self.treeWidget.currentItem().childCount()))
        # End Debug Printing #
        if self.treeWidget.indexOfTopLevelItem(self.treeWidget.currentItem().parent()) != -1: # Check if obj is not a top level branch
            #for c in range(self.treeWidget.currentItem().columnCount()):
            #    print("Column {} Value {}".format(c, self.treeWidget.currentItem().text(c)))
            if self.treeWidget.currentItem().text(3) == 'Device':
            	#devicename, deviceaddr, devicetype, objectTab
                element = FGIntMngtDevice(
                	self.treeWidget.currentItem(),
                    self.objecttab,
                    self.displaylog
                    )
                print("Nom de l'élément : {}".format(element.devicename))
                element.getDevice()

    def updObject(self):
        print("Updating Object ....")

And from that if the QTreeWiddgetItem is a 'Device' type a Device Object will be generated and the QTabWidget is populate via the FGIntMngtDevice Class

Hopping that will help

If needed , i can post UI python files

Regards

[SGaist]

Can you rather post a minimal example that shows that behaviour ?

[Sia1s]

This post is deleted!