在函数中显示python中的图像[重复]

Question

我正在尝试从链接中显示图像，下面的代码可以正常工作并按预期显示图像

from tkinter import *
from PIL import ImageTk,Image
import requests
from io import BytesIO

root = Tk()
root.title('Weather')
root.iconbitmap('icon.ico')
root.geometry("450x300")

image_link = requests.get('https://assets.weatherstack.com/images/wsymbols01_png_64/wsymbol_0006_mist.png')
my_img = ImageTk.PhotoImage(Image.open(BytesIO(image_link.content)))
image_link  =Label(root, image = my_img)
image_link.grid(row = 0, column = 0 )

root.mainloop()

但现在我必须稍微更新一下我的代码，并且必须把它放在一个函数中

from tkinter import *
from PIL import ImageTk,Image
import requests
from io import BytesIO

root = Tk()
root.title('Weather')
root.iconbitmap('icon.ico')
root.geometry("450x300")

def image_func():
    image_link = requests.get('https://assets.weatherstack.com/images/wsymbols01_png_64/wsymbol_0006_mist.png')
    my_img = ImageTk.PhotoImage(Image.open(BytesIO(image_link.content)))
    image_label  =Label(root, image = my_img)
    image_label.grid(row = 0, column = 0 )

image_func()
root.mainloop()

上面没有显示图像，所以我尝试将图像标签放在框架内，但这只是显示框架内没有任何内容，powershell 或 cmd 也没有显示任何错误

Answer 1

您在函数内创建的所有对象都是本地的。所以这些对象在函数退出时被删除。您需要一种方法来保持这些对象存在。例如通过使用全局变量

from tkinter import *
from PIL import ImageTk,Image
import requests
from io import BytesIO

root = Tk()
root.title('Weather')
root.iconbitmap('icon.ico')
root.geometry("450x300")

my_img = None
image_label = None

def image_func():
    global my_img, image_label

    image_link = requests.get('https://assets.weatherstack.com/images/wsymbols01_png_64/wsymbol_0006_mist.png')
    my_img = ImageTk.PhotoImage(Image.open(BytesIO(image_link.content)))
    image_label  = Label(root, image = my_img)
    image_label.grid(row = 0, column = 0 )

image_func()

root.mainloop()

另一种方法是从函数中返回对象并保留返回值

from tkinter import *
from PIL import ImageTk, Image
import requests
from io import BytesIO

root = Tk()
root.title('Weather')
root.iconbitmap('icon.ico')
root.geometry("450x300")

def image_func():
        
    image_link = requests.get('https://assets.weatherstack.com/images/wsymbols01_png_64/wsymbol_0006_mist.png')
    my_img = ImageTk.PhotoImage(Image.open(BytesIO(image_link.content)))
    image_label = Label(root, image=my_img)
    image_label.grid(row=0, column=0)

    return my_img, image_label


my_img, image_label = image_func()

root.mainloop()