pyQt5不让进度条卡住

这里我们用一个更新程序做示例， 下载文件的过程中让进度条实时显示下载进度。

如果下载和更新进度条的工作都放在一个线程中，会出现进度条卡顿的情况。

正确的做法是把界面刷新和工作任务交给不同的线程去运行，然后用信号同步。

# _*_  coding: utf-8  _*_
import os
import sys
import subprocess
from PyQt5.QtCore import (QThread, pyqtSignal, QRect)
from PyQt5.QtWidgets import (QApplication, QDesktopWidget, QProgressBar, QWidget, QLabel, QFrame, QPushButton)
from PyQt5.QtGui import (QIcon, QPixmap)
import requests
import zipfile
import json

class dfThread(QThread):
    _signal = pyqtSignal(int, str, str)

    def __init__(self, download_url, filesize, fileobj, buffer):
        super().__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._signal.emit(int(proess), str(offset), str(self.filesize))
            self.fileobj.close()
            self.exit(0)
        except Exception as e:
            print(e)

class zipFile(object):
    def __init__(self, filename, mode='r', basedir=''):
        self.filename = filename
        self.mode = mode
        if self.mode in ('w', 'a'):
            self.zfile = zipfile.ZipFile(filename, self.mode, compression=zipfile.ZIP_DEFLATED)
        else:
            self.zfile = zipfile.ZipFile(filename, self.mode)
        self.basedir = basedir
        if not self.basedir:
            self.basedir = os.path.dirname(filename)

    def close(self):
        self.zfile.close()

    def extract_to(self, path):
        for p in self.zfile.namelist():
            self.extract(p, path)

    def extract(self, filename, path):
        if not filename.endswith('/'):
            f = os.path.join(path, filename)
            dir = os.path.dirname(f)
            if not os.path.exists(dir):
                os.makedirs(dir)
            try:
                open(f, 'wb').write(self.zfile.read(filename))
            except IOError:
                pass

class updateFrm(QWidget):
    def __init__(self):
        super().__init__()
        self.mainfn  = 'QQ'
        #self.fileuri = 'http://a.b.cn/serv/update/%s.zip' % self.mainfn
        self.fileuri = 'https://dldir1.qq.com/qqfile/qq/PCQQ9.1.1/24953/QQ9.1.1.24953.exe'
        #self.servurl = 'http://a.b.cn/serv/version'
        self.baseTitle = 'QQ升级助手'
        self.initUI()

    def initUI(self):
        self.info = QLabel(self)
        self.info.move(65, 28)
        self.info.resize(360, 40)

        map = QLabel(self)
        map.move(30, 25)
        img = QPixmap('res\\info.png')
        map.setPixmap(img)

        self.tips = QLabel(self)
        self.tips.move(420, 55)
        self.tips.resize(30, 10)
        self.tips.hide()

        self.line = QFrame(self)
        self.line.setGeometry(QRect(0, 75, 500, 75))
        self.line.setFrameShape(QFrame.HLine)
        self.line.setFrameShadow(QFrame.Sunken)
        self.line.setObjectName("line")

        self.btnQuit = QPushButton(self)
        self.btnQuit.setText("取消")
        self.btnQuit.setGeometry(380, 120, 100, 30)
        self.btnQuit.clicked.connect(self.cancel)
        self.btnQuit.hide()

        self.btnStart = QPushButton(self)
        self.btnStart.setText('立即更新')
        self.btnStart.setGeometry(380, 120, 100, 30)
        self.btnStart.clicked.connect(self.start)

        self.bar = QProgressBar(self)
        self.bar.setGeometry(0, 110, 530, 2)
        self.bar.setMaximum(100)
        self.bar.hide()

        self.setFixedSize(500, 160)
        self.center()
        self.setWindowTitle(self.baseTitle)
        icon = QIcon()
        icon.addPixmap(QPixmap("res\\6.ico"), QIcon.Normal, QIcon.Off)
        self.setWindowIcon(icon)

        try:
            #res = requests.get(self.servurl)
            #obj = json.loads(res.text)
            obj = {
                'title': '发现新版本',
                'desc' : 'PCQQ 9.1.1 全新改版，给你焕然一新的感觉'
            }
            txt = '%s\n\n%s' % (obj['title'], obj['desc'])
        except Exception as e:
            txt = '未发现新版本\n\n'
            self.btnStart.setDisabled(True)
        self.info.setText(txt)

        self.show()

    def center(self):
        qr = self.frameGeometry()
        cp = QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())

    def cancel(self):
        self.close()

    def start(self):
        self.btnStart.hide()
        self.bar.show()
        self.tips.show()
        self.line.hide()
        self.btnQuit.setEnabled(False)
        self.btnQuit.show()
        self.downloadfile()

    def downloadfile(self):
        self.bar.setValue(0)
        path = '%s.zip' % self.mainfn
        self.filesize = requests.get(self.fileuri, stream=True).headers['Content-Length']
        self.fileobj  = open(path, 'wb')
        self.dfThread = dfThread(self.fileuri, self.filesize, self.fileobj, buffer=10240)
        self.dfThread._signal.connect(self.progressinfo)
        self.dfThread.start()

    def progressinfo(self, per, f_size_dl, f_size):
        self.bar.setValue(per)
        self.tips.setText('%s%%' % str(per))
        self.info.setText('升级过程中请勿退出\n\n正在下载.. %s/%s bytes' % (str(f_size_dl), str(f_size)))
        if per == 100:
            self.info.setText('升级过程中请勿退出\n\n下载完成,正在安装..')
            self.unzip('%s.zip' % self.mainfn)
            self.tips.hide()
            self.info.setText('安装完成\n\n已升级到最新版本')
            self.btnQuit.setText('完成')
            self.btnQuit.setEnabled(True)

    def unzip(self, fname):
        z = zipFile(fname)
        z.extract_to('.')
        z.close()
        os.remove(fname)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    frm = updateFrm()
    #kill = subprocess.call(("taskkill /F /IM %s.exe" % frm.mainfn), shell=True)
    sys.exit(app.exec_())