Python:全局变量不受函数影响/更改

Question

我正在开发的烧瓶应用程序有问题

名为buttonNum的全局变量应该随着button（）的每次调用而更改；但是，ardCom（）中的buttonNum不受影响，不承认button（）对其所做的更改。我在网上找到了一些关于如何使用globals的例子，从我所知道的情况来看，这应该是可行的

我感谢所有的帮助。 谢谢

import time
import json
import serial
import flask
from multiprocessing import Process
from flask import Flask, request, render_template, make_response

buttonNum = 0
app = Flask(__name__)

@app.route('/')
def default():
    headers = {'Content-Type': 'text/html'}
    return make_response(render_template('index.html'),200,headers)

@app.route('/setup', methods=['POST'])
def setup():
    data = request.get_json
    return {'result' : "Success"}

@app.route('/button', methods=['POST'])
def button():
    global buttonNum
    buttonNum= int(request.form['number'])
    typeOf = int(request.form['type'])
    value = int(request.form['value'])
    return "success"

def ardCom():
    global buttonNum
    county = 1
    ph = b''
    ph = ser.read()

    if ph == b'S':
        ser.write(ph)
        while (ph != b'E'):
            ph = ser.read()
            if ph == b'E':
                ser.write(ph)
                break
            #print(str(buttonNum))
            if ph == b'\x00' and buttonNum != county:
                writeOut(b'\x00')
                county += 1
            if ph  == b'\x01' or buttonNum == county:
                writeOut(b'\x01')
                print("Button", end = " ")
                print(county, end = " ")
                print("has been pressed.")
                county += 1

def writeOut(datByte):
    ser.write(datByte)

def runApi():
    app.run(host='0.0.0.0')

if __name__  == '__main__':
    ser = serial.Serial('/dev/ttyACM0', 9600, timeout=1)
    ser.flush()
    time.sleep(1)
    apiProcess = Process(target=runApi)
    apiProcess.start()
    while True:
        ardCom()

Answer 1

当flask服务器运行时，它可能会运行一些实例。要使代码正常工作，可以将值存储在文件（如json）或数据库中