我有一个名为“第一页”的QmainWindow，其中有两个按钮“登录”和“注册”。两个按钮都将打开Qdialog。在登录对话框中，我进行了两行编辑，分别接受用户的输入和两个按钮“取消”和“确定”。单击“确定”后，我要检查一些验证，例如，如果行编辑为空，则在对话框顶部显示QmessageBox，然后在用户单击消息框上的“确定”后关闭消息框。

我的问题：打开消息框后，对话框关闭。 附注：我一直在通过修改我刚刚发现的QtDesigner代码来实现我的代码，这是最糟糕的事情！所以我再做一遍。那时我没有这个问题。

我的代码：

import sys
from PyQt5 import QtWidgets as qtw 
from PyQt5 import QtCore as qtc 
from PyQt5 import QtGui as qtg 
from first_page import Ui_first_page
from signin_page import Ui_signin_page
from signup_page import Ui_signup_page

class SignIn(qtw.QDialog):

    def __init__(self,*args,**kwargs):
        """SignIn constructor."""
        super().__init__(*args,**kwargs)
        self.ui = Ui_signin_page()
        self.ui.setupUi(self)

        # Connects the function that inputs data for sign in to the OK button.
        self.ui.signin_buttons.accepted.connect(self.sign_in_authenticate)

    def sign_in_authenticate(self):
        """Inputs the user's username and password for sign in process and checks validations"""
        input_username = self.ui.signin_username_lineEdit.text()
        input_password = self.ui.signin_password_lineEdit.text()

        # Check if both are filled
        if input_username == "":
            #MY PROBLEM IS HERE
            qtw.QMessageBox.critical(self,"Note","Please input your username.")

        elif input_password == "":
            qtw.QMessageBox.critical(self,"Please input your password.")

        else: 
            # Checks validations and opens mainpage
            open_main_page(self,username,status)

    def open_main_page(self,status):
        """ Opens the main page after sign in"""
        pass

class FirstPage(qtw.QMainWindow):
    def __init__(self,**kwargs):
        """FirstPage constructor."""
        super().__init__(*args,**kwargs)

        self.ui = Ui_first_page()
        self.ui.setupUi(self)

        # Connecting the buttons to open Sign in and Sign out pages
        self.ui.first_page_sign_in_button.clicked.connect(self.open_sign_in_page)
        self.ui.first_page_sign_up_button.clicked.connect(self.open_sign_up_page)

        self.show()

    def open_sign_in_page(self):
        self.sigin = SignIn()
        self.sigin.show()

    def open_sign_up_page(self):
        self.signup = SignUp()
        self.signup.show()


class SignUp(qtw.QDialog):
#Doesn't do anything yet.
    def __init__(self,**kwargs):
        super().__init__(*args,**kwargs)
        self.ui = Ui_signup_page()
        self.ui.setupUi(self)

    
if __name__ == '__main__':
    app = qtw.QApplication(sys.argv)
    window = FirstPage()
    sys.exit(app.exec_())

我很新，所以如果我做任何非常错误的事情，请指出。 预先感谢。

我的问题的迷你示例：

主要代码：

import sys
from PyQt5 import QtWidgets as qtw 
from PyQt5 import QtCore as qtc 
from PyQt5 import QtGui as qtg 
from mainwindow import Ui_MainWindow
from dialog import Ui_signin_Dialog

class SignIn(qtw.QDialog):

    def __init__(self,**kwargs)
        self.ui = Ui_signin_Dialog()
        self.ui.setupUi(self)

        # Connects the function that inputs data for sign in to the OK button.
        self.ui.signin_buttonBox.accepted.connect(self.sign_in_authenticate)

    def sign_in_authenticate(self):
        input_text = self.ui.input_lineEdit.text()

        if input_text == "":
            qtw.QMessageBox.critical(self,"Please input your data.")


class FirstPage(qtw.QMainWindow):
    def __init__(self,**kwargs)

        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        # Connecting the buttons to open Sign in and Sign out pages
        self.ui.signin_pushButton.clicked.connect(self.open_sign_in_page)

        self.show()

    def open_sign_in_page(self):
        self.sigin = SignIn()
        self.sigin.show()

if __name__ == '__main__':
    app = qtw.QApplication(sys.argv)
    window = FirstPage()
    sys.exit(app.exec_())

Ui_MainWindow：

class Ui_MainWindow(object):
    def setupUi(self,MainWindow):
        MainWindow.setobjectname("MainWindow")
        MainWindow.resize(311,293)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setobjectname("centralwidget")
        self.signin_pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.signin_pushButton.setGeometry(QtCore.QRect(100,110,89,25))
        self.signin_pushButton.setobjectname("signin_pushButton")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0,311,22))
        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)

    def retranslateUi(self,MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow","MainWindow"))
        self.signin_pushButton.setText(_translate("MainWindow","Sign in "))

Ui_signin_Dialog

class Ui_signin_Dialog(object):
    def setupUi(self,signin_Dialog):
        signin_Dialog.setobjectname("signin_Dialog")
        signin_Dialog.resize(400,300)
        self.signin_buttonBox = QtWidgets.QDialogButtonBox(signin_Dialog)
        self.signin_buttonBox.setGeometry(QtCore.QRect(290,230,80,56))
        self.signin_buttonBox.setOrientation(QtCore.Qt.Vertical)
        self.signin_buttonBox.setStandardButtons(QtWidgets.QDialogButtonBox.Cancel|QtWidgets.QDialogButtonBox.Ok)
        self.signin_buttonBox.setobjectname("signin_buttonBox")
        self.input_lineEdit = QtWidgets.QLineEdit(signin_Dialog)
        self.input_lineEdit.setGeometry(QtCore.QRect(140,130,113,25))
        self.input_lineEdit.setobjectname("input_lineEdit")

        self.retranslateUi(signin_Dialog)
        self.signin_buttonBox.accepted.connect(signin_Dialog.accept)
        self.signin_buttonBox.rejected.connect(signin_Dialog.reject)
        QtCore.QMetaObject.connectSlotsByName(signin_Dialog)

    def retranslateUi(self,signin_Dialog):
        _translate = QtCore.QCoreApplication.translate
        signin_Dialog.setWindowTitle(_translate("signin_Dialog","Dialog"))

我希望Qmessagebox像弹出消息一样打开，而不是关闭对话框。