Start Koin

Koin is a container & a pragamtic API to leverage your dependencies.

The Koin consists in:

  • KoinApplication: describe how to configure your Koin application
  • Module: describe your definitions

Starting Koin consists in using the startKoin fuction as below:

StartKoin

In a classical Dart file:

void main(){
startKoin((app){
// enable Printlogger with default Level.INFO
// can have Level & implementation
// equivalent to logger(Level.INFO, PrintLogger())
app.printLogger();
// list all used modules
app.module(coffeeAppModule);
});
}

Starting for Flutter

In any Flutter class:

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(myAppModules)
});
}
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage());
}
}

Custom Koin instance

Here below are the KoinApplication builders:

  • startKoin() - Create and register following KoinApplication instance
  • koinApplication() - create KoinApplication instance
// Create and register following KoinApplication instance
startKoin((app){
app.printLogger();
app.module(coffeeAppModule);
});
// create KoinApplication instance
koinApplication((app){
app.module(coffeeAppModule);
});

Logging

At start, Koin log what definition is bound by name or type (if log is activated):

[INFO] [Koin] bind type:'CoffeeMaker' ~ [type:Single,class:'CoffeeMaker']
[INFO] [Koin] bind type:'Pump' ~ [type:Single,class:'Pump']
[INFO] [Koin] bind type:'Heater' ~ [type:Single,class:'Heater']

DSL

A quick recap of the Koin keywords:

  • startKoin() - Create and register following KoinApplication instance
  • koinApplication() - create KoinApplication instance
  • modules(...) - declare used modules
  • logger() - declare PrintLogger
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