我无法找到一种干净的方法来修改代码来执行您想要的操作，因此决定将秒表实现为一个类，以使程序更加面向对象并避免使用一堆全局变量。
I haven't tested this thoroughly, but there's enough of it working to give you the idea. Note also that I changed a Resume button into one that toggles itself between that and being Pause button. This approach made adding a third one unnecessary.
Update
我注意到可能存在潜在问题，因为越来越多的对象不断添加到Canvas当显示更新时。对于短期运行来说这不应该是问题StopWatch实例，但可能会导致长期运行的问题。
为了避免这种情况，我修改了代码来更新现有的对应Canvas文本对象（如果有）。我也搬了Buttons 到顶部，在StopWatch.
from functools import partial
import time
import tkinter as tk
PAUSE, RESUME = 0, 1 # Button states.
# Button callback functions.
def _toggle(callback):
toggle_btn.state = 1 - toggle_btn.state # Toggle button state value.
toggle_btn.config(**toggle_btn_states[toggle_btn.state])
callback()
def _stop():
stopwatch.cancel_updates()
toggle_btn.config(state=tk.DISABLED)
stop_btn.config(state=tk.DISABLED)
class StopWatch:
def __init__(self, parent, run_time, width, height):
self.run_time = run_time
self.width, self.height = width, height
self.font = 'Arial 600'
self.canvas = tk.Canvas(parent, width=width, height=height, bg='white')
self.canvas.pack()
self.canvas.create_text(950, 300, text=':', font=self.font)
self.running, self.paused = False, False
self.after_id = None
def start(self):
self.elapsed_time = 0 # In seconds.
self._display_time()
self.after_id = self.canvas.after(1000, self._update)
self.running, self.paused = True, False
def _update(self):
if self.running and not self.paused:
if self.elapsed_time == self.run_time:
_stop() # Sets self.running to False.
self.canvas.bell() # Beep.
else:
self.elapsed_time += 1
self._display_time()
if self.running: # Keep update process going.
self.after_id = self.canvas.after(1000, self._update)
def _display_time(self):
mins, secs = divmod(self.elapsed_time, 60)
self._write_seconds(secs)
self._write_minutes(mins)
def _write_minutes(self, mins):
self._write(0, 900, 450, 'mins', mins)
def _write_seconds(self, secs):
self._write(1000, 1900, 1450, 'secs', secs)
def _write(self, x_rec, y_rec, x_text, tag, value):
text = '%02d' % value
# Update canvas text widget if it has non-empty text.
if self.canvas.itemcget(tag, 'text'):
self.canvas.itemconfigure(tag, text=text)
else: # Otherwise create it.
self.canvas.create_text(x_text, 400, text=text, tag=tag, font=self.font)
def pause_updates(self):
if self.running:
self.paused = True
def resume_updates(self):
if self.paused:
self.paused = False
def cancel_updates(self):
self.running, self.paused = False, False
if self.after_id:
self.canvas.after_cancel(self.after_id)
self.after_id = None
# main
root = tk.Tk()
# Create a Frame for Buttons (allows row of them to be centered).
button_frame = tk.Frame(root)
button_frame.pack(side=tk.TOP)
# Create StopWatch and configure buttons to use it.
stopwatch = StopWatch(root, 5, 1900, 1000)
toggle_btn = tk.Button(button_frame)
toggle_btn_states = {}
# Dictionary mapping state to button configuration.
toggle_btn_states.update({
PAUSE: dict(
text='Pause', bg='red', fg='white',
command=partial(_toggle, stopwatch.pause_updates)),
RESUME: dict(
text='Resume', bg='green', fg='white',
command=partial(_toggle, stopwatch.resume_updates))
})
toggle_btn.state = PAUSE
toggle_btn.config(**toggle_btn_states[toggle_btn.state])
toggle_btn.pack(side=tk.LEFT, padx=2)
stop_btn = tk.Button(button_frame, text='Stop', bg='blue', fg='white', command=_stop)
stop_btn.pack(side=tk.LEFT, padx=2)
stopwatch.start()
root.mainloop()
这是显示秒表运行的屏幕截图：
