How to databind to onTextChanged for an EditText on Android?

Question

In Yigit Boyar and George Mount\'s talk on Android Databinding they illustrate how easy it is to bind to TextWatcher\'s onTextChanged (at 13:41). O

Answer 1

I got it working like this:

Fragment:

    class DiAtomicMoleculesFragment : Fragment() {
        private lateinit var binding: FragmentDiatomicMoleculesBinding

        override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
        ): View? {
            binding = FragmentDiatomicMoleculesBinding.inflate(layoutInflater, container, false)
            return binding.root
        }

        override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
            super.onViewCreated(view, savedInstanceState)
            val recyclerAdapter = DiAtomicMoleculesAdapter(onClickListener)

            binding.diRecyclerView.apply {
                setHasFixedSize(true)
                layoutManager = LinearLayoutManager(activity, LinearLayoutManager.VERTICAL, false)
                adapter = recyclerAdapter
            }

            val viewModel = ViewModelProvider(this).get(DiAtomicMoleculesViewModel::class.java)
            viewModel.getDiAtomicMolecules().observe(viewLifecycleOwner, Observer { items ->
                recyclerAdapter.setData(items)
            })

            viewModel.getDiAtomicMoleculesByName().observe(viewLifecycleOwner, Observer { items ->
                recyclerAdapter.setData(items)
            })

            //this is important
            binding.viewModel = viewModel
        }
    }

layout.xml:

ViewModel:

class DiAtomicMoleculesViewModel : ViewModel() {
    private val allLiveData = AppDatabase.getInstance().getDiAtomicMoleculeDao().getAll()
    private val filterLiveData = MutableLiveData()
    private val searchByLiveData = Transformations.switchMap(filterLiveData, ::filter)

    fun getDiAtomicMolecules(): LiveData> {
        return allLiveData
    }

    private fun filter(text: String): LiveData> {
        return AppDatabase.getInstance().getDiAtomicMoleculeDao().find(text)
    }

    fun getDiAtomicMoleculesByName(): LiveData> {
        return searchByLiveData
    }

    fun onTextChange(e: Editable?) {
        filterLiveData.value = e?.toString()
    }

    fun onTextChange(text: CharSequence?) {
        filterLiveData.value = text?.toString()
    }
}