How to use variables on different class with dart/flutter - dart

Question

I have one class which is my getToken class. In this class ı get the token which is String token. Here is my getToken.dart
class GetToken {
String token;
Future<Null> getData() async {
var url = "http://192.168.1.39:7070/api/v2/token";
http.post(url, body: {
"grant_type": "string",
"branchcode": "string",
"password": "string",
"username": "string",
"dbname": "string",
"dbuser": "string",
"dbpassword": "string",
"dbtype": "string"
}).then((response) {
print("Response Status: ${response.statusCode}");
//print("Response Body: ${response.body}");
print('access token is -> ${json.decode(response.body)['access_token']}');
token = json.decode(response.body)['access_token'];
});
}
}
I want to use this token in my getCari class and get the Json values in my rest api. Here is my getCari.dart class
class GetCari{
getCari() async {
final response = await http.get("http://192.168.1.39:7070/api/v2/ARPs",
headers: {HttpHeaders.AUTHORIZATION: token});
if(response.statusCode ==200){
return Cari.fromJson(json.decode(response.body));
}else{
throw Exception("Failed to Load");
}
}
}
I would like to ask how can ı use my token(which is get from getToken.dart) in my getCari.dart class. How can ı pass the token variable other classes?

Answer 1

Please use Dart's top level functions instead of classes which does not need instantiation.
This is mentioned in Effective Dart documentation
token_manager.dart
String _token;
String get token => _token // To ensure readonly
Future<Null> setToken() async {
// set your _token here
}
get_cari.dart
import 'token_manager.dart' as token_manager // use your import path here
getCari() async {
// You can now access token from token_manager from any class like this.
final String token = token_manager.token;
}
Excerpt
In Java and C#, every definition must be inside a class, so it’s
common to see “classes” that exist only as a place to stuff static
members. Other classes are used as namespaces—a way to give a shared
prefix to a bunch of members to relate them to each other or avoid a
name collision.
Dart has top-level functions, variables, and constants, so you don’t
need a class just to define something. If what you want is a
namespace, a library is a better fit. Libraries support import
prefixes and show/hide combinators. Those are powerful tools that let
the consumer of your code handle name collisions in the way that works
best for them.
If a function or variable isn’t logically tied to a class, put it at
the top level. If you’re worried about name collisions, give it a more
precise name or move it to a separate library that can be imported
with a prefix.

Answer 2

you can pass data to getCari method by create object fromGetCari() class
see this
class GetToken {
String token;
Future<Null> getData() async {
var url = "http://192.168.1.39:7070/api/v2/token";
http.post(url, body: {
"grant_type": "string",
"branchcode": "string",
"password": "string",
"username": "string",
"dbname": "string",
"dbuser": "string",
"dbpassword": "string",
"dbtype": "string"
}).then((response) {
print("Response Status: ${response.statusCode}");
//print("Response Body: ${response.body}");
print('access token is -> ${json.decode(response.body)['access_token']}');
token = json.decode(response.body)['access_token'];
GetCari().getCari("fdfd");
});
}
}
class GetCari{
getCari(String token) async {
final response = await http.get("http://192.168.1.39:7070/api/v2/ARPs",
headers: {HttpHeaders.AUTHORIZATION: token});
if(response.statusCode ==200){
return Cari.fromJson(json.decode(response.body));
}else{
throw Exception("Failed to Load");
}
}

Answer 3

You can use a service manager like get_it to reuse values anywhere in your app.
Create the class that will hold your shared information
class GetToken{
String token;
...
}
In your main.dart file, setup your GetIt instance
final getIt = GetIt.instance;
void setup() {
getIt.registerSingleton<GetToken>(GetToken());
}
Now, from anywhere in your app, you can call this class and get your token.
var mytoken= getIt.get<AppModel>().token;