一統天下 flutter - 資源: rootBundle - 訪問程序內資源
示例如下:
lib\resource\root_bundle.dart
/*
* rootBundle - 訪問程序內資源
*
* 在 pubspec.yaml 中配置需要打包的程序內資源，可以按文件配置，也可以按文件夾配置，類似如下
* flutter:
* assets:
* - assets/README.md
* - assets/son.jpg
* - assets/i18n/
*/
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import '../helper.dart';
class RootBundleDemo extends StatefulWidget {
const RootBundleDemo({Key? key}) : super(key: key);
@override
_RootBundleDemoState createState() => _RootBundleDemoState();
}
class _RootBundleDemoState extends State<RootBundleDemo> {
Future<String> _loadStringData() async {
/// rootBundle.loadString() 以文本的方式讀取程序內的指定的資源
return rootBundle.loadString('assets/README.md');
}
Future<Uint8List> _loadBinaryData() async {
/// rootBundle.load() 以二進制的方式讀取程序內的指定的資源
var byteData = await rootBundle.load("assets/son.jpg");
return byteData.buffer.asUint8List(byteData.offsetInBytes, byteData.lengthInBytes);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("title"),),
backgroundColor: Colors.orange,
body: Center(
child: Column(
children: [
FutureBuilder(
future: _loadStringData(),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasData) {
return MyTextSmall(snapshot.data!.substring(0, 200));
} else if (snapshot.hasError) {
return MyText('error: ${snapshot.error}');
}
}
return const MyText('loading');
},
),
FutureBuilder(
future: _loadBinaryData(),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasData) {
return Image.memory(snapshot.data!,
width: 50,
height: 50,
);
} else if (snapshot.hasError) {
return MyText('error: ${snapshot.error}');
}
}
return const MyText('loading');
},
),
],
),
),
);
}
}