Tkinter气象应用报NameError：变量未定义，如何解决？

错误根源 #

1. 变量作用域问题：inside_temp_display等Label变量是在按钮点击函数内部定义的局部变量，clear_display函数无法访问这些局部变量，因此触发NameError。
2. 控件重复创建：每次点击按钮都会新建一组Label，导致界面控件叠加，旧控件也无法被后续操作修改。

修复方案 #

1. 在GUI初始化时提前创建所有需要的Label控件，设置初始文本为空，并将这些变量设为全局变量，确保所有函数都能访问。
2. 按钮点击函数不再新建Label，而是直接更新已有Label的文本内容。
3. 调整clear_display函数，直接操作全局Label控件清空文本。

修改后的完整代码 #

from sense_emu import SenseHat
from tkinter import *
import requests
import datetime as datetime

sense = SenseHat()

# ---- INSIDE TEMPERATURE, HUMIDTY AND PRESSURE ---- #
inside_temp = round(sense.get_temperature(), 2)
inside_humid = round(sense.get_humidity(), 2)
inside_press = round(sense.get_pressure(), 2)

# ---- OUTSIDE TEMPERATURE, HUMIDTY AND PRESSURE ---- #
url = 'https://api.open-meteo.com/v1/forecast?latitude=45.8144&longitude=15.978&hourly=temperature_2m,relativehumidity_2m,surface_pressure&timezone=Europe%2FBerlin&forecast_days=1'
response = requests.get(url)
data = response.json()

# ---- CALCULATE DIFFERENCES ---- #
outside_temp_hourly = data['hourly']['temperature_2m']
outside_humid_hourly = data['hourly']['relativehumidity_2m']
outside_press_hourly = data['hourly']['surface_pressure']

temp_diff = [round(temp - inside_temp, 2) for temp in outside_temp_hourly]
humid_diff = [round(hum - inside_humid, 2) for hum in outside_humid_hourly]
press_diff = [round(press - inside_press, 2) for press in outside_press_hourly]

# ---- GET CURRENT HOUR ---- #
now = datetime.datetime.now()
current_hour = now.hour

# 全局声明显示用的Label变量
inside_temp_display = None
outside_temp_display = None
diff_temp_display = None
inside_humid_display = None
outside_humid_display = None
diff_humid_display = None
inside_press_display = None
outside_press_display = None
diff_press_display = None

# ---- FUNCTIONS FOR THE BUTTONS ---- #
def show_current_temp():
    clear_display()
    inside_temp_display.config(text=f"Current inside temperature: {inside_temp}°C.")
    outside_temp_display.config(text=f"Current outside temperature: {outside_temp_hourly[current_hour]}°C.")
    diff_temp_display.config(text=f"Difference in temperature is: {abs(temp_diff[current_hour])}°C.")

def show_current_humid():
    clear_display()
    inside_humid_display.config(text=f"Current inside humidity: {inside_humid}%.")
    outside_humid_display.config(text=f"Current outside humidity: {outside_humid_hourly[current_hour]}%.")
    diff_humid_display.config(text=f"Difference in humidty is: {abs(humid_diff[current_hour])}%.")

def show_current_press():
    clear_display()
    inside_press_display.config(text=f"Current inside pressure: {inside_press}hPa.")
    outside_press_display.config(text=f"Current outside pressure: {outside_press_hourly[current_hour]}hPa.")
    diff_press_display.config(text=f"Difference in pressure is: {abs(press_diff[current_hour])}hPa.")

def clear_display():
    inside_temp_display.config(text="")
    outside_temp_display.config(text="")
    diff_temp_display.config(text="")
    inside_humid_display.config(text="")
    outside_humid_display.config(text="")
    diff_humid_display.config(text="")
    inside_press_display.config(text="")
    outside_press_display.config(text="")
    diff_press_display.config(text="")

# ---- MAIN GUI PROGRAM ---- #
def gui():
    global inside_temp_display, outside_temp_display, diff_temp_display
    global inside_humid_display, outside_humid_display, diff_humid_display
    global inside_press_display, outside_press_display, diff_press_display
    
    root = Tk()
    root.title("Weather")
    root.geometry("700x600")
    
    title = Label(root, text="Weather info", font=("Arial", 20), pady=20)
    title.grid(row=0, column=1)
    
    temp_button = Button(root, text="Display temperature", command=show_current_temp)
    temp_button.grid(row=1, column=0, padx=40)
    
    humid_button = Button(root, text="Display humidity", command=show_current_humid)
    humid_button.grid(row=1, column=1, padx=45, pady=20)
    
    press_button = Button(root, text="Display pressure", command=show_current_press)
    press_button.grid(row=1, column=2, padx=40)
    
    # 初始化所有显示用的Label，设置为空文本
    inside_temp_display = Label(root, pady=5)
    inside_temp_display.grid(row=2, column=1)
    
    outside_temp_display = Label(root, pady=5)
    outside_temp_display.grid(row=3, column=1)
    
    diff_temp_display = Label(root, pady=5)
    diff_temp_display.grid(row=4, column=1)
    
    inside_humid_display = Label(root, pady=5)
    inside_humid_display.grid(row=2, column=1)
    
    outside_humid_display = Label(root, pady=5)
    outside_humid_display.grid(row=3, column=1)
    
    diff_humid_display = Label(root, pady=5)
    diff_humid_display.grid(row=4, column=1)
    
    inside_press_display = Label(root, pady=5)
    inside_press_display.grid(row=2, column=1)
    
    outside_press_display = Label(root, pady=5)
    outside_press_display.grid(row=3, column=1)
    
    diff_press_display = Label(root, pady=5)
    diff_press_display.grid(row=4, column=1)
    
    root.mainloop()

# 启动GUI
gui()

注：已修复原代码中show_current_temp函数里误写的inside_temp_display.grid(row=4, column=1)错误，改为正确的diff_temp_display.grid(...)逻辑。

内容的提问来源于stack exchange，提问作者SolidOpt