Python 如何在Kivy的AsyncImage中检测图片下载结束？

我正在写一个简单的应用程序，像这样：

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.image import AsyncImage


class Application(App):

    def build(self):
        box_layout = BoxLayout(orientation='vertical')
        img = AsyncImage(
            source='http://pl.python.org/forum/Smileys/default/cheesy.gif')

        box_layout.add_widget(img)
        return box_layout

    def __on_image_loaded(self):
        print('Very importatn stuff executed afer image has been downloaded by img widget.')

app = Application()
app.run()

如何检测AsyncImage小部件从给定URL下载图片的行为

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或者，我可以自己编写下载线程并使用图像小部件，但在这种情况下，我可以如何将原始字节从内存加载到图像小部件以将其显示为图片？

您可以使用

img.\u coreimage.bind（on\u load=self.on\u Image\u load）

：

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.image import AsyncImage


class Application(App):

    def build(self):
        box_layout = BoxLayout(orientation='vertical')
        img = AsyncImage(source='http://pl.python.org/forum/Smileys/default/cheesy.gif')
        img._coreimage.bind(on_load=self.on_image_loaded)

        box_layout.add_widget(img)
        return box_layout

    def on_image_loaded(self, *args):
        print('Very importatn stuff executed afer image has been downloaded by img widget.')

app = Application()
app.run()