LiveData Event Mediator Beta

EventMediator.kt

interface EventMediator<T> {
    interface Input<T> {
        fun bind(input: LiveData<T>)
    }

    interface Output<T> {
        val onAction: LiveData<T>
    }
    
    val input: Input<T>
    val output: Output<T>
    companion object {
        fun <T> create() = object : EventMediator<T> {
            override val output = object : Output<T> {
                override val onAction: MediatorLiveData<T> = MediatorLiveData()
            }
            override val input = object : Input<T> {
                override fun bind(input: LiveData<T>) {
                    output.onAction.addSource(input) {
                        output.onAction.value = it
                    }
                }
            }
        }
    }
}

class FooListViewModel {
    private val eventMediator = FooListEventMediator()
    val listItemClick: EventMediator<FooListItem>
        get() = eventMediator.listItemClick
}
class FooListEventMediator {
    val listItemClick: EventMediator<FooListItem> = EventMediator.create()
}

適当につくったけど、これでは単にMediatorLiveDataの方が良さそうに見える

This is better than custom something.

    val listItemClickEventInput = MediatorLiveData<FooListItem>()
    val listItemClickEventOutput: LiveData<FooListItem>
        get() = listItemClickEventInput