Flutter 如何使用flutter_downloader package下载文件

Question

您好，我想使用flutter_downloader package 下载文件示例我有一个错误，它没有工作

 import 'dart:isolate';
import 'dart:ui';

import 'package:flutter/material.dart';
import 'dart:async';
import 'package:path_provider/path_provider.dart';
import 'package:flutter_downloader/flutter_downloader.dart';
import 'package:permission_handler/permission_handler.dart';
import 'dart:io';

const debug = true;


class download extends StatefulWidget with WidgetsBindingObserver {
  final TargetPlatform platform;

  download({Key key, this.title, this.platform}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<download> {



  String _localPath;

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


   WidgetsFlutterBinding.ensureInitialized();
   FlutterDownloader.initialize(
       debug: true // optional: set false to disable printing logs to console
   );
 
  }

  @override
  void dispose() {
    super.dispose();
  }


  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('bonjour'),
      ),
    body:FlatButton(
    child:Text('bbbbb'),
    onPressed: _requestDownload,
    )
    );
  }



  void _requestDownload() async {
     await FlutterDownloader.enqueue(
        url:'http://barbra-coco.dyndns.org/student/learning_android_studio.pdf' ,
        headers: {"auth": "test_for_sql_encoding"},
        savedDir: _localPath,
        showNotification: true,
        openFileFromNotification: true);
  }

我得到了这个例外

[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: 'package:flutter_downloader/src/downloader.dart': Failed assertion: line 73 pos 12: '_initialized': FlutterDownloader.initialize() must be called first

我在问是否有解释或解决方案或带有解释和详细信息的工作示例谢谢

Answer 1

正如错误所暗示的那样，并且根据您在使用前必须初始化的文档，

叫这个

WidgetsFlutterBinding.ensureInitialized();
FlutterDownloader.initialize(
  debug: true // optional: set false to disable printing logs to console
);

并在 AndroidManifest 中添加以下代码

<provider
    android:name="vn.hunghd.flutterdownloader.DownloadedFileProvider"
    android:authorities="${applicationId}.flutter_downloader.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths"/>
</provider>

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