Flutter 通过 path_provider 包获取外部存储目录和 MediaStore

Question

我需要打开并保存设备上可能存在的简单文本文件。例如在文档、下载等中。只要文件可用于其他程序，在 Android 术语中，它就是“外部存储”

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path_provider提供了几种方法。其中之一getExternalStorageDirectory()。安卓文档说：

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此方法已在 API 级别 29 中弃用。为了提高用户隐私，\n不推荐直接访问共享/外部存储设备。当\n应用程序定位 Build.VERSION_CODES.Q链接时

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如果我使用方法path_provider

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getExternalStorageDirectory()\xe2\x86\x92 /storage/emulated/0/Android/data/myapp.name/files \n getApplicationDocumentsDirectory()\xe2\x86\x92 /data/user/0/myapp.name/app_flutter

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getExternalStorageDirectories(type: StorageDirectory.documents)返回列表，其中包含

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/storage/emulated/0/Android/data/myapp.name/files/Documents

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/storage/1CEE-4019/Android/data/myapp.name/files/Documents

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在我的 Android 模拟器（Api 30）上，真实的外部文档位于

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/存储/模拟/0/文档

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/存储/模拟/0/下载

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我怎样才能访问它们？据我了解，没有其他选择path_provider

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Answer 1

您可以复制粘贴运行下面的完整代码
您可以使用包https://pub.dev/packages/ext_storage
代码片段

String pathDownload = await ExtStorage.getExternalStoragePublicDirectory(
    ExtStorage.DIRECTORY_DOWNLOADS);
print(pathDownload);

String pathDoc = await ExtStorage.getExternalStoragePublicDirectory(
    ExtStorage.DIRECTORY_DOCUMENTS);
print(pathDoc);

输出

I/flutter ( 7361): /storage/emulated/0/Download
I/flutter ( 7361): /storage/emulated/0/Documents

完整代码

import 'package:flutter/material.dart';
import 'package:ext_storage/ext_storage.dart';

void main() {
  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();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() async {
    String pathDownload = await ExtStorage.getExternalStoragePublicDirectory(
        ExtStorage.DIRECTORY_DOWNLOADS);
    print(pathDownload);

    String pathDoc = await ExtStorage.getExternalStoragePublicDirectory(
        ExtStorage.DIRECTORY_DOCUMENTS);
    print(pathDoc);

    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}