PyQt5 implements download progress bar effect

# -*- coding: utf-8 -*- 
 
from PyQt5 import QtCore, QtGui, QtWidgets 
from PyQt5.Qt import Qt 
 
class Ui_download(object): 
  def setupUi(self, Dialog): 
    Dialog.setWindowFlags(Qt.FramelessWindowHint) 
    Dialog.setObjectName("Dialog") 
    Dialog.resize(300, 56) 
    Dialog.setFixedSize(Dialog.width(), Dialog.height()) 
    sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Fixed, QtWidgets.QSizePolicy.Fixed) 
    sizePolicy.setHorizontalStretch(0) 
    sizePolicy.setVerticalStretch(0) 
    sizePolicy.setHeightForWidth(Dialog.sizePolicy().hasHeightForWidth()) 
    Dialog.setSizePolicy(sizePolicy) 
    Dialog.setSizeGripEnabled(True) 
    self.gridLayout = QtWidgets.QGridLayout(Dialog) 
    self.gridLayout.setSizeConstraint(QtWidgets.QLayout.SetDefaultConstraint) 
    self.gridLayout.setObjectName("gridLayout") 
    self.progressBar = QtWidgets.QProgressBar(Dialog) 
    self.progressBar.setProperty("value", 0) 
    self.progressBar.setAlignment(QtCore.Qt.AlignLeading|QtCore.Qt.AlignLeft|QtCore.Qt.AlignVCenter) 
    self.progressBar.setObjectName("progressBar") 
    self.gridLayout.addWidget(self.progressBar, 1, 0, 1, 1) 
    self.label = QtWidgets.QLabel(Dialog) 
    self.label.setObjectName("label") 
    self.gridLayout.addWidget(self.label, 0, 0, 1, 1) 
 
    self.retranslateUi(Dialog) 
    QtCore.QMetaObject.connectSlotsByName(Dialog) 
 
  def retranslateUi(self, Dialog): 
    _translate = QtCore.QCoreApplication.translate 
    Dialog.setWindowTitle(_translate("Dialog", "Dialog")) 
    self.label.setText(_translate("Dialog", "客户端更新下载中...")) 
 
 
if __name__ == "__main__": 
  import sys 
  app = QtWidgets.QApplication(sys.argv) 
  Dialog = QtWidgets.QDialog() 
  ui = Ui_download() 
  ui.setupUi(Dialog) 
  Dialog.show() 
  sys.exit(app.exec_())

# -*- coding: utf-8 -*- 
 
""" 
Module implementing Dialog. 
""" 
 
from PyQt5.QtCore import QThread, pyqtSignal 
from PyQt5.QtWidgets import QDialog 
from PyQt5 import QtWidgets 
from Ui_download import Ui_download 
import os 
import sys 
import requests 
 
 
class downloadThread(QThread): 
 
  download_proess_signal = pyqtSignal(int) 
 
  def __init__(self, download_url, filesize, fileobj, buffer): 
    super(downloadThread, self).__init__() 
    self.download_url = download_url 
    self.filesize = filesize 
    self.fileobj = fileobj 
    self.buffer = buffer 
 
  def run(self): 
    try: 
      f = requests.get(self.download_url, stream=True) 
      offset = 0 
      for chunk in f.iter_content(chunk_size=self.buffer): 
        if not chunk: 
          break 
        self.fileobj.seek(offset) 
        self.fileobj.write(chunk) 
        offset = offset + len(chunk) 
        proess = offset / int(self.filesize) * 100 
        self.download_proess_signal.emit(int(proess)) 
      self.fileobj.close() 
      self.exit(0) 
    except Exception as e: 
      print(e) 
 
 
class download(QDialog, Ui_download): 
  """ 
  下载类实现 
  """ 
  def __init__(self, download_url, auto_close=True, parent=None): 
    """ 
    Constructor 
     
    @download_url:下载地址 
    @auto_close:下载完成后时候是否需要自动关闭 
    """ 
    super(download, self).__init__(parent) 
    self.setupUi(self) 
    self.progressBar.setValue(0) 
    self.downloadThread = None 
    self.download_url = download_url 
    self.filesize = None 
    self.fileobj = None 
    self.auto_close = auto_close 
    self.download() 
 
  def download(self): 
    self.filesize = requests.get(self.download_url, stream=True).headers['Content-Length'] 
    path = os.path.join("update", os.path.basename(self.download_url)) 
    self.fileobj = open(path, 'wb') 
    self.downloadThread = downloadThread(self.download_url, self.filesize, self.fileobj, buffer=10240) 
    self.downloadThread.download_proess_signal.connect(self.change_progressbar_value) 
    self.downloadThread.start() 
 
  def change_progressbar_value(self, value): 
    self.progressBar.setValue(value) 
    if self.auto_close and value == 100: 
      self.close() 
 
 
if __name__ == '__main__': 
  app = QtWidgets.QApplication(sys.argv) 
  ui = download() 
  ui.show() 
  sys.exit(app.exec_())