-
Image.asset - 用于从资源目录的显示图片
-
Image.network - 用于从网络上显示图片
-
Image.file - 用于从文件里显示图片
-
Image.memory - 用于从内存里（Uint8List）显示图片
3.1 Image.asset
设置pubspec.yaml
-
在项目路径下，新建images文件夹，并将图片
flutter.png放到images路径下 -
在pubspec.yaml 文件中添加assets，如上图，注意images的路径(间隔两个字母)
flutter:
assets:
- images/flutter.png
代码设置(lib/main.dart)
Image.asset(“images/flutter.png”),
3.2 Image.network
Image.network(“https://flutter.dev/assets/flutter-lockup-1caf6476beed76adec3c477586da54de6b552b2f42108ec5bc68dc63bae2df75.png”),
7)3.3 Image.file
添加path_provider依赖
在pubspec.yaml 文件中添加path_provider依赖
dependencies:
path_provider: ^1.6.26
然后，执行Pub get获取path_provider依赖
path_provider说明
对于Android系统
Directory tempDir = await getTemporaryDirectory();
String tempPath = tempDir.path;
Directory appDocDir = await getApplicationDocumentsDirectory();
String appDocPath = appDocDir.path;
String storageDir = (await getExternalStorageDirectory()).path;
加载sd卡图片需要读写权限，在AndroidManifest.xml中添加
打印文件路径
Future main() async {
String appDir = (await getApplicationDocumentsDirectory()).path;
String tempDir = (await getTemporaryDirectory()).path;
String storageDir = (await getExternalStorageDirectory()).path;
print(“appDir==$appDir”);
print(“tempDir==$tempDir”);
print(“storageDir==$storageDir”);
}
输出结果
I/flutter (10148): appDir==/data/user/0/com.example.flutter_image/app_flutter
I/flutter (10148): tempDir==/data/user/0/com.example.flutter_image/cache
I/flutter (10148): storageDir==/storage/emulated/0/Android/data/com.example.flutter_image/files
将要显示的图片导入到手机中
完整代码(lib/main.dart)
import ‘dart:convert’;
import ‘dart:io’;
import ‘dart:typed_data’;
import ‘package:flutter/material.dart’;
import ‘package:path_provider/path_provider.dart’;
Future main() async {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: ‘Flutter Demo’,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: ‘Flutter Demo Home Page’),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
File file;
class _MyHomePageState extends State {
int _counter = 0;
String _storageDir = ‘’;
File file;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
_getLocalFile();
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Image.file(File(_storageDir+"/flutter.png")),
Image.file(File("$_storageDir/flutter.png")),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: ‘Increment’,
child: Icon(Icons.add),
),
);
}
_getLocalFile() async {
String appDir = (await getApplicationDocumentsDirectory()).path;
String tempDir = (await getTemporaryDirectory()).path;
String storageDir = (await getExternalStorageDirectory()).path;
ctionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: ‘Increment’,
child: Icon(Icons.add),
),
);
}
_getLocalFile() async {
String appDir = (await getApplicationDocumentsDirectory()).path;
String tempDir = (await getTemporaryDirectory()).path;
String storageDir = (await getExternalStorageDirectory()).path;