QMessageBox not working

[RamanSMann]

hi i am new to PyQt and learning from a tutorial. i am using Qt5. i am not able to get popup window when i click my push button. thank you in advance

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import  QMessageBox
import sys

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)```

        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.button = QtWidgets.QPushButton(self.centralwidget)
        self.button.setGeometry(QtCore.QRect(70, 90, 641, 341))
        self.button.setIconSize(QtCore.QSize(40, 40))
        self.button.setObjectName("button")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

        self.button.clicked.connect(self.show_popup)
        
    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "Click me"))
        self.button.setText(_translate("MainWindow", "Press me"))

    def show_popup(self):
        msg = QMessageBox()
        msg.setWindowTitle("Lame")
        msg.setText("your computer is Lame. Thank you")
        msg.setIcon(QMessageBox.Warning)
        msg.standardButtons(QMessageBox.Ok|QMessageBox.Abort|QMessageBox.Ignore)
       x = msg.exec_()
        
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

[RamanSMann]

i found it

[sierdzio]

I guess you need to use msg.show().

[Borbixxx]

I am also working with PyQt5 and trying to integrate QMessageBox in my project.
In my case I built a robot control interface, and I want to trigger popups when something goes wrong (like empty list or error in queue).
But I am not sure if I’m using QMessageBox.warning correctly inside my methods.

self.BtSaveToFileEmergency.clicked.connect(self.SaveEmergency)
self.BtConveyer.clicked.connect(self.Conveyer)
self.SliderTrack.valueChanged.connect(self.move_track)
self.BtAddObject.clicked.connect(self.add_from_combo)
self.BtDeleteLast.clicked.connect(self.delete_last)
self.BtClearList.clicked.connect(self.clear_session)
self.BtRunSession.clicked.connect(self.run_session)

self.takeCell = [0.6, -0.1, 0.32]
self.takeTrack = 1.2

self.cells = {
    1:[0.5,-0.05,0.56], 2:[0.38,-0.25,0.32], 3:[0.41,-0.25,0.32], 4:[0.44,-0.25,0.32],
    5:[0.35,-0.10,0.32], 6:[0.38,-0.10,0.32], 7:[0.41,-0.10,0.32], 8:[0.44,-0.10,0.32],
    9:[0.35, 0.05,0.32],10:[0.38, 0.05,0.32],11:[0.41, 0.05,0.32],12:[0.44, 0.05,0.32],
}
self.cellTrack = {1:1,2:1,3:1,4:1,5:0.7,6:0.7,7:0.7,8:0.7,9:0.4,10:0.4,11:0.4,12:0.4}
self.rejectCell = [0.50, 0.20, 0.32]; self.rejectTrack = 0.9

self.allowed = {'Box1':[1,2,3,4], 'Box2':[5,6,7,8], 'Box3':[9,10,11,12]}
self.occupied = {i: False for i in range(1,13)}

self.session = []
self.session_model = QtCore.QStringListModel()
self.LVSession.setModel(self.session_model)

def _refresh_session(self):
    self.session_model.setStringList([f"{i+1}. {x}" for i,x in enumerate(self.session)])

def add_from_combo(self):
    if not hasattr(self,'CBObjects'): return
    cat = self.CBObjects.currentText().strip()
    if cat in ('Box1','Box2','Box3','Reject'):
        self.session.append(cat); self._refresh_session(); self.add_log(f"Add: {cat}")

def delete_last(self):
    if self.session: 
        rem = self.session.pop(); self._refresh_session(); self.add_log(f"Delete: {rem}")

def clear_session(self):
    self.session.clear(); self._refresh_session(); self.add_log("Clear list")

def _pick_and_place(self, dst_pos, dst_track):
    up = 0.10
    rx, ry, rz = getattr(self,'DEFAULT_RX',0.0), getattr(self,'DEFAULT_RY',0.0), getattr(self,'DEFAULT_RZ',0.0)

    self.robot.addMoveToPointL([Waypoint([0.5, -0.05, 0.57, rx, ry, rz])])
    self.robot.addLinearTrackMove(self.takeTrack)
    self.robot.addMoveToPointL([Waypoint([*self.takeCell[:2], self.takeCell[2]+up, rx,ry,rz])])
    self.robot.addMoveToPointL([Waypoint([*self.takeCell, rx,ry,rz])])
    self.robot.addToolState(1)
    self.robot.addMoveToPointL([Waypoint([*self.takeCell[:2], self.takeCell[2]+up, rx,ry,rz])])

    self.robot.addLinearTrackMove(dst_track)
    self.robot.addMoveToPointL([Waypoint([dst_pos[0], dst_pos[1], dst_pos[2]+up, rx,ry,rz])])
    self.robot.addMoveToPointL([Waypoint([*dst_pos, rx,ry,rz])])
    self.robot.addToolState(0)  # отпустить
    self.robot.addMoveToPointL([Waypoint([dst_pos[0], dst_pos[1], dst_pos[2]+up, rx,ry,rz])])
    self.robot.activateMoveToStart()

def _choose_slot(self, cat):
    for i in self.allowed.get(cat, []):
        if not self.occupied[i]:
            self.occupied[i] = True
            return i
    return None

def run_session(self):
    if not self.session:
        QtWidgets.QMessageBox.warning(self,"Error","List is clear")
        return
    self.add_log("Start move queue")
    try:
        for cat in self.session:
            if cat == 'Reject':
                self._pick_and_place(self.rejectCell, self.rejectTrack)
            else:
                slot = self._choose_slot(cat)
                if slot is None:
                    self.add_log(f"There are no free cells for {cat}, pass")
                    continue
                self._pick_and_place(self.cells[slot], self.cellTrack[slot])
            self.robot.play()
            while self.robot.getActualStateOut() != InterpreterStates.PROGRAM_IS_DONE.value:
                time.sleep(0.1)
        self.add_log("Queue complete")
    except Exception as e:
        self.add_log(f"Error queue: {e}")
        QtWidgets.QMessageBox.warning(self,"Error",str(e))

def closeEvent(self, event):
    self.robot.disengage()
    self.lamp.setLamp("0001")
    print("Close event")
    event.accept()

def main():
    app = QtWidgets.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

[jsulm]

@Borbixxx What does your post have to do with this topic?
"But my code is not running as expected" - is not a problem description.

closeEvent needs to be a method in a class derived from QWidget based class.