How to get a result from fragment using Navigation Architecture Component?

Question

Let\'s say that we have two fragments: MainFragment and SelectionFragment. The second one is build for selecting some object, e.g. an integer. Ther

Answer 1

Use these extension functions

fun  Fragment.getNavigationResult(key: String = "result") =
    findNavController().currentBackStackEntry?.savedStateHandle?.get(key)

fun  Fragment.getNavigationResultLiveData(key: String = "result") =
        findNavController().currentBackStackEntry?.savedStateHandle?.getLiveData(key)

fun  Fragment.setNavigationResult(result: T, key: String = "result") {
    findNavController().previousBackStackEntry?.savedStateHandle?.set(key, result)
}

So if you want to send result from Fragment B to fragment A

Inside Fragment B

setNavigationResult(false, "someKey")

Inside Fragment A

val result = fragment.getNavigationResultLiveData("someKey")
result.observe(viewLifecycleOwner){ booleanValue-> doSomething(booleanValue)