Flutter下载文件到手机下载目录

Question

我已经搜索过类似的问题和这个问题的答案，但到目前为止还没有找到任何具体的答案。 我正在尝试将下载的文件保存到我的内部手机存储中。最好是下载文件夹...我正在使用 d i o 和路径提供程序。 尝试使用“获取外部存储目录”。但即使在下载之后，我也无法在设备中的任何位置找到该文件。 请问如何指定下载路径到 /storage/emulated/0/Download 之类的东西

Answer 1

您可以在下面复制粘贴运行完整代码
此示例代码下载带有Dio 的pdf 文件并保存到Downloads 目录
第1步：downloads_path_provider已经被所有者归档，你可以使用包https://pub.dev/packages/ext_storage
代码sn-p

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

第二步：在AndroidManifest.xml中添加权限

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

第三步：pubspec.yaml，注意permission_handler是4.4.0

dependencies:
  flutter:
    sdk: flutter
  dio: any
  permission_handler: 4.4.0
  ext_storage: any

第 4 步：Dio 下载文件

Future download2(Dio dio, String url, String savePath) async {
    try {
      Response response = await dio.get(
        url,
        onReceiveProgress: showDownloadProgress,
        //Received data with List<int>
        options: Options(
            responseType: ResponseType.bytes,
            followRedirects: false,
            validateStatus: (status) {
              return status < 500;
            }),
      );
      print(response.headers);
      File file = File(savePath);
      var raf = file.openSync(mode: FileMode.write);
      // response.data is List<int> type
      raf.writeFromSync(response.data);
      await raf.close();
    } catch (e) {
      print(e);
    }
  }

输出

I/flutter (13605): full path /storage/emulated/0/Download/test.pdf
I/flutter (13605): 62%
I/flutter (13605): 100%

完整代码

import 'package:flutter/material.dart';
import 'package:dio/dio.dart';
import 'package:ext_storage/ext_storage.dart';
import 'dart:io';
import 'package:permission_handler/permission_handler.dart';

final imgUrl =
    "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf";

var dio = Dio();

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

  void getPermission() async {
    print("getPermission");
    Map<PermissionGroup, PermissionStatus> permissions =
        await PermissionHandler().requestPermissions([PermissionGroup.storage]);
  }

  @override
  void initState() {
    getPermission();
    super.initState();
  }

  Future download2(Dio dio, String url, String savePath) async {
    try {
      Response response = await dio.get(
        url,
        onReceiveProgress: showDownloadProgress,
        //Received data with List<int>
        options: Options(
            responseType: ResponseType.bytes,
            followRedirects: false,
            validateStatus: (status) {
              return status < 500;
            }),
      );
      print(response.headers);
      File file = File(savePath);
      var raf = file.openSync(mode: FileMode.write);
      // response.data is List<int> type
      raf.writeFromSync(response.data);
      await raf.close();
    } catch (e) {
      print(e);
    }
  }

  void showDownloadProgress(received, total) {
    if (total != -1) {
      print((received / total * 100).toStringAsFixed(0) + "%");
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            RaisedButton.icon(
                onPressed: () async {
                  String path =
                      await ExtStorage.getExternalStoragePublicDirectory(
                          ExtStorage.DIRECTORY_DOWNLOADS);
                  //String fullPath = tempDir.path + "/boo2.pdf'";
                  String fullPath = "$path/test.pdf";
                  print('full path ${fullPath}');

                  download2(dio, imgUrl, fullPath);
                },
                icon: Icon(
                  Icons.file_download,
                  color: Colors.white,
                ),
                color: Colors.green,
                textColor: Colors.white,
                label: Text('Dowload')),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

Answer 2

我还没有测试过，但是如果你想将下载的文件保存到下载目录，有一个包：downloads_path_provider

如果您遇到问题，可以改用path_provider 包。 它使您可以访问多个设备目录。