```
from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtWidgets import *
import sys
class Ui_MainWindow(object): # 这个类是 qt designber 生成的
def setupUi(self, MainWindow):
if not MainWindow.objectName():
MainWindow.setObjectName(u"MainWindow")
MainWindow.resize(302, 252)
self.actionsave = QAction(MainWindow)
self.actionsave.setObjectName(u"actionsave")
self.action = QAction(MainWindow)
self.action.setObjectName(u"action")
self.centralwidget = QWidget(MainWindow)
self.centralwidget.setObjectName(u"centralwidget")
self.verticalLayout_2 = QVBoxLayout(self.centralwidget)
self.verticalLayout_2.setObjectName(u"verticalLayout_2")
self.verticalLayout = QVBoxLayout()
self.verticalLayout.setObjectName(u"verticalLayout")
self.label = QLabel(self.centralwidget)
self.label.setObjectName(u"label")
self.verticalLayout.addWidget(self.label)
self.lineEdit = QLineEdit(self.centralwidget)
self.lineEdit.setObjectName(u"lineEdit")
self.verticalLayout.addWidget(self.lineEdit)
self.pushButton = QPushButton(self.centralwidget)
self.pushButton.setObjectName(u"pushButton")
self.verticalLayout.addWidget(self.pushButton)
self.label_2 = QLabel(self.centralwidget)
self.label_2.setObjectName(u"label_2")
self.verticalLayout.addWidget(self.label_2)
self.lineEdit_2 = QLineEdit(self.centralwidget)
self.lineEdit_2.setObjectName(u"lineEdit_2")
self.verticalLayout.addWidget(self.lineEdit_2)
self.verticalLayout_2.addLayout(self.verticalLayout)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QMenuBar(MainWindow)
self.menubar.setObjectName(u"menubar")
self.menubar.setGeometry(QRect(0, 0, 302, 23))
self.menu = QMenu(self.menubar)
self.menu.setObjectName(u"menu")
self.menu_2 = QMenu(self.menubar)
self.menu_2.setObjectName(u"menu_2")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QStatusBar(MainWindow)
self.statusbar.setObjectName(u"statusbar")
MainWindow.setStatusBar(self.statusbar)
self.menubar.addAction(self.menu.menuAction())
self.menubar.addAction(self.menu_2.menuAction())
self.menu.addAction(self.actionsave)
self.menu.addAction(self.action)
self.retranslateUi(MainWindow)
QMetaObject.connectSlotsByName(MainWindow)
# setupUi
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(QCoreApplication.translate("MainWindow", u"\u6c47\u7387\u6362\u7b97\u5668", None))
self.actionsave.setText(QCoreApplication.translate("MainWindow", u"save", None))
self.action.setText(QCoreApplication.translate("MainWindow", u"\u4fdd\u5b58", None))
self.label.setText(QCoreApplication.translate("MainWindow", u"USD", None))
self.pushButton.setText(QCoreApplication.translate("MainWindow", u"\u8f6c\u6362", None))
self.label_2.setText(QCoreApplication.translate("MainWindow", u"RMB", None))
self.menu.setTitle(QCoreApplication.translate("MainWindow", u"\u83dc\u5355", None))
self.menu_2.setTitle(QCoreApplication.translate("MainWindow", u"\u5e2e\u52a9", None))
# retranslateUi
def click_success():
print("well done log")
app = QApplication(sys.argv)
MainWindow = QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
ui.pushButton.clicked.connect(click_success) # 这是单线程的情况
# 在不是多线程的时候,是它在运行
# 如果 convert 函数中的运算量很大，就会卡死
sys.exit(app.exec_())
```