Scopes and Components¶

Table of Contents¶

Auto-detection (default)
Explicit component
Scope validation
Component and scope reference

Auto-detection (Default)¶

By default, @AutoBinds(installIn=...) is set to HiltComponent.Unspecified. The processor auto-detects the correct component from the scope annotation on the class. If the class has no scope annotation, SingletonComponent is used as the fallback.

// No scope annotation -> SingletonComponent
@AutoBinds
class UserRepository @Inject constructor() : UserDataSource {
    // ...
}

// @ActivityScoped -> ActivityComponent
@ActivityScoped
@AutoBinds
class SearchRepository @Inject constructor(
    private val api: SearchApi,
) : SearchDataSource {
    // ...
}

Explicit Component¶

You can set the component explicitly via the installIn parameter:

@AutoBinds(installIn = HiltComponent.ViewModel)
class SearchRepository @Inject constructor(
    private val api: SearchApi,
) : SearchDataSource {
    // ...
}

This works with both @AutoBinds and @AutoBindsIntoSet.

Scope Validation¶

When both a scope annotation and an explicit installIn are present, the processor validates that they match. A mismatch produces a compile error:

// ERROR: @Singleton does not match installIn = Activity
@Singleton
@AutoBinds(installIn = HiltComponent.Activity)
class RepoImpl @Inject constructor() : Repo

This prevents accidental misconfiguration where the scope and the component would contradict each other.

Component and Scope Reference¶

HiltComponent values¶

`HiltComponent` value	Dagger component
`Unspecified` (default)	auto-detected from scope
`Singleton`	`SingletonComponent`
`ActivityRetained`	`ActivityRetainedComponent`
`Activity`	`ActivityComponent`
`ViewModel`	`ViewModelComponent`
`Fragment`	`FragmentComponent`
`View`	`ViewComponent`
`ViewWithFragment`	`ViewWithFragmentComponent`
`Service`	`ServiceComponent`

Scope auto-detection mapping¶

Scope annotation	Resolved component
`@Singleton`	`SingletonComponent`
`@ActivityRetainedScoped`	`ActivityRetainedComponent`
`@ActivityScoped`	`ActivityComponent`
`@ViewModelScoped`	`ViewModelComponent`
`@FragmentScoped`	`FragmentComponent`
`@ViewScoped`	`ViewComponent`
`@ServiceScoped`	`ServiceComponent`
(none)	`SingletonComponent`

Note

@ViewScoped maps to ViewComponent by default, not ViewWithFragmentComponent. Use installIn = HiltComponent.ViewWithFragment explicitly if needed.