import 'dart:async';
import 'dart:io';
import 'dart:isolate';
import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter_downloader/flutter_downloader.dart';
import 'package:path_provider/path_provider.dart';
import 'package:permission_handler/permission_handler.dart';
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await FlutterDownloader.initialize();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
final platform = Theme.of(context).platform;
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(
title: 'Downloader',
platform: platform,
),
);
}
}
class MyHomePage extends StatefulWidget with WidgetsBindingObserver {
final TargetPlatform platform;
MyHomePage({Key key, this.title, this.platform}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final _documents = [
{
'name': 'Learning Android Studio',
'link':
'http://barbra-coco.dyndns.org/student/learning_android_studio.pdf'
},
{
'name': 'Android Programming Cookbook',
'link':
'http://enos.itcollege.ee/~jpoial/allalaadimised/reading/Android-Programming-Cookbook.pdf'
},
];
List<_TaskInfo> _tasks;
List<_ItemHolder> _items;
bool _isLoading;
bool _permissionReady;
String _localPath;
ReceivePort _port = ReceivePort();
@override
void initState() {
super.initState();
_bindBackgroundIsolate();
FlutterDownloader.registerCallback(downloadCallback);
_isLoading = true;
_permissionReady = false;
_prepare();
}
@override
void dispose() {
_unbindBackgroundIsolate();
super.dispose();
}
void _bindBackgroundIsolate() {
bool isSuccess = IsolateNameServer.registerPortWithName(
_port.sendPort, 'downloader_send_port');
if (!isSuccess) {
_unbindBackgroundIsolate();
_bindBackgroundIsolate();
return;
}
_port.listen((dynamic data) {
print('UI Isolate Callback: $data');
String id = data[0] as String;
DownloadTaskStatus status = data[1] as DownloadTaskStatus;
int progress = data[2] as int;
final task = _tasks?.firstWhere((task) => task.taskId == id);
if (task != null) {
setState(() {
task.status = status;
task.progress = progress;
});
}
});
}
void _unbindBackgroundIsolate() {
IsolateNameServer.removePortNameMapping('downloader_send_port');
}
static void downloadCallback(
String id, DownloadTaskStatus status, int progress) {
print(
'Background Isolate Callback: task ($id) is in status ($status) and process ($progress)');
final SendPort send =
IsolateNameServer.lookupPortByName('downloader_send_port');
send.send([id, status, progress]);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Builder(
//builderの意味分かってない
builder: (context) => _isLoading
? Center(
child: CircularProgressIndicator(),
)
: _permissionReady
? Container(
child: ListView(
padding: const EdgeInsets.symmetric(vertical: 16.0),
children: _items
.map((item) => item.task == null
? Container(
padding: const EdgeInsets.symmetric(
horizontal: 16.0, vertical: 8.0),
child: Text(
item.name,
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.blue,
fontSize: 18.0),
),
)
: Container(
padding: const EdgeInsets.only(
left: 16.0, right: 8.0),
child: InkWell(
onTap: item.task.status ==
DownloadTaskStatus.complete
? () {
_openDownloadedFile(item.task)
.then((success) {
if (!success) {
Scaffold.of(context)
.showSnackBar(SnackBar(
content: Text(
'Cannot open this file')));
}
});
}
: null,
child: Stack(
children: <Widget>[
Container(
width: double.infinity,
height: 64.0,
child: Row(
crossAxisAlignment:
CrossAxisAlignment.center,
children: <Widget>[
Expanded(
child: Text(
item.name,
maxLines: 1,
softWrap: true,
overflow:
TextOverflow.ellipsis,
),
),
Padding(
padding:
const EdgeInsets.only(
left: 8.0),
child: _buildActionForTask(
item.task),
),
],
),
),
item.task.status ==
DownloadTaskStatus
.running ||
item.task.status ==
DownloadTaskStatus.paused
? Positioned(
left: 0.0,
right: 0.0,
bottom: 0.0,
child:
LinearProgressIndicator(
value: item.task.progress /
100,
),
)
: Container()
]
.where((child) => child != null)
.toList(),
),
),
))
.toList(),
),
)
: Container(
child: Center(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Padding(
padding:
const EdgeInsets.symmetric(horizontal: 24.0),
child: Text(
'Please grant accessing storage permission to continue -_-',
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.blueGrey, fontSize: 18.0),
),
),
SizedBox(
height: 32.0,
),
FlatButton(
onPressed: () {
_checkPermission().then((hasGranted) {
setState(() {
_permissionReady = hasGranted;
});
});
},
child: Text(
'Retry',
style: TextStyle(
color: Colors.blue,
fontWeight: FontWeight.bold,
fontSize: 20.0),
))
],
),
),
)),
);
}
Widget _buildActionForTask(_TaskInfo task) {
if (task.status == DownloadTaskStatus.undefined) {
return RawMaterialButton(
onPressed: () {
_requestDownload(task);
},
child: Icon(Icons.file_download),
shape: CircleBorder(),
constraints: BoxConstraints(minHeight: 32.0, minWidth: 32.0),
);
