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最近我正在尝试编写 GUI 脚本，该脚本将从 QMC5883l 数字罗盘捕获数据并实时显示小 gui 中的数据，该脚本工作正常，没有错误，除非罗盘断开连接，OSError 很好地引发并且程序停止，我使用 try-catch 来解决这个问题，所以现在当异常引发它时表明指南针已断开连接，但是当指南针重新连接时它不会再次工作，就像它存储在 oserror 异常的代码中一样，我需要知道是否有任何方法可以错误结束时返回尝试脚本

我的代码在下面

# This Python file uses the following encoding: utf-8
import smbus            #import SMBus module of I2C
from time import sleep  #import sleep
import math
import sys
import os
from tkinter import *
#some MPU6050 Registers and their Address                         
Register_mode  = 0x09           #Address of mode register
Register_set_reset = 0x0b       #Addreas of set/reset period
X_axis_H    = 0x01              #Address of X-axis MSB data register
Z_axis_H    = 0x03              #Address of Z-axis MSB data register
Y_axis_H    = 0x05              #Address of Y-axis MSB data register
declination = 1.466          #define declination angle of location where measurement going to be done
pi          = 3.14159265359     #define pi value

def Magnetometer_Init():
        #Write to mode R`egister for selecting mode
        bus.write_byte_data(Device_Address, Register_mode, 0x1d)
        bus.write_byte_data(Device_Address, Register_set_reset , 0x01)
def read_raw_data(addr):
          #Read raw 16-bit value
        high = bus.read_byte_data(Device_Address, addr)
        low = bus.read_byte_data(Device_Address, addr-1)
        #concatenate higher and lower value
        value = ((high << 8) | low)

        #to get signed value from module
        if(value > 32768):
            value = value - 65536
        return value


bus = smbus.SMBus(1)    # or bus = smbus.SMBus(0) for older version boards
Device_Address = 0x0d   #QMC5883L magnetometer device address

Magnetometer_Init()     # initialize qMC5883L magnetometer 
print (" Reading Heading Angle")
window = Tk()
window.title("Welcome to LikeGeeks app")
window.geometry('350x200')
lbl = Label(window, text='heading angle')
lbl.grid(column=0, row=0)

def mainloop1():
        try:
        #Read Accelerometer raw value
                x = read_raw_data(X_axis_H)
                z = read_raw_data(Z_axis_H)
                y = read_raw_data(Y_axis_H)
        #Due to declination check for >360 degree
                heading = math.atan2(y, x) + declination        
                if(heading > 2*pi):
                        heading = heading - 2*pi

                #check for sign
                if(heading < 0):
                        heading = heading + 2*pi

                #convert into angle
                heading_angle = int(heading * 180/pi)
                lbl.configure(text=heading_angle)
                window.after(1,mainloop1)
          except OSError:
                  lbl.configure(text='compass disconnected')
window.after(0, mainloop1)      
window.mainloop()
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1 回答 1

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由于window.after(1, mainloop1)在block内部被调用try，一旦出现异常，就不会被执行，mainloop1()也不会再次被执行。

要克服它，只需将块window.after(1, mainloop1)移出try到末尾，mainloop1()如下所示：

def mainloop1():
    try:
        ...
        lbl.configure(text=heading_angle)
    except OSError as err:
        lbl.configure(text='compass disconnected')
    window.after(1, mainloop1)

然后window.after(1, mainloop1)即使发生异常也会执行。

于 2019-02-19T07:18:56.497 回答