👀 Views: 342 💬 Answers: 1 📅 Created: 2025-06-17

android recyclerview constraintlayout kotlin

I'm having a hard time understanding I'm experiencing significant UI lag when scrolling through a nested RecyclerView structure within a ConstraintLayout in my Android app targeting API 34. The outer RecyclerView holds multiple items, each of which contains a nested RecyclerView. The issue occurs primarily when I scroll quickly, causing stuttering and unresponsiveness that wasn't present before. I've tried using `setHasFixedSize(true)` on both the outer and inner RecyclerViews, but the problem persists. Here’s a simplified version of my layout: ```xml <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent"> <androidx.recyclerview.widget.RecyclerView android:id="@+id/outerRecyclerView" android:layout_width="match_parent" android:layout_height="match_parent" app:layoutManager="LinearLayoutManager" /> </androidx.constraintlayout.widget.ConstraintLayout> ``` And here’s how I set up the inner RecyclerView in the adapter: ```kotlin class OuterAdapter(private val items: List<OuterItem>) : RecyclerView.Adapter<OuterAdapter.OuterViewHolder>() { override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): OuterViewHolder { val view = LayoutInflater.from(parent.context).inflate(R.layout.outer_item, parent, false) return OuterViewHolder(view) } override fun onBindViewHolder(holder: OuterViewHolder, position: Int) { holder.bind(items[position]) } override fun getItemCount() = items.size inner class OuterViewHolder(view: View) : RecyclerView.ViewHolder(view) { private val innerRecyclerView: RecyclerView = view.findViewById(R.id.innerRecyclerView) fun bind(outerItem: OuterItem) { innerRecyclerView.layoutManager = LinearLayoutManager(itemView.context) innerRecyclerView.adapter = InnerAdapter(outerItem.innerItems) innerRecyclerView.setHasFixedSize(true) } } } ``` I also enabled RecyclerView's item animations and tried disabling them, but it didn’t help. The performance seems to improve slightly when the inner RecyclerViews are empty, which suggests that data loading might be a factor. Is there a recommended approach to optimize this setup to reduce the lag? Are there any common pitfalls I might be missing when nesting RecyclerViews? I'm working on a desktop app that needs to handle this.