Python PyQt5 QMessageBox無法打開

Question

當我按infoButton時，我正在嘗試打開一個消息框。 它運行infoDialogue方法，因為它打印“我在這里”，但它不打開infoBox。 我錯過了什么？

我正在使用python 3.5和PyQt5

謝謝！

這是代碼：

import sys
from PyQt5.QtWidgets import (QApplication, QWidget, QToolTip, QPushButton, QMessageBox)
from PyQt5.QtCore import QCoreApplication
from PyQt5.QtGui import QIcon, QFont

class mainWindow(QWidget):

    def __init__(self, screenWidth, screenHeight, windowWidth=400, windowHeight=400):      
        super().__init__()
        self.screenWidth = screenWidth
        self.screenHeight = screenHeight              
        self.windowWidth = windowWidth
        self.windowHeight = windowHeight
        self.initUI()


    def initUI(self):
        QToolTip.setFont(QFont('SansSerif', 10))
        self.setToolTip('ToolTip Widget')

        exitButton = QPushButton('Exit', self)        
        exitButton.setToolTip("<b>Wish to Exit?</b>")        
        exitButton.resize(exitButton.sizeHint())       
        exitButton.move(100, 100)      
        exitButton.clicked.connect(QCoreApplication.instance().quit)           

        infoButton = QPushButton('Info', self) # Button that calls infoDialogue()
        infoButton.setToolTip('<b>ToolTip</b>')
        infoButton.resize(infoButton.sizeHint())
        infoButton.move(100, 200)
        infoButton.clicked.connect(self.infoDialogue)      

        positionX = (self.screenWidth - self.windowWidth) / 2
        positionY = (self.screenHeight - self.windowHeight) / 2
        self.setGeometry(positionX, positionY, self.windowWidth, self.windowHeight)

        self.setWindowTitle('Window Title')
        #self.setWindowIcon(QIcon('./icon.png'))

        self.show()


    def infoDialogue(self): ## Method to open a message box
        infoBox = QMessageBox() ##Message Box that doesn't run
        print("Im here")
        infoBox.setIcon(QMessageBox.Information)
        infoBox.setText("Informações Adicionais")
        infoBox.setInformativeText("Informative Text")
        infoBox.setWindowTitle("Window Title")
        infoBox.setDetailedText("Detailed Text")
        infoBox.setStandardButtons(QMessageBox.Ok | QMessageBox.Cancel)
        infoBox.setEscapeButton(QMessageBox.Close)       


    def closeEvent(self, event):        
        reply = QMessageBox.question(self, 'Exit', "Are you sure you want to exit?", QMessageBox.Yes | QMessageBox.No, QMessageBox.No)                                      
        if reply == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    screenResolution = app.desktop().screenGeometry()
    screenWidth = screenResolution.width()
    screenHeight = screenResolution.height()
    example = mainWindow(screenWidth, screenHeight)
    sys.exit(app.exec_())

Answer 1

你可能需要一個

infoBox.exec_() 

最后實際執行它

Answer 2

或者不需要_ （下划線），直接exec ：

infoBox.exec()

您需要執行消息框才能顯示它。