如何在视频播放时更新QtGui.QSlider的位置？

Question

我目前正在使用PyQt4开发视频播放器GUI，并使用QtGuid.QSlider来控制视频流的进度。我想知道在播放视频时如何更改滑块的值？

import sys, os
import xml.etree.ElementTree as ET
from xml.dom import minidom
from PyQt4 import QtCore, QtGui, uic
from PyQt4.phonon import Phonon
class vidplayer(QtGui.QWidget):

def __init__(self,url,xml_url,parent = None):
    self.url = url
    super(vidplayer,self).__init__()
    self.initUI()
    self.getElm_from_XML(xml_url);

def printXMLInfo(self):
    itemlist = self.doc.getElementsByTagName('object')
    for item in itemlist:
        print ("frame-span:"+str(item.attributes['framespan'].value)+
        " Event tag: "+ str(item.attributes['name'].value));
    print(len(itemlist))

def getElm_from_XML(self,xml_url):
    self.doc = minidom.parse(xml_url)
    self.clipList = self.doc.getElementsByTagName('object');
    print("Reading XML done...n Have read %s elements.n" %(len(self.clipList)))

def initUI(self):
    ## create widgets
    # phonon video player and media
    self.vp = Phonon.VideoPlayer()
    media = Phonon.MediaSource(self.url)
    # layout components (boxes)
    self.vbox_play = QtGui.QVBoxLayout()
    self.hbox_ctrl_vid = QtGui.QHBoxLayout()
    self.hbox_ctrl_dec = QtGui.QHBoxLayout()
    self.hbox = QtGui.QHBoxLayout()
    self.vbox_control = QtGui.QVBoxLayout()
    # bottons to control
    self.btn_go_prev = QtGui.QPushButton("|<")
    self.btn_go_next = QtGui.QPushButton(">|")
    self.btn_play = QtGui.QPushButton("Play(Pause)")
    self.btn_accept = QtGui.QPushButton("Accept")
    self.btn_reject = QtGui.QPushButton("Reject")
    # slider to interact with videoplayer
    self.sld = QtGui.QSlider(QtCore.Qt.Horizontal,self)
    #self.sld = Phonon.SeekSlider(self)
    ## layout components setup
    self.vbox_control.addStretch(1)
    self.hbox_ctrl_vid.addStretch(1)
    self.hbox_ctrl_dec.addStretch(1)
    self.vbox_play.addStretch(1)
    self.hbox.addStretch(1)
    self.vbox_control.setDirection(QtGui.QBoxLayout.BottomToTop)
    self.vbox_play.setDirection(QtGui.QBoxLayout.BottomToTop)

    ## widgets inits
    self.vp.load(media)
    self.vp.play()
    self.sld.setFocusPolicy(QtCore.Qt.NoFocus)
    self.sld.setRange(1,1000)

    ## widgets assignment
    self.hbox_ctrl_vid.addWidget(self.btn_go_prev)
    self.hbox_ctrl_vid.addWidget(self.btn_play)
    self.hbox_ctrl_vid.addWidget(self.btn_go_next)
    self.hbox_ctrl_dec.addWidget(self.btn_accept)
    self.hbox_ctrl_dec.addWidget(self.btn_reject)
    self.vbox_play.addWidget(self.vp)
    self.vbox_play.addWidget(self.sld)
    self.vbox_control.addLayout(self.hbox_ctrl_dec)
    self.vbox_control.addLayout(self.hbox_ctrl_vid)
    self.hbox.addLayout(self.vbox_play)
    self.hbox.addLayout(self.vbox_control)

    ## main setup and display
    self.setLayout(self.hbox)
    self.setGeometry(300,300,600,400)
    self.setWindowTitle('CCNY_SRI TRECVid iSED UI')
    self.setWindowIcon(QtGui.QIcon('./icon.png'))
    self.show()

    ## connection set up
    self.sld.valueChanged[int].connect(self.sld_changeValue)
    self.vp.finished.connect(self.onReachingFinish)
    self.btn_play.clicked.connect(self.onClicked_play)
    self.btn_go_next.clicked.connect(self.onClicked_nextClip)
    self.btn_go_prev.clicked.connect(self.onClicked_prevClip)

###################### callable functions ##################
def sld_changeValue(self,value):
    totalT = self.vp.totalTime()
    print totalT
    newT = totalT*value/1000
    self.vp.seek(newT)
def onClicked_play(self):
    # BUG: sth wrong with boundary
    if self.vp.isPaused():
        self.vp.play()
        print("resume play")
    elif self.vp.isPlaying():
        self.vp.pause()
        print("pause at",self.sld.value())
    elif self.sld.value()<1000:
        self.vp.play()
def onClicked_nextClip(self):
    print("go next")
def onClicked_prevClip(self):
    print("go prev")
def onClicked_acc(self):
    print("accepted")
def onClicked_rej(self):
    print("rejected")
def onReachingFinish(self):
    self.vp.pause()
    self.vp.stop()

def main():
    app = QtGui.QApplication(sys.argv)
    window = vidplayer(sys.argv[1],sys.argv[2])
    sys.exit(app.exec_())
if __name__ == '__main__':
    main()

Answer 1

在Phonon:Phonon.SeekSlider:中有一个专用类

class MainWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        # creating player resource
        self.player = Player()
        # adding controls
        self.sliders = Sliders(self.player)
class Sliders(QtGui.QWidget):
    def __init__(self, player):
        QtGui.QWidget.__init__(self)
        self.seek_slider = Phonon.SeekSlider(player , self)
class Player(Phonon.MediaObject):
    def __init__(self):
        Phonon.MediaObject.__init__(self)
        self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self)
        self.path = Phonon.createPath(self, self.audioOutput)

此滑块将直接引导播放，其位置将在媒体播放期间更新。但是，由于这是一个缺点，我正在寻找一个变通方法，没有valueChanged信号：-/