Getting Started with Flutter application

This tutorial lets you write an Flutter/Dart application and use Koin inject and retrieve your components.

Setup

Add the Koin Flutter dependency like below:

Package	Pub
koin
koin_flutter

dependencies:

koin: ^[laste_version]

koin_flutter: ^[laste_version]

Our components

Let's create a HelloRepository to provide some data:

class HelloRepository {

giveHello() => "Hello Koin";

}

Let's create business logic class, for consuming this data:

class MyBloc {

final HelloRepository helloRepository;

MyBloc(this.helloRepository);

}

Writing the Koin module

Use the module function to declare a module. Let's declare our first component:

// just declare it

final myModule = Module()

..single((s) => HelloRepository())

..factory((s) => MyBloc(s.get()));

?> we declare our MyBloc class as factory to have a create a new instance each time our Widget will need one.

Start Koin

Now that we have a module, let's start it with Koin. Open your application class. Just call the startKoin() function:

class MyApp extends StatefulWidget {

@override

_MyAppState createState() => _MyAppState();

}

class _MyAppState extends State<MyApp> {

@override

void initState() {

super.initState();

startKoin((app) {

app.printLogger(level: Level.debug);

app.modules(myModule)

});

}

@override

Widget build(BuildContext context) {

return MaterialApp(

title: 'Flutter Demo',

theme: ThemeData(

primarySwatch: Colors.blue,

),

home: MyHomePage());

}

}

Injecting dependencies

The MyBloc component will be created with HelloRepository instance. To get it into our Widget, let's inject it with the by get() delegate injector:

class MyHomePage extends StatelessWidget {

@override

Widget build(BuildContext context) {

// Get a dependency

var controller = get<MyBloc>();

return Container(

child: Text("${controller.toString()}"),

);

}

}

The by inject() function allows us to retrieve lazy Koin instances The get() function is here to retrieve directly an instance (non lazy)