问题
I want to create a timer in python with the following functions:
timer.start() - should start the timer
timer.pause() - should pause the timer
timer.resume() - should resume the timer
timer.get() - should return the current time
The timer should run from 0 upwards. It is meant to measure time, not trigger a callback function.
So if you start it, it should start counting the seconds like 0 1 2 3, if you pause it, it should be stilll at 3, but not going further. After its resumed it then goes on with 4 5 6 and so on
How can I do this?
Pause/Resume functions for timer is not a duplicate because I do not care about callbacks.
回答1:
# mytimer.py
from datetime import datetime
import time
class MyTimer():
"""
timer.start() - should start the timer
timer.pause() - should pause the timer
timer.resume() - should resume the timer
timer.get() - should return the current time
"""
def __init__(self):
print('Initializing timer')
self.timestarted = None
self.timepaused = None
self.paused = False
def start(self):
""" Starts an internal timer by recording the current time """
print("Starting timer")
self.timestarted = datetime.now()
def pause(self):
""" Pauses the timer """
if self.timestarted is None:
raise ValueError("Timer not started")
if self.paused:
raise ValueError("Timer is already paused")
print('Pausing timer')
self.timepaused = datetime.now()
self.paused = True
def resume(self):
""" Resumes the timer by adding the pause time to the start time """
if self.timestarted is None:
raise ValueError("Timer not started")
if not self.paused:
raise ValueError("Timer is not paused")
print('Resuming timer')
pausetime = datetime.now() - self.timepaused
self.timestarted = self.timestarted + pausetime
self.paused = False
def get(self):
""" Returns a timedelta object showing the amount of time
elapsed since the start time, less any pauses """
print('Get timer value')
if self.timestarted is None:
raise ValueError("Timer not started")
if self.paused:
return self.timepaused - self.timestarted
else:
return datetime.now() - self.timestarted
if __name__ == "__main__":
t = MyTimer()
t.start()
print('Waiting 2 seconds'); time.sleep(2)
print(t.get())
print('Waiting 1 second'); time.sleep(1)
t.pause()
print('Waiting 2 seconds [paused]'); time.sleep(2)
print(t.get())
print('Waiting 1 second [paused]'); time.sleep(1)
print(t.get())
print('Waiting 1 second [paused]'); time.sleep(1)
t.resume()
print('Waiting 1 second'); time.sleep(1)
print(t.get())
Run
python mytimer.py
Output
Initializing timer Starting timer Waiting 2 seconds Get timer value 0:00:02.001523 Waiting 1 second Pausing timer Waiting 2 seconds [paused] Get timer value 0:00:03.004724 Waiting 1 second [paused] Get timer value 0:00:03.004724 Waiting 1 second [paused] Resuming timer Waiting 1 second Get timer value 0:00:04.008578
回答2:
You can try this code
from tkinter import *
class TimerTest():
def __init__(self, root):
self.root=root
self.is_running=False ## timer is or is not running
self.count=IntVar()
self.max_seconds=60
Label(root, textvariable=self.count, font=('DejaVuSansMono', 12, "bold"),
bg="lightyellow").grid(row=1, column=0, columnspan=2, sticky="ew")
Button(root, text="Start", fg="blue", width=15,
command=self.startit).grid(row=10, column=0, sticky="nsew")
Button(root, text="Stop", fg="red", width=15,
command=self.stopit).grid(row=10, column=1, sticky="nsew")
Button(self.root, text="Quit", bg="orange",
command=self.root.quit).grid(row=11, column=0,
columnspan=2, sticky="nsew")
def startit(self):
if not self.is_running: ## avoid 2 button pushes
self.is_running=True
self.increment_counter()
def increment_counter(self):
if self.is_running:
c=self.count.get() +1
self.count.set(c)
if c < self.max_seconds: ## time is not up
self.root.after(1000, self.increment_counter) ## every second
else: ## time is up so exit
self.is_running=False
Label(root, text="Time Is Up", font=('DejaVuSansMono', 14, "bold"),
bg="red").grid(row=5, column=0, columnspan=2, sticky="ew")
def stopit(self):
self.is_running = False
root = Tk()
TT=TimerTest(root)
root.mainloop()
来源：https://stackoverflow.com/questions/60026296/how-to-make-a-pausable-timer-in-python