PyQt5，ui转py的时候需要改一下代码

头部加

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.Qt import *
class MyWindow(QtWidgets.QMainWindow):
    my_button = pyqtSignal()
    def __init__(self,parent=None,*args,**kwargs):
        super(MyWindow,self).__init__(parent,*args,**kwargs)
        self.setupUi(self)

尾部加

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    mywindow = MyWindow()
    mywindow.show()
    sys.exit(app.exec_())

槽函数改：把Form改成self

self.pushButton.clicked.connect(self.my_def)

信号是：

my_button = pyqtSignal()

内部槽函数写

 self.my_button.emit()

整体：

# -*- coding: utf-8 -*-
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.Qt import *
class MyWindow(QtWidgets.QMainWindow):
    my_button = pyqtSignal()
    def __init__(self,parent=None,*args,**kwargs):
        super(MyWindow,self).__init__(parent,*args,**kwargs)
        self.setupUi(self)
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(400, 300)
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(150, 120, 101, 41))
        self.pushButton.setObjectName("pushButton")
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(140, 40, 191, 41))
        self.label.setObjectName("label")
        self.retranslateUi(Form)
        self.pushButton.clicked.connect(self.my_def)
        QtCore.QMetaObject.connectSlotsByName(Form)
    def my_def(self):
        self.my_button.emit()
    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "切换"))
        self.label.setText(_translate("Form", "我是第一个界面"))

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    mywindow = MyWindow()
    mywindow.show()
    sys.exit(app.exec_())

外部就是：

# *_*coding:utf-8 *_*
# @Author : zyb
import one
from PyQt5.Qt import *
if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = one.MyWindow()
    def my_def_w():
        print(999)
    window.my_button.connect(my_def_w)
    window.show()
    sys.exit(app.exec_())