PyQt5 Popup Window

Question

I am trying to build an app using PyQt5 that has a secondary window "popup" when an item in a QListWidget is double clicked.

Here is the code:

import sys
from PyQt5.QtWidgets import QWidget, QListWidget, QListWidgetItem, QLabel, QPushButton, QApplication


class exampleWidget(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        listWidget = QListWidget(self)
        listWidget.itemDoubleClicked.connect(self.buildExamplePopup)

        names = ["Jack", "Chris", "Joey", "Kim", "Duncan"]

        for n in names:
            QListWidgetItem(n, listWidget)

        self.setGeometry(100, 100, 100, 100)
        self.show()

    @staticmethod
    def buildExamplePopup(item):
        name = item.text()
        exPopup = examplePopup(name)
        exPopup.setGeometry(100, 200, 100, 100)
        exPopup.show()


class examplePopup(QWidget):
    def __init__(self, name):
        super().__init__()

        self.name = name

        self.initUI()

    def initUI(self):
        lblName = QLabel(self.name, self)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = exampleWidget()
    sys.exit(app.exec_())

I want a second window to popup when one of the names in the listbox is double clicked, but I can't for the life of me get the examplePopup widget to draw on screen. Thanks in advance for the help.

Answer 1

The popup window doesn't show because you are not keeping a reference to it, and so it gets garbage-collected as soon as buildExamplePopup returns.

You can easily fix the problem like this:

    def buildExamplePopup(self, item):
        name = item.text()
        self.exPopup = examplePopup(name)
        self.exPopup.setGeometry(100, 200, 100, 100)
        self.exPopup.show()

Answer 2

I can't really tell why it's not working with QWidget since it does work if the second widget is initialized inside the __main__. However you can make use of a QDialog to achieve the same result:

import sys

from PyQt5.QtCore import pyqtSlot
from PyQt5.QtWidgets import QWidget, QListWidget, QListWidgetItem, QLabel, QApplication, QDialog


class ExampleWidget(QWidget):

    def __init__(self):
        super().__init__()
        listWidget = QListWidget(self)
        listWidget.itemDoubleClicked.connect(self.buildExamplePopup)
        for n in ["Jack", "Chris", "Joey", "Kim", "Duncan"]:
            QListWidgetItem(n, listWidget)
        self.setGeometry(100, 100, 100, 100)
        self.show()

    @pyqtSlot(QListWidgetItem)
    def buildExamplePopup(self, item):
        exPopup = ExamplePopup(item.text(), self)
        exPopup.setGeometry(100, 200, 100, 100)
        exPopup.show()


class ExamplePopup(QDialog):

    def __init__(self, name, parent=None):
        super().__init__(parent)
        self.name = name
        self.label = QLabel(self.name, self)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    ex = ExampleWidget()
    sys.exit(app.exec_())

I also changed a bit your code adding the @pyqtSlot decorator to the itemDoubleClicked signal slot handler (you should not declare slots as static).