Want to determine the width and height of an image in Flutter? With the new version of flutter old solution is obsolete. Now the addListener needs an ImageStreamListener.
If you already have an Image widget, you can read the ImageStream out of it by calling resolve on its ImageProvider.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | import 'dart:ui' as ui; import 'dart:async'; import 'package:flutter/material.dart'; import 'package:flutter/services.dart'; void main() { runApp(new MaterialApp( home: new MyHomePage(), )); } class MyHomePage extends StatelessWidget { Widget build(BuildContext context) { Image image = new Image.network('https://i.stack.imgur.com/lkd0a.png'); Completer<ui.Image> completer = new Completer<ui.Image>(); image.image .resolve(new ImageConfiguration()) .addListener((ImageInfo info, bool _) => completer.complete(info.image)); return new Scaffold( appBar: new AppBar( title: new Text("Image Dimensions Example"), ), body: new ListView( children: [ new FutureBuilder<ui.Image>( future: completer.future, builder: (BuildContext context, AsyncSnapshot<ui.Image> snapshot) { if (snapshot.hasData) { return new Text( '${snapshot.data.width}x${snapshot.data.height}', style: Theme.of(context).textTheme.display3, ); } else { return new Text('Loading...'); } }, ), image, ], ), ); } } |
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