我如何知道NetworkImage何时完成加载? [英] How do I tell when a NetworkImage has finished loading?
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问题描述
我有一个 NetworkImage ,我想知道何时完成加载。我该怎么办?
I have a NetworkImage and I'd like to know when it's finished loading. How do I do that?
推荐答案
您可以解决 c
ImageStream
和 addListener
到 ImageStream
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatefulWidget {
State createState() => new MyAppState();
}
class MyAppState extends State<MyApp> {
Image _image = new Image.network(
'https://flutter.io/images/flutter-mark-square-100.png',
);
bool _loading = true;
@override
void initState() {
_image.image.resolve(new ImageConfiguration()).addListener((_, __) {
if (mounted) {
setState(() {
_loading = false;
});
}
});
}
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: new Scaffold(
body: new Center(
child: _loading ? new Text('Loading...') : _image,
),
),
);
}
}
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