打印到 Tkinter 标签答案

【问题标题】：Print to Tkinter label打印到 Tkinter 标签
【发布时间】：2020-04-29 14:56:13
【问题描述】：

我正在尝试使用 Openweathermap API 的 Tkinter 进行几天的天气预报。在第一个函数：“def format_response(weather)”中，如果我使用 print(final_str)，Python Shell 上的结果很好，但标签上没有显示任何内容。如果我使用 return(final_str)，标签只显示一天的天气。如何在标签中显示整个结果？

谢谢你。

import tkinter as tk
from tkinter import font
from PIL import ImageTk, Image
import requests
from datetime import datetime

HEIGHT = 700
WIDTH = 700


def format_response(weather):

    for i in range(10):

        dt_txt = weather['list'][i]['dt']
        date = (datetime.fromtimestamp(dt_txt)).strftime('%d-%b-%Y %H:%M:%S')

        desc = weather['list'][i]['weather'][0]['description']

        temp_min = weather['list'][i]['main']['temp_min']

        temp_max = weather['list'][i]['main']['temp_max']

        final_str = 'Date: %s \nConditions: %s \nMin.Temperature(Celsius): %s\nMax.Temperature(Celsius): %s' %(date, desc, temp_min, temp_max)

        return(final_str)

def get_weather(city):
    api_key = 'a4aa5e3d83ffefaba8c00284de6ef7c3'
    url = 'https://api.openweathermap.org/data/2.5/forecast' # can switch between forecast and weather
    params = {'APPID': api_key, 'q': city, 'units': 'metric'}
    response = requests.get(url, params = params)
    weather = response.json()

    label['text'] = format_response(weather)


root = tk.Tk()

# CANVAS SIZE
canvas = tk.Canvas(root, height = HEIGHT, width = WIDTH)
canvas.pack()

# BACKGROUND
background_image = ImageTk.PhotoImage(Image.open("D:/Documents/Python/GUI/Weather App/beach.png"))
background_label = tk.Label(root, image = background_image)
background_label.place(relwidth = 1, relheight = 1)

# FRAME, UPPER
frame = tk.Frame(root, bg = '#b1cfff', bd = 5)
frame.place(relx = 0.5, rely = 0.15, relwidth = 0.80, relheight = 0.05, anchor = 'n') 
# use value '1' to fill entire box


# ENTRY/INPUT
entry = tk.Entry(frame, bg='#fce300', font = 40)
entry.place(relx = 0.0, rely = 0, relwidth = 0.75, relheight = 1)

# BUTTON
button = tk.Button(frame, text = "SEARCH", font = 40, bg = 'black', fg = 'yellow', command = lambda: get_weather(entry.get()))
button.place(relx = 0.758, rely = 0, relwidth = 0.24, relheight = 1)


# FRAME, LOWER
lower_frame = tk.Frame(root, bg = '#b1cfff', bd = 5)
lower_frame.place(relx = 0.5, rely = 0.25, relwidth = 0.80, relheight = 0.6, anchor = 'n')

# LABEL, FRAME, LOWER
label = tk.Label(lower_frame, font = ('courier new',10), bg = '#fce300', anchor = 'nw', justify = 'left')
label.place(relwidth = 1, relheight = 1)

root.mainloop()

【问题讨论】：

带有无条件return 的for 循环毫无意义；只有循环的第一次迭代才会发生，一旦它达到return，函数就完成。您需要从每次迭代中累积文本，然后在循环之外返回。
请考虑从帖子中修改您的 API 密钥

标签： python tkinter

【解决方案1】：

尝试将 10 final_strs 收集到一个列表中，然后返回它。然后可以在设置标签之前将列表组装成一个巨大的多行字符串：

def format_response(weather):
    ten_day = []
    for i in range(10):
        ... [stuff] ...
        ten_day.append(final_str)
    return ten_day

和

    label['text'] = '\n'.join(format_response(weather))

【讨论】：