I have a RecyclerView in MVVM project. I have to get text from editText (searchWordEt) and then pass it to the function that invokes API method in viewmodel.API works fine and returns data. But when I invoke searchDefAdapter.submitList(response) in SearchFragment nothing happens and RecyclerView data not showing.

class SearchDefAdapter(
    private var infoListener: OnItemClickListener,
    private var addListener: OnItemClickListener
):
    ListAdapter<Def, SearchDefViewHolder>(differCallback) {
    interface OnItemClickListener {
        fun onItemClick(position: Int)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SearchDefViewHolder {
        return SearchDefViewHolder(
            SearchWordCardBinding.inflate(
                LayoutInflater.from(parent.context),
                parent,
                false
            ),
            addListener,
            infoListener
        )
    }

    override fun onBindViewHolder(holder: SearchDefViewHolder, position: Int) {
        holder.bind(getItem(position))
    }
}

class SearchDefViewHolder(
    private val binding: SearchWordCardBinding,
    addListener: SearchDefAdapter.OnItemClickListener,
    infoListener: SearchDefAdapter.OnItemClickListener
): RecyclerView.ViewHolder(binding.root) {
    fun bind(data: Def) {
        with (binding) {
            searchCardTv.text = "${data.text} - ${data.tr[0].text}"
        }
    }

    init {
        binding.addSearchCard.setOnClickListener {
            addListener.onItemClick(adapterPosition)
        }

        binding.infoSearchCard.setOnClickListener {
            infoListener.onItemClick(adapterPosition)
        }
    }
}

val differCallback = object : DiffUtil.ItemCallback<Def>() {
    override fun areItemsTheSame(oldItem: Def, newItem: Def): Boolean {
        return oldItem.text == newItem.text
    }

    override fun areContentsTheSame(oldItem: Def, newItem: Def): Boolean {
        return oldItem == newItem
    }
}

@AndroidEntryPoint
class SearchFragment : Fragment() {
    private var _binding: FragmentSearchBinding? = null
    private val binding get() = _binding!!

    lateinit var searchDefAdapter: SearchDefAdapter
    private val viewModel: DictionaryViewModel by activityViewModels()

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        _binding = FragmentSearchBinding.inflate(inflater, container, false)
        val view = binding.root

        searchDefAdapter = SearchDefAdapter(
            object : SearchDefAdapter.OnItemClickListener {
                override fun onItemClick(position: Int) {
                    Log.d("tag", "Item Added!")
                    //viewModel.saveWord(position)
                }
            },
            object : SearchDefAdapter.OnItemClickListener {
                override fun onItemClick(position: Int) {
                    val wordFragment = WordFragment()
                    fragmentManager?.beginTransaction()?.replace(
                        R.id.nav_host_fragment_container,
                        wordFragment
                    )?.commit()
                }
            }
        )

        setUpRecyclerView(searchDefAdapter)

        var job: Job? = null
        binding.searchWordEt.addTextChangedListener { editable ->
            job?.cancel()
            job = MainScope().launch {
                delay(SEARCH_WORD_TIME_DELAY)
                editable?.let {
                    if (editable.toString().isNotEmpty())
                        viewModel.getTranslation(editable.toString())
                }
            }
        }

        viewModel.def.observe(viewLifecycleOwner, Observer { response ->
            binding.apply {
                searchDefAdapter.submitList(response)
            }
        })

        return view
    }

    override fun onDestroyView() {
        _binding = null
        super.onDestroyView()
    }

    private fun setUpRecyclerView(adapter: SearchDefAdapter){
        binding.searchRv.apply {
            adapter
            layoutManager = LinearLayoutManager(activity)
        }
    }
}

CodePudding user response：

You haven't actually set the adapter in setUpRecyclerView()

private fun setUpRecyclerView(myAdapter: SearchDefAdapter){
        binding.searchRv.apply {
            layoutManager = LinearLayoutManager(activity)
            adapter = myAdapter // here
        }
    }