👀 Views: 35 💬 Answers: 1 📅 Created: 2025-06-17

android recyclerview livedata viewmodel kotlin

This might be a silly question, but I'm having a hard time understanding I'm experiencing a problem where a `TextView` inside a `RecyclerView` doesn't update its displayed text when the underlying data changes. I'm using Android's `ViewModel` architecture and observing a `LiveData` list of items, but it seems that when the data is updated, the `RecyclerView` does not reflect these changes unless I manually call `notifyDataSetChanged()` which feels inefficient. Here's how I set it up: In my `ViewModel`, I have a `LiveData<List<Item>>`: ```kotlin class MyViewModel : ViewModel() { private val _items = MutableLiveData<List<Item>>() val items: LiveData<List<Item>> get() = _items fun updateItems(newItems: List<Item>) { _items.value = newItems } } ``` In my `Activity`, I observe the `items` like this: ```kotlin viewModel.items.observe(this, Observer { newItems -> adapter.submitList(newItems) }) ``` My `RecyclerView` adapter looks like this: ```kotlin class MyAdapter : ListAdapter<Item, MyViewHolder>(ItemDiffCallback()) { override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder { val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false) return MyViewHolder(view) } override fun onBindViewHolder(holder: MyViewHolder, position: Int) { holder.bind(getItem(position)) } } ``` And the `ViewHolder` binds the data like this: ```kotlin class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) { private val textView: TextView = itemView.findViewById(R.id.text_view) fun bind(item: Item) { textView.text = item.name } } ``` Initially, everything works fine, but when I call `viewModel.updateItems(newList)` after modifying the list, the `TextView`s in the `RecyclerView` don’t update unless I manually refresh the adapter with `notifyDataSetChanged()`. I also tried using `submitList()` with `DiffUtil`, but that doesn't seem to trigger the update on the UI. I'm using AndroidX libraries and my `RecyclerView` is set up with `ListAdapter` which should handle updates efficiently. Any insights on why this behavior is happening? Is there a better approach to ensure the `TextView` updates without needing a full refresh? I'm targeting Android API level 21 and using Kotlin 1.5. Has anyone dealt with something similar? This is my first time working with Kotlin 3.9. Has anyone dealt with something similar? Any feedback is welcome!