python3.x+pyqt5实现主窗口状态栏里（嵌入）显示进度条功能

from PyQt5.QtWidgets import QMainWindow, QProgressBar, QApplication, QLabel
import sys
class SampleBar(QMainWindow):
  """Main Application"""
  def __init__(self, parent = None):
    print('Starting the main Application')
    super(SampleBar, self).__init__(parent)
    self.initUI()
  def initUI(self):
    # Pre Params:
    self.setMinimumSize(800, 600)
    # File Menus & Status Bar:
    self.statusBar().showMessage('准备中...')
    self.progressBar = QProgressBar()
    self.label = QLabel()
    self.label2 = QLabel()
    self.label.setText("正在计算： ")
    self.label2.setText("正在计算： ")
    self.statusBar().addPermanentWidget(self.label)
    self.statusBar().addPermanentWidget(self.label2)
    self.statusBar().addPermanentWidget(self.progressBar)
    # self.statusBar().addWidget(self.progressBar)
    # This is simply to show the bar
    self.progressBar.setGeometry(0, 0, 100, 5)
    self.progressBar.setRange(0, 500) # 设置进度条的范围
    self.progressBar.setValue(100)
if __name__ == '__main__':
  app = QApplication(sys.argv)
  main2 = SampleBar()
  main2.show()
  sys.exit(app.exec_())

from PyQt5.QtWidgets import QMainWindow, QProgressBar, QApplication, QLabel,   QStatusBar, QPushButton
import sys
class SampleBar(QMainWindow):
  """Main Application"""
  def __init__(self, parent = None):
    # print('Starting the main Application')
    super(SampleBar, self).__init__(parent)
    self.initUI()
  def initUI(self):
    # Pre Params:
    self.setMinimumSize(800, 600)
    # File Menus & Status Bar:
    self.statusBar = QStatusBar()
    self.statusBar.setStyleSheet('QStatusBar::item {border: none;}')
    self.setStatusBar(self.statusBar)
    self.statusBar.showMessage('准备')
    self.progressBar = QProgressBar()
    self.pushbutton = QPushButton("点这里")
    self.label = QLabel()
    self.label2 = QLabel()
    self.label.setText("开始计算 ")
    self.label2.setText("正在计算： ")
    # self.statusBar.addWidget(self.label, 0)
    self.statusBar.addPermanentWidget(self.label, stretch=2)
    self.statusBar.addPermanentWidget(self.label2, stretch=0)
    self.statusBar.addPermanentWidget(self.progressBar, stretch=4)
    # self.statusBar().addWidget(self.progressBar)
    # This is simply to show the bar
    # self.progressBar.setGeometry(0, 0, 100, 5)
    self.progressBar.setRange(0, 500) # 设置进度条的范围
    self.progressBar.setValue(20)
if __name__ == '__main__':
  app = QApplication(sys.argv)
  main2 = SampleBar()
  main2.show()
  sys.exit(app.exec_())