如何在应用程序中跨多个片段共享数据？

Question

I am working on an application where im taking input from users across multiple fragments under same activity, and then i am sending that data to firebase now how can i achieve that using shared viewmodel, if possible please guide me how can i achieve that, I am completely new to android. Thank You

Answer 1

Can you please elaborate and share some code? It is very difficult to understand what your question is.

Answer 2

I'm assuming you want to share data between fragments. One way to do that is through ViewModels

Specifically, you'll need a view model like this:

class SharedViewModel : ViewModel() {
    val selected = MutableLiveData<Item>()

    fun select(item: Item) {
        selected.value = item
    }
}

Then you have your fragments:

class SharedViewModel : ViewModel() {
    val selected = MutableLiveData<Item>()

    fun select(item: Item) {
        selected.value = item
    }
}

class ListFragment : Fragment() {

    private lateinit var itemSelector: Selector

    private val model: SharedViewModel by activityViewModels()

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        itemSelector.setOnClickListener { item ->
            // Update the UI
        }
    }
}

class DetailFragment : Fragment() {

    private val model: SharedViewModel by activityViewModels()

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        model.selected.observe(viewLifecycleOwner, Observer<Item> { item ->
            // Update the UI
        })
    }
}

Notice that both fragments retrieve the activity that contains them. That way, when the fragments each get the ViewModelProvider, they receive the same SharedViewModel instance, which is scoped to this activity.

If you want to know more about this, refer to: https://developer.android.com/topic/libraries/architecture/viewmodel