} else if (task.status == DownloadTaskStatus.running) {
return RawMaterialButton(
onPressed: () {
_pauseDownload(task);
},
child: Icon(
Icons.pause,
color: Colors.red,
),
shape: CircleBorder(),
constraints: BoxConstraints(minHeight: 32.0, minWidth: 32.0),
);
} else if (task.status == DownloadTaskStatus.paused) {
return RawMaterialButton(
onPressed: () {
_resumeDownload(task);
},
child: Icon(
Icons.play_arrow,
color: Colors.green,
),
shape: CircleBorder(),
constraints: BoxConstraints(minHeight: 32.0, minWidth: 32.0),
);
} else if (task.status == DownloadTaskStatus.complete) {
return Row(
mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.end,
children: [
Text(
'Ready',
style: TextStyle(color: Colors.green),
),
RawMaterialButton(
onPressed: () {
_delete(task);
},
child: Icon(
Icons.delete_forever,
color: Colors.red,
),
shape: CircleBorder(),
constraints: BoxConstraints(minHeight: 32.0, minWidth: 32.0),
)
],
);
} else if (task.status == DownloadTaskStatus.canceled) {
return Text('Canceled', style: TextStyle(color: Colors.red));
} else if (task.status == DownloadTaskStatus.failed) {
return Row(
mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.end,
children: [
Text('Failed', style: TextStyle(color: Colors.red)),
RawMaterialButton(
onPressed: () {
_retryDownload(task);
},
child: Icon(
Icons.refresh,
color: Colors.green,
),
shape: const CircleBorder(),
constraints: const BoxConstraints(minHeight: 32, minWidth: 32),
)
],
);
} else {
return null;
}
}
void _requestDownload(_TaskInfo task) async {
task.taskId = await FlutterDownloader.enqueue(
url: task.link,
headers: {"auth": "test_for_sql_encoding"},
savedDir: _localPath,
showNotification: true,
openFileFromNotification: true);
}
void _cancelDownload(_TaskInfo task) async {
await FlutterDownloader.cancel(taskId: task.taskId);
}
void _pauseDownload(_TaskInfo task) async {
await FlutterDownloader.pause(taskId: task.taskId);
}
void _resumeDownload(_TaskInfo task) async {
String TaskId = await FlutterDownloader.resume(taskId: task.taskId);
task.taskId = TaskId;
}
void _retryDownload(_TaskInfo task) async {
String TaskId = await FlutterDownloader.retry(taskId: task.taskId);
task.taskId = TaskId;
}
Future<bool> _openDownloadedFile(_TaskInfo task) {
return FlutterDownloader.open(taskId: task.taskId);
}
void _delete(_TaskInfo task) async {
await FlutterDownloader.remove(
taskId: task.taskId, shouldDeleteContent: true);
await _prepare();
setState(() {});
}
Future<bool> _checkPermission() async {
if (widget.platform == TargetPlatform.android) {
PermissionStatus permission = await PermissionHandler()
.checkPermissionStatus(PermissionGroup.storage);
if (permission != PermissionStatus.granted) {
Map<PermissionGroup, PermissionStatus> permissions =
await PermissionHandler()
.requestPermissions([PermissionGroup.storage]);
if (permissions[PermissionGroup.storage] == PermissionStatus.granted) {
return true;
}
} else {
return true;
}
} else {
return true;
}
return false;
}
Future<Null> _prepare() async {
final tasks = await FlutterDownloader.loadTasks();
int count = 0;
_tasks = [];
_items = [];
_tasks.addAll(_documents.map((document) =>
_TaskInfo(name: document['name'], link: document['link'])));
_items.add(_ItemHolder(name: 'Documents'));
for (int i = count; i < _tasks.length; i++) {
_items.add(_ItemHolder(name: _tasks[i].name, task: _tasks[i]));
count++;
}
/*
_tasks.addAll(_images
.map((image) => _TaskInfo(name: image['name'], link: image['link'])));
_items.add(_ItemHolder(name: 'Images'));
for (int i = count; i < _tasks.length; i++) {
_items.add(_ItemHolder(name: _tasks[i].name, task: _tasks[i]));
count++;
}
_tasks.addAll(_videos
.map((video) => _TaskInfo(name: video['name'], link: video['link'])));
_items.add(_ItemHolder(name: 'Videos'));
for (int i = count; i < _tasks.length; i++) {
_items.add(_ItemHolder(name: _tasks[i].name, task: _tasks[i]));
count++;
}
*/
tasks?.forEach((task) {
for (_TaskInfo info in _tasks) {
if (info.link == task.url) {
info.taskId = task.taskId;
info.status = task.status;
info.progress = task.progress;
}
}
});
_permissionReady = await _checkPermission();
_localPath = (await _findLocalPath()) + Platform.pathSeparator + 'Download';
final savedDir = Directory(_localPath);
bool hasExisted = await savedDir.exists();
if (!hasExisted) {
savedDir.create();
}
setState(() {
_isLoading = false;
});
}
Future<String> _findLocalPath() async {
final directory = widget.platform == TargetPlatform.android
? await getExternalStorageDirectory()
: await getApplicationDocumentsDirectory();
return directory.path;
}
}
class _TaskInfo {
final String name;
final String link;
String taskId;
int progress = 0;
DownloadTaskStatus status = DownloadTaskStatus.undefined;
_TaskInfo({this.name, this.link});
}
class _ItemHolder {
final String name;
final _TaskInfo task;
_ItemHolder({this.name, this.task});
}