不多說了，直接上程式碼記錄:

#!/usr/bin/lgy
#-*-coding:utf-8-*-

import urllib2,threading
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from push_progress import *
from time import time

# 暫時沒用到 多執行緒任務下載用到
lock = threading.RLock()

class UpdateWidget(QWidget):
    def __init__(self,parent=None):
        super(UpdateWidget,self).__init__(parent)
        self.url = ""
        self.buffer = 10000
        self.start_size = 0
        self.end_size = 0
        self.fobj=""

        self.progress=QProgressBar()
        self.connect(self,SIGNAL("Getproess(float)"),self.ceshi2)

        self.size_layout=QHBoxLayout()
        self.sizetotal=QLabel()
        self.connect(self,SIGNAL("Getsizetotal(int)"),self.ceshi3) #接收
        self.sizenow=QLabel()
        self.connect(self,SIGNAL("Getsizenow(int)"),self.ceshi4)
        self.size_layout.addWidget(self.sizenow)
        self.size_layout.addWidget(self.sizetotal)
        self.size_layout.addStretch(1)

        self.speedlabel=QLabel()
        self.speedlabel.setText("50 kb/s")
        self.connect(self,SIGNAL("Getspeed(float)"),self.ceshi)
        self.main_layout=QVBoxLayout()
        self.main_layout.addWidget(self.progress)
        self.main_layout.addLayout(self.size_layout)
        self.main_layout.addWidget(self.speedlabel)

        self.setLayout(self.main_layout)
        self.download()
        self.resize(320,160)

    def download(self):
        url='http://down.360safe.com/se/360se7.3.0.146.exe'
        t = threading.Thread(target=self.main,args=(url, 1, 'c:/360.exe',10000))
        t.setDaemon(True)
        t.start()

    def ceshi(self,i):
        speed=round(i,2)
        #判斷Mb，Kb
        if speed>=1000:
            mbspeed=round(speed/1000,2)
            self.speedlabel.setText("{0} Mb/s".format(mbspeed))
        else:
            self.speedlabel.setText("{0} Kb/s".format(speed))


    def ceshi2(self,i):
        self.progress.setValue(round(i,2))
    def ceshi3(self,i):
        stol=round(float(i)/1024/1024,2)
        self.sizetotal.setText("{0} M".format(stol))
    def ceshi4(self,i):
        stol=round(float(i)/1024/1024,2)
        self.sizenow.setText("{0} M / ".format(stol))

    def _download(self,url, totalsize,fobj, buffer):
        start_time=time()
        req = urllib2.Request(url)
        f = urllib2.urlopen(req)
        # 初始化當前檔案位置偏移
        offset = 0
        while 1:
            block = f.read(buffer)
            # 當前執行緒資料獲取完畢後則退出
            if not block:
                print u'完成退出迴圈'
                break

            #當前耗時
            dural_time=float(time()) - float(start_time)
            # 設定檔案物件偏移地址
            fobj.seek(offset)
            # 寫入獲取到的資料
            fobj.write(block)
            offset = offset + len(block)
            #計算下載速度
            speed = (float(offset)/float(dural_time)/(1000*1000))*1000
            #計算下載進度
            proess=float(offset)/float(totalsize)*100
            #print proess
            self.emit(SIGNAL("Getsizenow(int)"),offset) #傳送當前檔案大小訊號
            self.emit(SIGNAL("Getproess(float)"),proess) #傳送當前進度
            self.emit(SIGNAL("Getspeed(float)"),speed)   #傳送當前下載速度

    def main(self,url, thread=1, save_file='', buffer=1024):
        # 獲取檔案的大小
        req = urllib2.urlopen(url)
        size = int(req.info().getheaders('Content-Length')[0])
        self.emit(SIGNAL("Getsizetotal(int)"),size)
        # 初始化檔案物件
        self.fobj = open(save_file, 'wb')
        t = self._download(url, size ,self.fobj, buffer)

        # 關閉檔案物件
        self.fobj.close()
        print u'下載完成！'

if __name__=='__main__':
    import sys
    app=QApplication(sys.argv)
    tree=UpdateWidget()
    tree.show()
    sys.exit(app.exec_())
 

後面的可自行拓展功能，效果如下：

下載360的速度有點快。。。。