如何使用RPi按钮在任何时候中断GPIO TKinter循环
如何使用RPi按钮在任何时候中断GPIO TKinter循环
提问于 2017-01-15 16:09:35
这是第二个版本的一个程序，我正在挣扎。我早些时候发布了一个关于这个程序的第一个版本的问题，但是没有运气。
这是我的“大图片的想法”，如果它能帮助你找到我偏离轨道的地方。我有很多植物需要浇水，我想用TKinter制作一个图形用户界面，它将出现在Raspberry Pi上的触摸屏上。Pi控制连接到水泵上的110 V继电器开关。它只是基本的“开/关”循环的z#的植物。
用户有三个滑块来调整，X，Y和Z值。X是水泵需要开多久，Y是水泵需要关闭多长时间(所以你有时间把水管实际移到下一个工厂)，Z是你需要浇水的植物总数。我过去总是让循环永远运行，因为我总是可以让CTRL-C程序结束，但现在我试图让它在触摸屏上实现，而不需要键盘--比教一个不懂Linux意味着如何使用终端的人更方便用户。它还需要像人们习惯看到的程序那样运行，因此GUI触摸屏按钮(比如智能手机和平板电脑)。
大多数情况下，代码运行良好，它停止并开始时没有崩溃。我计算出了开始按钮，并且有一个重置按钮来清除滑块值，以防您想要在零处重新启动这些值。但最大的问题，似乎影响了这里的许多人，是该死的退出按钮。
我需要用户能够在循环期间的任何时间按下TKinter退出按钮，并让程序知道何时按下按钮并立即服从它，基本上是中断了循环。我试过很多事，什么都没用。复选按钮只会等到循环结束，然后更新切换值。此时为时已晚，我需要用户在整个浇水循环中进行控制。
我也不希望程序退出时退出，相反，我希望GPIO循环在"OFF“值上停止，并基本上将程序重置为开始状态。
我知道time.sleep()很粗糙，但我没有找到其他的方法。我见过人们谈论“线程”，我不知道这意味着什么，听起来我永远也不会。我还看到人们谈论过TKinters的"after()“函数，同样，我需要非常清楚的例子来回答。只是说“使用线程”没有任何帮助-我是个菜鸟！
from tkinter import *
import RPi.GPIO as GPIO
import time
master = Tk()
def onoffcycle():
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(14, GPIO.OUT)
GPIO.setup(14, GPIO.LOW)
y=off.get()
y=float(y)
x=on.get()
x=float(x)
GPIO.output(14, True)
print("On")+str(x)
time.sleep(x)
GPIO.output(14, False)
print("Off")+str(y)
time.sleep(y)
def start():
print("Prepare to water in 10 seconds...")
time.sleep(10)
z=cycle.get()
z=float(z)
while z > 0:
onoffcycle()
z=z-1
print("Cycles remaining:")+str(z)
###tog()
###if t==1:
###reset()
else:
reset()
### this program runs onoffcycle() for z number of cycles as set by the slider.
### It should check for an exit toggle, then run the program for one cycle,
### then check for exit, then another round. countdown from cycle.get variable
def reset():
GPIO.cleanup()
on.set(0)
off.set(0)
cycle.set(0)
t=IntVar()
###def tog():
### HELP! This is where I need the program to be looking for the EXIT button being pressed
### in order to stop the program. Everything I have tried so far waits until the z value drops
### to zero, basically until the program stops on its own. I need a button that interrupts
### everything.
on = Scale(master, label="Set # Seconds Water ON:", from_=0, to=180, orient=HORIZONTAL, length=400, width=35,
troughcolor="red", bg="SteelBlue1", fg="black", bd=6, sliderlength=90, sliderrelief=RIDGE,
font = '-weight bold')
on.grid(column=1, row=1, columnspan=3)
off = Scale(master, label="Set # Seconds Water OFF:", from_=0, to=30, orient=HORIZONTAL, length=400, width=35,
troughcolor="yellow", bg="SteelBlue1", fg="black", bd=6, sliderlength=90, sliderrelief=RIDGE,
font = '-weight bold')
off.grid(column=1, row=2, columnspan=3)
cycle = Scale(master, label="Set # of Plants to Water:", from_=0, to=200, orient=HORIZONTAL, length=400, width=35,
troughcolor="green", bg="SteelBlue1", fg="black", bd=6, sliderlength=90, sliderrelief=RIDGE,
font = '-weight bold')
cycle.grid(column=1, row=3, columnspan=3)
go = Button(master, text="START", command=start, bg="SteelBlue3", width=10, height=2, font='-weight bold')
go.grid(column=1, row=4)
adios = Checkbutton(master, text="EXIT", variable=t, indicatoron=0, bd=6, bg="SteelBlue3", width=11, height=2, font='-weight bold')
adios.grid(column=3, row=4)
###adios should have a command to run an exit program - with toggle values? or something else?
resetbutton = Button(master, text="RESET", command=reset, bg="SteelBlue3", width=10, height=2, font='-weight bold')
resetbutton.grid(column=2, row=4)
mainloop()回答 2
Stack Overflow用户
回答已采纳
发布于 2017-01-15 17:01:41
使用布尔变量True/False控制循环和其他元素
例如，创建全局变量。
time_to_exit = False当您按下True按钮时，将其设置为EXIT
并在功能上使用
while z > 0 and not time_to_exit:它应该停止循环。
如果循环停止并退出，您可以使用其他布尔变量通知程序。
# inform function to use global variable
global loop_is_working
loop_is_working = True
while z > 0 and not time_to_exit:
# ...
def reset():
# inform function to use global variable
global loop_is_working
loop_is_working = False
def on_exit:
if loop_is_working:
reset()
# check again afte 100ms
after(100, on_exit)
else:
# stop `mainloop()` and close tkinter window
root.destroy()另一个问题是:您使用了sleep()和while，所以Tkinter必须等到它结束。
您可以使用master.after(miliseconds, function_name)和Tkinter/mainloop来执行这个函数，同时它也可以检查按钮。
示例
time_to_exit = False
def start():
print("Prepare to water in 10 seconds...")
