如何在Kivy中的AsyncImage中檢測圖片下載結束？

Question

我正在寫一個像這樣的簡單應用：

#!/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()

如何檢測到AsyncImage小部件已從給定的URL下載圖片結束？

另外，我可以自己編寫下載線程並使用Image小部件，但是在這種情況下，我該怎么做才能將內存中的原始字節加載到Image小部件中以將它們顯示為圖片？

Answer 1

您可以使用img._coreimage.bind(on_load=self.on_image_loaded) ：

#!/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()