from PyQt5 import QtWidgets from MainForm import Ui_MainForm from Children import Ui_Form  from PyQt5.QtWidgets import QFileDialog  class MainForm(QtWidgets.QMainWindow,Ui_MainForm):   def __init__(self):     super(MainForm,self).__init__()     self.setupUi(self)      self.child=ChildrenForm()             #self.child = children()生成子窗口實例self.child       self.fileOpen.triggered.connect(self.openMsg)   #菜單的點擊事件是triggered     self.fileClose.triggered.connect(self.close)     self.actionTst.triggered.connect(self.childShow)  #點擊actionTst,子窗口就會顯示在主窗口的MaingridLayout中    def childShow(self):     self.MaingridLayout.addWidget(self.child)     #添加子窗口     self.child.show()     def openMsg(self):     file,ok=QFileDialog.getOpenFileName(self,"打開","C:/","All Files (*);;Text Files (*.txt)")     self.statusbar.showMessage(file)          #在狀態欄顯示文件地址  class ChildrenForm(QtWidgets.QWidget,Ui_Form):   def __init__(self):     super(ChildrenForm,self).__init__()     self.setupUi(self)  if __name__=="__main__":   import sys    app=QtWidgets.QApplication(sys.argv)   myshow=MainForm()   myshow.show()   sys.exit(app.exec_())