Hilt ‐ About Hilt

`Contents`
`Hilt Basics`
`Hilt currently supports the following Android classes`
`Component lifetimes and scopes`
`Component Hierarchy`

`Hilt Basics`

Application class is mandatory for hilt, Based on the application class the application-wide singleton is created.
We use the annotation @HiltAndroidApp annotated to the application class.

The @AndroidEntryPoint indicates that the dependencies will be provided by Hilt to your component.
There can be more than one entry point.
For each entry point hilt tries to generate individual components. By doing so it tries to get rid of the dagger component that was needed earlier. As a result, developers don't have to write them making it easier for the developers.
If we annotate the fragment, we need to annotate the host activity as well.

Hilt is built on top of Dagger.
Hilt simplifies dagger-related infrastructure for Android applications.
Because Android OS instantiates many of its own framework classes, using a dagger in an Android app requires you to write a substantial amount of boilerplate code.
Hilt reduces the substantial amount of boilerplate code by automatically generating the components annotations and qualifiers
Hilt provides scope annotations out-of-the-box.
Hilt also provides pre-defined bindings for Activity and Application.
Hilt provides predefined qualifiers to represent @ApplicationContext and @ActivityContext.

`Android class`	`Generated Component`	`Scope`	`Created At`	`Destroyed At`	`Injected For`
`Application`	`SingletonComponent`	`@Singleton`	`Application#onCreate()`	`Application destroyed`	`Application`
`Activity`	`ActivityCompoment`	`@ActivityScoped`	`Activity#onCreate()`	`Activity#onDestroyed()`	`Activity`
`ViewModel`	`ViewModelComponent`	`@ViewModelScoped`	`ViewModel created`	`ViewModel destroyed`	`ViewModel`
`Fragment`	`FragmentComponent`	`@FragmentScoped`	`Fragment#onAttach()`	`Fragment#onDestroy()`	`Fragment`
`View`	`ViewCompoenet`	`@ViewScoped`	`View#super()`	`View destroyed`	`View`
`Service`	`ServiceComponent`	`@ServiceScoped`	`Service#onCreate()`	`Service#onDestroy()`	`Service`

hilt-hierarchy