# mainloop will run `start_loop` after `10s`
master.after(10000, start_loop) # 10s = 10 000ms
def start_loop():
z = float(cycle.get())
loop(z)
# or
#master.after(0, loop, z)
def loop(z):
if z > 0 and not time_to_exit:
onoffcycle()
z -= 1
print("Cycles remaining:", z)
###tog()
###if t==1:
###reset()
# mainloop will run `loop` again as soon as possible
master.after(0, loop, z)
else:
reset()甚至是
# create global variables
time_to_exit = False
loop_is_working = False
def start():
# inform function to use global variable
global loop_is_working
loop_is_working = True
print("Prepare to water in 10 seconds...")
# mainloop will run `start_loop` after `10s`
master.after(10000, start_loop) # 10s = 10 000ms
def start_loop():
z = float(cycle.get())
loop(z)
# or
#master.after(0, loop, z)
def loop(z):
if z > 0 and not time_to_exit and loop_is_working:
onoffcycle()
z -= 1
print("Cycles remaining:", z)
###tog()
###if t==1:
###reset()
# mainloop will run `loop` again as soon as possible
master.after(0, loop, z)
else:
reset()
def reset():
# inform function to use global variable
global loop_is_working
# ... your code ...
loop_is_working = FalseStack Overflow用户
发布于 2017-01-17 18:20:39
因此，这是新的代码与furas的优秀建议。我还了解了如何使z值随每次迭代而减少。重置按钮现在将在程序完成当前循环后停止，并等待您启动新的循环。这是因为我仍然让time.sleep()处理打开和关闭时间。我试着用after()来解决这个问题，但是它一直导致其他更大的问题。此时，该程序在技术上是完全可用的，所以我不介意它挂在一个循环中；它不会损害现实世界的应用程序！我仍然有其他的问题，值得他们自己的问题，如配置触摸屏，以正确校准，以及程序自动启动后，自动启动LDXE。我计划将所有内容正确地放置在一个class()中。同时，希望能够在if:语句中更改Label小部件文本。谢谢大家！
#!/usr/bin/python
from Tkinter import *
import ttk
import RPi.GPIO as GPIO
import time
master = Tk()
master.title("Obligatory Title")
master.attributes("-fullscreen", True)
time_to_exit = False
loop_is_working = False
def onoffcycle():
global t
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)
GPIO.output(18, GPIO.LOW)
y=float(off.get())
x=float(on.get())
GPIO.output(18, True)
print("On")+str(x)
t.set("Water ON")
t.get()
time.sleep(x)
GPIO.output(18, False)
print("Off")+str(y)
t.set("Water OFF")
time.sleep(y)
def start():
global loop_is_working
global t
loop_is_working = True
print("Prepare to water in 10 seconds...")
t.set("Prepare to water in 10 seconds...")
master.after(10000, loop)
def loop():
z=float(cycle.get())
global loop_is_working
global time_to_exit
global t
t.set("Now Watering...")
if z > 0 and not time_to_exit and loop_is_working:
onoffcycle()
z=z-1
cycle.set(z)
print("Cycles remaining: ")+ str(z)
master.after(0, loop)
else:
reset()
def reset():
global loop_is_working
GPIO.cleanup()
on.set(0)
off.set(0)
cycle.set(0)
t.set("Welcome! Drag the sliders to set values. Tap left or right of the sliders to fine tune values.")
loop_is_working = False
t = StringVar()
t.set("Welcome! Drag the sliders to set values. Tap left or right of the sliders to fine tune values.")
welcome = Label(master, bg="Steelblue3", bd=6, relief=RAISED, width=92,
height=2, textvariable=t)
welcome.grid(column=1, row=1, columnspan=3)
on = Scale(master, label="Set # Seconds Water ON:", from_=0, to=120, orient=HORIZONTAL, length=735,
width=50, troughcolor="steelblue", bg="SteelBlue1", fg="black", bd=6, sliderlength=90,
sliderrelief=RIDGE)
on.grid(column=1, row=2, columnspan=3)
off = Scale(master, label="Set # Seconds Water OFF:", from_=0, to=30, orient=HORIZONTAL, length=735,
width=50,troughcolor="steelblue", bg="SteelBlue1", fg="black", bd=6, sliderlength=90,
sliderrelief=RIDGE)
off.grid(column=1, row=3, columnspan=3)
cycle = Scale(master, label="Set # of Plants to Water:", from_=0, to=200, orient=HORIZONTAL, length=735,
width=50,troughcolor="steelblue", bg="SteelBlue1", fg="black", bd=6, sliderlength=90,
sliderrelief=RIDGE)
cycle.grid(column=1, row=4, columnspan=3)
go = Button(master, text="START", command=start, bg="green3", width=19, height=3,
bd=4, font='-weight bold')
go.grid(column=1, row=5)
adios = Button(master, text="EXIT", command=exit, bg="red3", width=19, height=3,
bd=4, font='-weight bold')
adios.grid(column=3, row=5)
resetb = Button(master, text="RESET", command=reset, bg="yellow3", width=19,
height=3, bd=4, font='-weight bold')
resetb.grid(column=2, row=5)
mainloop()页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/41663223
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