# -*- coding: utf-8 -*-
import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class MainWindow(QMainWindow):
  count=0
  def __init__(self, parent=None):
    super(MainWindow, self).__init__(parent)
    self.mdi = QMdiArea()
    self.setCentralWidget(self.mdi)
    # 添加菜单栏
    bar=self.menuBar()
    file=bar.addMenu("File")
    file.addAction("New")
    file.addAction("cascade")
    file.addAction("Tiled")
    file.triggered[QAction].connect(self.windowaction)
    self.setWindowTitle("MDI 示例")
  def windowaction(self, q): 
    # 通过点击不同的按钮实现不同布局的显示方式
    if q.text()=="New":
      MainWindow.count=MainWindow.count+1
      sub=QMdiSubWindow()
      sub.setWidget(QTextEdit())
      sub.setWindowTitle("subwindow"+str(MainWindow.count))
      self.mdi.addSubWindow(sub)
      sub.show()
    if q.text()=="cascade":
      self.mdi.cascadeSubWindows()
    if q.text()=="Tiled":
      self.mdi.tileSubWindows()
if __name__ == '__main__':
  app = QApplication(sys.argv)
  demo = MainWindow()
  demo.show()
  sys.exit(app.exec_())