从窗口tkinter和python传递值

Question

我试图从运行在python上的tkinter中的一个从窗口传递一个值，但我就是搞不懂。以下是我目前掌握的代码：

#!/usr/bin/env python3

import time
import pigpio
from tkinter import *


GPIO=21
GPIO2=16
GPIO3=20

pi = pigpio.pi()
if not pi.connected:
   exit()
pi.set_mode(GPIO,pigpio.OUTPUT)
pi.set_mode(GPIO2,pigpio.OUTPUT)
gv=int()

def tx_pulses(pi, GPIO, hertz, num, pulse_len=1):
   motSpeed = int((1/(dscale.get()))*2000)
   print(motSpeed)
   pulse_len = motSpeed
   assert num < 65536

   num_low = num % 256
   num_high = num // 256

   wf = []

   wf.append(pigpio.pulse(1<<GPIO, 0, pulse_len))
   wf.append(pigpio.pulse(0, 1<<GPIO, pulse_len))
   pi.wave_add_generic(wf)

   wid = pi.wave_create()

   if wid >= 0:
      pi.wave_chain([255, 0, wid, 255, 1, num_low, num_high])
      while pi.wave_tx_busy():
         time.sleep(0.1)
      pi.wave_delete(wid)



def runMotor():
 motRevs = int(((scale.get())*400)*5.08)
 print(motRevs)
 pi.write(GPIO2,0)
 pi.write(GPIO3,1)
 tx_pulses(pi, GPIO, 1000, motRevs) # 250 pulses @ 1000 Hz
 pi.write(GPIO3,0)
 tx_pulses(pi, GPIO, 1000, motRevs) # 2391 pulses @ 5000 Hz
 pi.write(GPIO2,1)

def setUp():
 speedWin = Toplevel()
 speedWin.geometry('800x600')
 speedWin.title('Stepper Control')
 label = Label(speedWin, text='Inches of Travel')
 label.place(x=350, y=100)
 scale = Scale(speedWin, from_=0.0, to=15.0 ,orient=HORIZONTAL,length=600, resolution=0.1, tickinterval=1)
 scale.place(x=100, y=125)
 dlabel = Label(speedWin, text='Speed')
 dlabel.place(x=370, y=200)
 dscale = Scale(speedWin, from_=1, to=10 ,orient = HORIZONTAL,length = 600, tickinterval=1)
 dscale.place(x=100, y=225)
 button = Button(speedWin, text='Apply Values', command=runMotor, padx = 20, pady = 20)
 button.place(x=350, y=350)
 button3 = Button(speedWin, text='Back To Main Window', command=speedWin.destroy, padx=20, pady=20)
 button3.place(x=500, y=350)
 speedWin.mainloop()

mainWin = Tk()
mainWin.geometry('800x600')
mainWin.title('Main Window')
button2 = Button(mainWin, text='Go To Setup', command=setUp, padx=20, pady=20)
button2.place(x=350, y=350)
mainWin.mainloop()
pi.stop()

当我按下“应用值”按钮时，我得到一个错误，说speedWin没有定义。我找了又找，但找不到答案或一些示例代码。完全是新手，所以请温柔点！在

Answer 1

您应该搜索带有tkinter关于组织tkinter代码的问题。不要认为下面的代码是一个很好的例子，只是一个快速运行代码的例子。在

我在代码中看到的主要问题是，保存创建的小部件的变量是setUp函数的本地变量。您可以使它们成为全局变量，并结合使用global关键字从多个函数访问它们。这有点难看，因为你可能开始增加全局变量的数量，你所需要的一切都变成了一个全局变量

但是您也可以为第二个窗口定义一个类，比如ControlPanel，并将访问器函数作为该类的方法，并将小部件保存在变量成员中。如果函数需要引用ControlPanel小部件，那么可以在类外部的代码中说cp.widget_name是cp = ControlPanel()或ControlPanel类代码内的ControlPanel实例对象，可以通过self.widget_name引用。对于小部件或任何其他变量。在

setUp中的代码被传输到ControlPanel __init__，后者在创建时初始化ControPanel对象。注意，类（方法）中的函数现在在其他函数之前需要一个self参数。在

不要调用mainloop两次，mainloop()之后的代码只会在tkinter终止后运行。在

请尝试以下重新组织的代码：

#!/usr/bin/env python3

import time
import pigpio

from tkinter import *


GPIO=21
GPIO2=16
GPIO3=20

pi = pigpio.pi()
if not pi.connected:
   exit()
pi.set_mode(GPIO,pigpio.OUTPUT)
pi.set_mode(GPIO2,pigpio.OUTPUT)
gv=int()

class ControlPanel(Toplevel):

    def __init__(self, *args, **kwargs):
        super().__init__(args, kwargs)
        self.geometry('800x600')
        self.title('Stepper Control')
        self.label = Label(self, text='Inches of Travel')
        self.label.place(x=350, y=100)
        self.scale = Scale(self, from_=0.0, to=15.0 ,orient=HORIZONTAL,length=600, resolution=0.1, tickinterval=1)
        self.scale.place(x=100, y=125)
        self.dlabel = Label(self, text='Speed')
        self.dlabel.place(x=370, y=200)
        self.dscale = Scale(self, from_=1, to=10 ,orient = HORIZONTAL,length = 600, tickinterval=1)
        self.dscale.place(x=100, y=225)
        self.button = Button(self, text='Apply Values', command=self.runMotor, padx = 20, pady = 20)
        self.button.place(x=350, y=350)
        self.button3 = Button(self, text='Back To Main Window', command=self.destroy, padx=20, pady=20)
        self.button3.place(x=500, y=350)
        self.update()


    def tx_pulses(self, pi, GPIO, hertz, num, pulse_len=1):
       motSpeed = int((1/(self.dscale.get()))*2000)
       print(motSpeed)
       pulse_len = motSpeed
       assert num < 65536

       num_low = num % 256
       num_high = num // 256

       wf = []

       wf.append(pigpio.pulse(1<<GPIO, 0, pulse_len))
       wf.append(pigpio.pulse(0, 1<<GPIO, pulse_len))
       pi.wave_add_generic(wf)

       wid = pi.wave_create()

       if wid >= 0:
          pi.wave_chain([255, 0, wid, 255, 1, num_low, num_high])
          while pi.wave_tx_busy():
             time.sleep(0.1)
          pi.wave_delete(wid)

    def runMotor(self):
         motRevs = int(((self.scale.get())*400)*5.08)
         print(motRevs)
         pi.write(GPIO2,0)
         pi.write(GPIO3,1)
         self.tx_pulses(pi, GPIO, 1000, motRevs) # 250 pulses @ 1000 Hz
         pi.write(GPIO3,0)
         self.tx_pulses(pi, GPIO, 1000, motRevs) # 2391 pulses @ 5000 Hz
         pi.write(GPIO2,1)


mainWin = Tk()
mainWin.geometry('800x600')
mainWin.title('Main Window')
button2 = Button(mainWin, text='Go To Setup', command=ControlPanel, padx=20, pady=20)
button2.place(x=350, y=350)

mainWin.mainloop()
pi.stop()