Dagger Assisted Injection example Android

readme.md

Example usage of dagger assist annotation

For more information visit documentation:

https://dagger.dev/dev-guide/assisted-injection.html

MenuItemSearchBehavior.kt

class MenuItemSearchBehavior
@AssistedInject internal constructor(
    @Assisted private val hint: String,
    @Assisted private val activityProvider: () -> Activity,
    @Assisted onMenuCreated: ((menu: Menu) -> Unit)?,
    analytics: IMenuAnalytics
) : MenuBehavior(
    menuRes = R.menu.menu_search,
    R.id.action_search to { item -> analytics.trackMenuItemClicked(item) },
    onMenuCreated = onMenuCreated
) {

....    

    @AssistedFactory
    internal interface InternalFactory {
        fun create(
            activityProvider: () -> Activity,
            hint: String,
            onMenuCreated: ((menu: Menu) -> Unit)? = null,
        ): MenuItemSearchBehavior
    }

    class Factory @Inject internal constructor(private val internal: InternalFactory) {
        fun create(
            activity: Activity,
            hint: String,
            onMenuCreated: ((menu: Menu) -> Unit)? = null,
        ) = internal.create(
            activityProvider = { activity },
            hint = hint,
            onMenuCreated = onMenuCreated
        )

        fun create(
            fragment: Fragment,
            hint: String,
            onMenuCreated: ((menu: Menu) -> Unit)? = null,
        ) = internal.create(
            activityProvider = { fragment.requireActivity() },
            hint = hint,
            onMenuCreated = onMenuCreated
        )
    }
}

ProductsFragment.kt

ProductsFragment {
    @Inject
    lateinit var menuBehaviorFactory: MenuItemSearchBehavior.Factory
...

    init {
        InjectorProvider.requireAccountComponent().inject(this)
        val hint = translateFromKey(com.cmcmarkets.translations.R.string.key_search_products)
        addBehavior(
            menuBehaviorFactory.create(
                fragment = this,
                hint = hint,
            )
        )
    }
...
}