Python tkinter label 更新

网上看的两个例子关于tkinter界面更新的，简单易懂，分享一下。

• 例子_1:

• 代码_1:

from tkinter import Tk, Checkbutton, Labelfrom tkinter import StringVar, IntVarroot = Tk()text = StringVar()text.set('old')status = IntVar()def change():    if status.get() == 1:   # if clicked        text.set('new')    else:        text.set('old')cb = Checkbutton(root, variable=status, command=change)lb = Label(root, textvariable=text)cb.pack()lb.pack()root.mainloop()

• 例子_2:

• 代码_2:

from tkinter import *import timeclass StopWatch(Frame):    '''实现一个秒表部件'''    msec = 50    def __init__(self, parent=None, **kw):        Frame.__init__(self, parent, kw)        self._start = 0.0        self._elapsedtime = 0.0        self._running = False        self.timestr = StringVar()        self.makeWidgets()        self.flag  = True    def makeWidgets(self):        '''制作时间标签'''        l = Label(self, textvariable = self.timestr)        self._setTime(self._elapsedtime)        l.pack(fill = X, expand = NO, pady = 2, padx = 2)    def _update(self):        self._elapsedtime = time.time() - self._start        self._setTime(self._elapsedtime)        self._timer = self.after(self.msec, self._update)    def _setTime(self, elap):        '''将时间格式改为 分：秒：百分秒'''        minutes = int(elap/60)        seconds = int(elap-minutes*60.0)        hseconds = int((elap - minutes*60.0 - seconds) *100)        self.timestr.set('%2d:%2d:%2d' %(minutes, seconds, hseconds))    def Start(self):        if not self._running:            self._start = time.time() - self._elapsedtime            self._update()            self._running = True    def Stop(self):        '''停止秒表'''        if self._running:            self.after_cancel(self._timer)            self._elapsedtime = time.time() - self._start            self._setTime(self._elapsedtime)            self._running = False    def Reset(self):        '''重设秒表'''        self._start = time.time()        self._elapsedtime = 0.0        self._setTime(self._elapsedtime)    def stopwatch(self):        if self.flag == True:            self.pack(side = TOP)            Button(self, text = 'start', command = self.Start).pack(side = LEFT)            Button(self, text = 'stop', command = self.Stop).pack(side = LEFT)            Button(self, text = 'reset', command = self.Reset).pack(side = LEFT)            Button(self, text = 'quit', command = self.quit).pack(side = LEFT)             self.flag = Falseclass Watch(Frame):    msec = 1000    def __init__(self, parent=None, **kw):            Frame.__init__(self, parent, kw)            self._running = False            self.timestr1 = StringVar()            self.timestr2 = StringVar()            self.makeWidgets()            self.flag  = True    def makeWidgets(self):        l1 = Label(self, textvariable = self.timestr1)        l2 = Label(self, textvariable = self.timestr2)        l1.pack()        l2.pack()    def _update(self):        self._settime()        self.timer = self.after(self.msec, self._update)    def _settime(self):        today1 = str(time.strftime('%Y-%m-%d', time.localtime(time.time())))        time1 = str(time.strftime('%H:%M:%S', time.localtime(time.time())))        self.timestr1.set(today1)        self.timestr2.set(time1)    def start(self):        self._update()        self.pack(side = TOP)if __name__ == '__main__':    def main():        root = Tk()        root.geometry('250x150')        frame1 = Frame(root)        frame1.pack(side = BOTTOM)        sw = StopWatch(root)        stpwtch = Button(frame1, text = '秒表', command = sw.stopwatch)        stpwtch.pack(side = RIGHT)        mw = Watch(root)        mywatch = Button(frame1, text = '时钟', command = mw.start)        mywatch.pack(side = LEFT)        root.mainloop()    main()