In this post we will learn download files from Internet and view downloaded files from the listView. To download files inside the app using Dio package. We are going to store the downloaded file in the Application Directory using the path_provider package
After downloading file to view, we are using the syncfusion_flutter_pdfviewer plugin
In this Post we will cover
Let's get started
Step 1: Create a Flutter application
Step 2: add required dependencies in pubspec.yaml file
dependencies:
flutter:
sdk: flutter
dio: ^4.0.0
path_provider: ^2.0.2
permission_handler :
syncfusion_flutter_pdfviewer:
ndialog: ^4.1.0
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Check Permissions:
We are suing the Permission_handler plugin to check the permissions were granted or not, if permissions not granted then we are rewuesting the required permissions by below code
requestWritePermission() async {
if (await Permission.storage.request().isGranted) {
setState(() {
_allowWriteFile = true;
});
}else
{
Map<Permission, PermissionStatus> statuses = await [
Permission.storage,
].request();
}
}
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Create a Folder Directory path
To store downloaded files we are creating a folder in the storage by below code
Future<String>getDirectoryPath() async
{
Directory appDocDirectory = await getApplicationDocumentsDirectory();
Directory directory= await new Directory(appDocDirectory.path+'/'+'dir').create(recursive: true);
return directory.path;
}
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Download file:
Now its time to download the selected file from listview. To download file from internet we are using the dio package. The code will be like below
Future downloadFile(String url,path) async {
if(!_allowWriteFile)
{
requestWritePermission();
}
try{
ProgressDialog progressDialog=ProgressDialog(context,dialogTransitionType: DialogTransitionType.Bubble,title: Text("Downloading File"));
progressDialog.show();
await dio.download(url, path,onReceiveProgress: (rec,total){
setState(() {
isLoading=true;
progress=((rec/total)*100).toStringAsFixed(0)+"%";
progressDialog.setMessage(Text( "Dowloading $progress"));
});
});
progressDialog.dismiss();
}catch( e)
{
print(e.toString());
}
}
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View the Downloaded PDF
To view the downloaded PDF files we are using the syncfusion PDF library .
class PDFScreen extends StatelessWidget {
String pathPDF = "";
PDFScreen(this.pathPDF);
final GlobalKey<SfPdfViewerState> _pdfViewerKey = GlobalKey();
@override
Widget build(BuildContext context) {
return SfPdfViewer.file(
File(pathPDF),
key: _pdfViewerKey,
);
}
}
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Step 3: Update files with below code
import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:ndialog/ndialog.dart';
import 'package:syncfusion_flutter_pdfviewer/pdfviewer.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue, //primary theme color
),
home: FileDownload(), //call to homepage class
);
}
}
class FileDownload extends StatefulWidget{
@override
_FileDownloadState createState() => _FileDownloadState();
}
class _FileDownloadState extends State<FileDownload> {
late bool isLoading;
bool _allowWriteFile=false;
List<Course>courseContent= [];
String progress="";
late Dio dio;
@override
void initState() {
super.initState();
dio=Dio();
courseContent.add(Course(title:"Chapter 2",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap2.pdf"));
courseContent.add(Course(title:"Chapter 3",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap3.pdf"));
courseContent.add(Course(title:"Chapter 4",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap4.pdf"));
courseContent.add(Course(title:"Chapter 5",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap5.pdf"));
courseContent.add(Course(title:"Chapter 6",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap6.pdf"));
courseContent.add(Course(title:"Chapter 7A",path:"https://www.cs.purdue.edu/homes/ayg/CS251/slides/chap7a.pdf"));
}
requestWritePermission() async {
if (await Permission.storage.request().isGranted) {
setState(() {
_allowWriteFile = true;
});
}else
{
Map<Permission, PermissionStatus> statuses = await [
Permission.storage,
].request();
}
}
Future<String>getDirectoryPath() async
{
Directory appDocDirectory = await getApplicationDocumentsDirectory();
Directory directory= await new Directory(appDocDirectory.path+'/'+'dir').create(recursive: true);
return directory.path;
}
Future downloadFile(String url,path) async {
if(!_allowWriteFile)
{
requestWritePermission();
}
try{
ProgressDialog progressDialog=ProgressDialog(context,dialogTransitionType: DialogTransitionType.Bubble,title: Text("Downloading File"));
progressDialog.show();
await dio.download(url, path,onReceiveProgress: (rec,total){
setState(() {
isLoading=true;
progress=((rec/total)*100).toStringAsFixed(0)+"%";
progressDialog.setMessage(Text( "Dowloading $progress"));
});
});
progressDialog.dismiss();
}catch( e)
{
print(e.toString());
}
}
@override
Widget build(BuildContext context) {
// TODO: implement build
return Scaffold(
backgroundColor: Colors.white70,
appBar: AppBar(title: Text("FIle Download"),backgroundColor: Colors.red,),
body: Container(
child: ListView.builder(itemBuilder: (context,index){
String url =courseContent[index].path;
String title =courseContent[index].title;
String extension=url.substring(url.lastIndexOf("/"));
return Padding(
padding: const EdgeInsets.all(8.0),
child: Card(
elevation: 10,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Row(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Text("$title",style: TextStyle(fontSize: 26,color: Colors.purpleAccent,fontWeight: FontWeight.bold),),
RaisedButton(
color: Colors.green,
onPressed: (){
getDirectoryPath().then((path) {
File f=File(path+"$extension");
if(f.existsSync())
{
Navigator.push(context, MaterialPageRoute(builder: (context){
return PDFScreen(f.path);
}));
return;
}
downloadFile(url,"$path/$extension");
});
}, child: Text("View",style: TextStyle(fontSize: 16,color: Colors.white),),),
],
),
),
),
);
},itemCount: courseContent.length,),
),
);
}
}
class PDFScreen extends StatelessWidget {
String pathPDF = "";
PDFScreen(this.pathPDF);
final GlobalKey<SfPdfViewerState> _pdfViewerKey = GlobalKey();
@override
Widget build(BuildContext context) {
return SfPdfViewer.file(
File(pathPDF),
key: _pdfViewerKey,
);
}
}
class Course{
String title;
String path;
Course({required this.title,required this.path});
}
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