이미지파일 다운로드및 FutureBuilder 를 이용한 화면에 나타내기 소스

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> {

  bool downloading = false;

  var progressString = "";

  String? file = "";

 

TextEditingController? _editingController;

 

@override

void initState() {

  super.initState();

  _editingController = new TextEditingController(text: 'https://www.motherjones.com/wp-content/uploads/2019/12/Getty121719.jpg?w=1200&h=630&crop=1');

}

 

  Future<void> downloadFile() async {

 

    Dio dio = Dio();

    try {

      var dir = await getApplicationDocumentsDirectory();

      await dio.download(_editingController!.value.text, '${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: TextField(

          controller: _editingController,

          style: TextStyle(color: Colors.white),

          keyboardType: TextInputType.text,

          decoration: InputDecoration(hintText: 'url 입력하세요'),

        ),

      ),

      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('데이터 없음');

                      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 as Widget;

                        }

                    }

                    return Text('데이터 없음');

                  },

                  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();

    new FileImage(file).evict();

    if (exist) {

      return Center(

        child: Column(

          children: <Widget>[Image.file(file)],

        ),

      );

    } else {

      return Text('No Data');

    }

  }

}