Global configuration (interceptor) for dio in Flutter - flutter

Question

First time with Flutter. I'm using dio to send HTTP requests, and I have to add a header to all requests, which I do with an interceptor, like this:
Dio dio = new Dio();
dio.interceptors.add(InterceptorsWrapper(
onRequest:(RequestOptions options) async {
options.headers["X-Requested-With"] = "XMLHttpRequest";
})
);
It works in main.dart, but if I want to import another class like MyHomePage.dart and do HTTP requests there, I'd have to redefine the interceptor in that class too.
How can I implement this interceptor for my whole application without adding it in every .dart file?

Answer 1

Create a function that houses the DIO and then call it where needed
Dio getDio() {
Dio dio = new Dio();
dio.interceptors.add(InterceptorsWrapper(onRequest: (RequestOptions options) async {
options.headers["X-Requested-With"] = "XMLHttpRequest";
}));
return dio;
}

Answer 2

This worked good for me, without interceptors, just create a class and use it in your app.
import 'package:dio/dio.dart';
import '../helpers/api_url.dart';
class dioClient {
Dio dio = Dio();
static Dio simpleDio() {
return Dio(BaseOptions(
baseUrl: apiUrl(),
headers: {'Content-Type': 'application/json; charset=UTF-8'}));
}
static Dio dioWithCookie(String cookie) {
return Dio(BaseOptions(baseUrl: apiUrl(), headers: {
'Content-Type': 'application/json; charset=UTF-8',
'Cookie': cookie
}));
}
}