How to handle "Lost connection to device." error - flutter

Question

I created an app, which contains login and dashboard screen, i used Nodejs backend and mongodb also. i trying to add functionality when user logged in and close the app without logging out and then when user come to the app it should display where it left last time. so i used shared preference for it. I am testing it now, when i logged in and close the app using the right-most button (which shows all the currently running apps) it send me this "Lost connection to device.
".
login Code:
bool newuser;
String type ;
SharedPreferences myPrefs;
void initState() {
checkIfLoggedinalready();
}
Future login() async {
try {
Dio dio = new Dio();
var data = {
'username':"Munib khatri",
'password': "Munib123",
'date': "5/5/2021"
};
await dio
.post(localhostUrlLogin, data: json.encode(data))
.then((onResponse) async {
type = onResponse.data['User']['Type'];
if (type == 'Employee') {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Employee()));
} else if (type == 'Manager') {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Manager()));
}
myPrefs.setBool('login', false);
});
} catch (e) {
}
}
void checkIfLoggedinalready() async{
myPrefs = await SharedPreferences.getInstance();
newuser = (myPrefs.getBool('login') ?? true);
print(newuser);
if (newuser == false && type == 'Employee') {
Navigator.pushReplacement(
context, new MaterialPageRoute(builder: (context) => Employee()));
}
}
dashboard code:
i am doing this on drawer code where i use logout
new ListTile(
title: new Text('Log out'),
leading: Icon(Icons.logout,color:Colors.grey),
onTap: (){
myPrefs.setBool('login', true); //here i set it to true, if user is new
Navigator.pop(context);
Navigator.push(context, new MaterialPageRoute(
builder: (context)=>
Login()
)
);
},
),
please help it would be appreciated.

Answer 1

Lost connection to device is not a coding issue, your linked device got disconnected at that time due to data cable, If you will test this on emulator then you will not get this issue.
If you are saving user data on Shared preference then do encode your sensitive data before saving it.

Answer 2

var response =
await http.post(Uri.parse(parseUse), body: json.encode(data), headers: { "Content-Type": "application/json; charset=UTF-8", }).timeout(Duration(minutes: 2));
Updated Answer :
try{
Dio dio = new Dio();
var data = {
'username':"Munib khatri",
'password': "Munib123",
'date': "5/5/2021"
};
await dio
.post(localhostUrlLogin, data: json.encode(data))
.then((onResponse) async {
type = onResponse.data['User']['Type'];
if (type == 'Employee') {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Employee()));
} else if (type == 'Manager') {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Manager()));
}
myPrefs.setBool('login', false);
});
}on DioError catch (e){
if(e.type == DioErrorType.connectTimeout){
"You can put a alert dialog or something you prefer".
}
}
or you can also use base Option since your using DIO
var dio = Dio(); // with default Options
// Set default configs
dio.options.baseUrl = 'https://www.xx.com/api';
dio.options.connectTimeout = 5000; //5s
dio.options.receiveTimeout = 3000;
// or new Dio with a BaseOptions instance.
var options = BaseOptions(
baseUrl: 'https://www.xx.com/api',
connectTimeout: 5000,
receiveTimeout: 3000,
);
Dio dio = Dio(options);
response = await dio.request(
'/test',
data: {'id':12,'name':'xx'},
options: Options(method:'GET'),
);