timecount.py

from PySide.QtGui import *
from PySide.QtCore import QTimer
app = QApplication([])
widget = QWidget()
textbox = QLineEdit()
startbutton = QPushButton("start/stop")
resetbutton = QPushButton("reset")
timelabel = QLabel("00:00:00")
counttimer = QTimer()
hboxlayout = QHBoxLayout()
vboxlayout = QVBoxLayout()
hboxlayout.addWidget(textbox)
vboxlayout.addWidget(startbutton)
vboxlayout.addWidget(resetbutton)
hboxlayout.addLayout(vboxlayout)
hboxlayout.addWidget(timelabel)
widget.setLayout(hboxlayout)
timecnt = 0
def updatewidget():
    global widget, textbox, timecnt, timelabel
    timecnt += 1
    timelabel.setText(u"%02d:%02d:%02d"%(timecnt/3600, timecnt%3600/60, timecnt%60))

counttimer.timeout.connect(updatewidget)

state = 1
def startclicked():
    global counttimer, state
    if state==1:
        counttimer.start(1000)
        state = 0
    else:
        counttimer.stop()
        state = 1

startbutton.clicked.connect(startclicked)

def resetclicked():
    global timelabel, timecnt
    timelabel.setText("00:00:00")
    timecnt = 0

resetbutton.clicked.connect(resetclicked)

widget.show()
app.exec_()