from PyQt5.QtCore import QThread , pyqtSignal, QDateTime , QObject
from PyQt5.QtWidgets import QApplication, QDialog, QLineEdit
import time
import sys

class BackendThread(QObject):
  # 通过类成员对象定义信号
  update_date = pyqtSignal(str)
  
  # 处理业务逻辑
  def run(self):
    while True:
      data = QDateTime.currentDateTime()
      currTime = data.toString("yyyy-MM-dd hh:mm:ss")
      self.update_date.emit( str(currTime) )
      time.sleep(1)

class Window(QDialog):
  def __init__(self):
    QDialog.__init__(self)
    self.setWindowTitle('PyQt 5界面实时更新例子')
    self.resize(400, 100)
    self.input = QLineEdit(self)
    self.input.resize(400, 100)
    self.initUI()

  def initUI(self):
    # 创建线程
    self.backend = BackendThread()
    # 连接信号
    self.backend.update_date.connect(self.handleDisplay)
    self.thread = QThread()
    self.backend.moveToThread(self.thread)
    # 开始线程
    self.thread.started.connect(self.backend.run)
    self.thread.start()

  # 将当前时间输出到文本框
  def handleDisplay(self, data):
    self.input.setText(data)

if __name__ == '__main__':
  app = QApplication(sys.argv)
  win = Window()
  win.show() 
  sys.exit(app.exec_())