Flutter如何使用flutter_downloader包下载文件

Question

你好我想使用flutter_downloader包下载一个文件我尝试使用示例中的代码 在文档中我有一个黑屏有时我有一个白屏，我不知道为什么我尝试只使用示例的一个功能我有一个错误并且它不起作用

 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);
  }

我得到了这个异常

[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

正如错误提示和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>

查看documentation了解更多信息