当按钮添加新下载时，如何为每个下载提供唯一 ID？我正在使用 Flutter_Downloader api
由于静态方法用于隔离的通信，我尝试将 is id 引用到类，但无济于事。帮助代码如下
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<String> saveList = [];
bool isdown = false;
ReceivePort _port = ReceivePort();
int progress = 0;
String id;
DownloadTaskStatus status;
int progresscomplite = 100;
@override
void initState() {
super.initState();
_downloadListener();
}
@override
void dispose() {
disp();
super.dispose();
}
void disp() {
IsolateNameServer.removePortNameMapping('downloader');
}
static void downloadCallback(
String id, DownloadTaskStatus status, int progress) {
final SendPort send = IsolateNameServer.lookupPortByName('downloader' );
send.send([id, status, progress]);
}
_downloadListener() {
bool isSuccess =
IsolateNameServer.registerPortWithName(_port.sendPort, 'downloader');
if (!isSuccess) {
disp();
_downloadListener();
return;
}
IsolateNameServer.registerPortWithName(_port.sendPort, 'downloader');
_port.listen((dynamic data) {
setState(() {
isdown = true;
id = data[0];
status = data[1];
progress = data[2];
});
print('$progress');
});
FlutterDownloader.registerCallback(downloadCallback);
}
void _download() async {
String _localPath =
(await findLocalPath()) + Platform.pathSeparator + 'Example_Downloads';
final savedDir = Directory(_localPath);
bool hasExisted = await savedDir.exists();
if (!hasExisted) {
savedDir.create();
}
String _url =
"https://upload.wikimedia.org/wikipedia/commons/e/e4/GatesofArctic.jpg";
final download = await FlutterDownloader.enqueue(
url: _url,
savedDir: _localPath,
showNotification: true,
openFileFromNotification: true,
);
}
Future<String> findLocalPath() async {
final directory =
// (MyGlobals.platform == "android")
// ?
await getExternalStorageDirectory();
// : await getApplicationDocumentsDirectory();
return directory.path;
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: isdown
? Column(
children: [
Center(
child: LinearProgressIndicator(
value: progress / 100,
minHeight: 10,
),
),
MaterialButton(
onPressed: () async {
await FlutterDownloader.pause(taskId: id);
},
child: Text('pause'),
),
MaterialButton(
onPressed: () async {
await FlutterDownloader.resume(taskId: id);
},
child: Text('resume'),
)
],
)
: Text('no data'),
floatingActionButton: FloatingActionButton(
onPressed: _download,
child: Icon(Icons.file_download),
),
);
}
}
class SecondTab extends StatefulWidget {
SecondTab({Key key}) : super(key: key);
@override
_SecondTabState createState() => _SecondTabState();
}
class _SecondTabState extends State<SecondTab> {
var files;
// ShareModel share;
// _SecondTabState({this.share});
void getFiles() async {
//asyn function to get list of files
//List<StorageInfo> storageInfo = await PathProviderEx.getStorageInfo();
//var root = storageInfo[0].rootDir; //storageInfo[1] for SD card, geting the root directory
var fm = FileManager(root: Directory('/storage/emulated/0/VideoTube')); //
files = await fm.filesTree(
// fm.dirsTree() for directory/folder tree list
excludedPaths: ["/storage/emulated/0/VideoTube/"],
extensions: ["mp4"] //optional, to filter files, remove to list all,
// remove this if your are grabbing folder list
);
setState(() {}); //update the UI
}
@override
void initState() {
getFiles(); //call getFiles() function on initial state.
super.initState();
}
@override
Widget build(BuildContext context) {
// super.build(context);
return Scaffold(
appBar: AppBar(
title: Text("File/Folder list from SD Card"),
backgroundColor: Colors.redAccent),
body: Column(children: <Widget>[
FutureBuilder(
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
return Flexible(
flex: 9,
child: Container(
child: files == null
? Text("Searching Files")
: ListView.builder(
//if file/folder list is grabbed, then show here
itemCount: files?.length ?? 0,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(files[index].path.split('/').last),
leading: Icon(Icons.video_label),
trailing: Icon(
Icons.delete,
color: Colors.redAccent,
),
));
},
),
),
);
},
),
]));
}
}
当应用程序关闭时我们将如何保持下载以便能够恢复下载