Tkinter没有按预期将图像放在按钮上

Question

I'm creating images using PIL, not saving them anywhere because they will be different every time and trying to put those images on buttons. The problem is, for some reason that only the last image gets put on the button. This is my code:

from PIL import ImageDraw
from PIL import ImageFont
from Tkinter import *

master = Tk()
W, H = (70,70)

from PIL import Image
from PIL import ImageTk

def fun(meth):
    print meth
    return
for i in range(0,5):
    img = Image.new("RGB", (W, H), (255,0,0))
    draw = ImageDraw.Draw(img)
    text_string = str(i)+','+str(i+1)
    font = ImageFont.truetype("arial.ttf", 25)
    w, h = draw.textsize(text_string, font=font)
    draw.text(((W-w)/2,(H-h)/2), str(i)+','+str(i+1),(0,0,0), font=font )


    imagetk = ImageTk.PhotoImage(img)
    b = Button(master, image=imagetk, command=lambda method=text_string: fun(method))
    b.grid(row=0, column=i, padx=20)

    #img.save(path+'.png', "PNG")

master.mainloop()

For me, output for this program looks like this

I'm saving images to disk in the end of the loop and I'm seeing other images created just as expected, but for some reason they don't get put on the other buttons. Also I just now noticed that other buttons don't even respond to click, only the last one behaves as expected.

Answer 1

You didn't create an external reference. I simply added a refs list and now it works fine:

refs = [] # new
for i in range(0,5):
    img = Image.new("RGB", (W, H), (255,0,0))
    draw = ImageDraw.Draw(img)
    text_string = str(i)+','+str(i+1)
    font = ImageFont.truetype("arial.ttf", 25)
    w, h = draw.textsize(text_string, font=font)
    draw.text(((W-w)/2,(H-h)/2), str(i)+','+str(i+1),(0,0,0), font=font )


    imagetk = ImageTk.PhotoImage(img)
    b = Button(master, image=imagetk, command=lambda method=text_string: fun(method))
    b.grid(row=0, column=i, padx=20)
    refs.append(imagetk) # new