我想从Flutter应用程序的互联网路径中获取视频大小

问题描述

我正在尝试获取视频文件的大小，并将其用作LinearPercentIndicator中的百分比。 根据我的搜索，我找到了一个代码，但是对于android，我该如何在Flutter上做类似的事情。

final URL uri=new URL("http://your_url.com/file.mp4");
URLConnection connection;
try
{
connection=uri.openConnection();
connection.connect();
final String contentLengthStr=ucon.getHeaderField("content-length");
// do whatever
}

catch(final IOException exception)
{
}

PS：我正在使用FFmpeg下载。

解决方法

例如，使用dio插件

dio使用大文件下载器

URL链接：https://pub.dev/packages/dio

例如

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:dio/dio.dart';
import 'package:path_provider/path_provider.dart';

class LargeFileMain extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _LargeFileMain();
}

class _LargeFileMain extends State<LargeFileMain> {
  final imgUrl =
      'http://your_url.com/file.mp4';
  bool downloading = false;
  var progressString = "";
  var file;

  Future<void> downloadFile() async {
    Dio dio = Dio();
    try {
      var dir = await getApplicationDocumentsDirectory();
      await dio.download(imgUrl,'${dir.path}/myimage.jpg',onReceiveProgress: (rec,total) {
        print('Rec: $rec,Total: $total');
        file = '${dir.path}/myimage.jpg';
        setState(() {
          downloading = true;
          progressString = ((rec / total) * 100).toStringAsFixed(0) + '%';
        });
      });
    } catch (e) {
      print(e);
    }
    setState(() {
      downloading = false;
      progressString = 'Completed';
    });
    print('Download completed');
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Large File Example'),),body: Center(
          child: downloading
              ? Container(
                  height: 120.0,width: 200.0,child: Card(
                    color: Colors.black,child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
                        CircularProgressIndicator(),SizedBox(
                          height: 20.0,Text(
                          'Downloading File: $progressString',style: TextStyle(
                            color: Colors.white,)
                      ],)
              : FutureBuilder(
                  builder: (context,snapshot) {
                    switch (snapshot.connectionState) {
                      case ConnectionState.none:
                        print('none');
                        return Text('No Data');
                      case ConnectionState.waiting:
                        print('waiting');
                        return CircularProgressIndicator();
                      case ConnectionState.active:
                        print('active');
                        return CircularProgressIndicator();
                      case ConnectionState.done:
                        print('done');
                        if (snapshot.hasData) {
                          return snapshot.data;
                        }
                    }
                    return Text('No Data');
                  },future: downloadWidget(file),)),floatingActionButton: FloatingActionButton(
        onPressed: () {
          downloadFile();
        },child: Icon(Icons.file_download),);
  }

  Future<Widget> downloadWidget(String filePath) async {
    File file = File(filePath);
    bool exist = await file.exists();
    if (exist) {
      return Center(
        // your video file using widget
      );
    } else {
      return Text('No Data');
    }
  }
}