Python tkinter 代码在 function 内时不运行

Question

def display_rain():
    rain_image = Image.open("./images/rain_jpeg.jpg")
    rain_resized = rain_image.resize((250,250), Image.ANTIALIAS)
    rain_tk = ImageTk.PhotoImage(rain_resized)
    rain_label = tk.Label(root, image = rain_tk)
    rain_label.grid(row = 0, column = 0)
    rain_label.pack()

display_rain()

The code runs fine when outside of a function but doesn't appear to run at all when inside it. I've tried restarting Python and renaming the function.

Answer 1

Your image is being garbage collected. This works.

import tkinter as tk
from PIL import Image, ImageTk


root = tk.Tk()
root.geometry("800x600")

#store all images in this dict so garbage collection will leave them alone
#it doesn't have to be named "images"; it just has to be a dict
images = dict()


def display_rain(row=0, column=0):
    #create and store the image if it doesn't exist
    if 'rain_tk' not in images:
        #unless you are making mips of this image you should probably  
        #~make it the proper size and get rid of the resize part
        image = Image.open("./images/rain_jpeg.jpg").resize((250,250), Image.ANTIALIAS)
        #you can add a name to reference the image by
        #this makes it cleaner than accessing the dict directly
        images['rain_tk'] = ImageTk.PhotoImage(image, name='rain')
        
    #make and return the label, in case you want to grid_forget it or change the image
    label = tk.Label(root, image='rain') #instead of image=images['rain_tk']
    label.grid(row=row, column=column)
    return label
    
#you can easily display this wherever you want by filling in the row and column arguments
#as an example, this would be displayed at row1 column2
rain_lbl = display_rain(1, 2)
      
root.mainloop()