Python 如果在函数中创建，为什么 Tkinter 图像不显示？
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Why does Tkinter image not show up if created in a function?
提问by thomas.winckell
This code works:
此代码有效：
import tkinter
root = tkinter.Tk()
canvas = tkinter.Canvas(root)
canvas.grid(row = 0, column = 0)
photo = tkinter.PhotoImage(file = './test.gif')
canvas.create_image(0, 0, image=photo)
root.mainloop()
It shows me the image.
它向我展示了图像。
Now, this code compiles but it doesn't show me the image, and I don't know why, because it's the same code, in a class:
现在，这段代码可以编译，但没有向我显示图像，我不知道为什么，因为它在一个类中是相同的代码：
import tkinter
class Test:
def __init__(self, master):
canvas = tkinter.Canvas(master)
canvas.grid(row = 0, column = 0)
photo = tkinter.PhotoImage(file = './test.gif')
canvas.create_image(0, 0, image=photo)
root = tkinter.Tk()
test = Test(root)
root.mainloop()
采纳答案by Bryan Oakley
The variable photois a local variable which gets garbage collected after the class is instantiated. Save a reference to the photo, for example:
该变量photo是一个局部变量，它在类被实例化后被垃圾收集。保存对照片的引用，例如：
self.photo = tkinter.PhotoImage(...)
If you do a Google search on "tkinter image doesn't display", the first result is this:
如果您对“tkinter 图像不显示”进行 Google 搜索，第一个结果是：
http://effbot.org/pyfaq/why-do-my-tkinter-images-not-appear.htm
http://effbot.org/pyfaq/why-do-my-tkinter-images-not-appear.htm
回答by Gabriel
Just add global photoas the first line inside the function.
只需添加global photo为函数内的第一行。
