How to implement  RecyclerView using DiffUtil in android studio Kotlin

Hello Guys, In this post we are going to learn how we can implement RecyclerView using DiffUtil and Kotlin. To implement a RecyclerView in Android using Kotlin and DiffUtil, you need to do following:

1. Define a layout file for the item. This layout file will be used to display each item in the RecyclerView.
2. Define a layout file for the RecyclerView. This layout file will contain the RecyclerView widget.
3. Define an adapter class that extends ListAdapter and provides a DiffUtil.ItemCallback to calculate the differences between items.
4. Define a view holder class that extends RecyclerView.ViewHolder and includes any necessary code for handling clicks or other events.
5. Set the adapter for the RecyclerView using the adapter property.
6. To update the data for the RecyclerView, call the submitList method of the adapter with the new list of items.

Here is an example of the code for implementing a RecyclerView in Android using Kotlin and DiffUtil:

Step 1:- Create an item_layout.xml file:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/text_view_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp" />

</LinearLayout>

Step 2:-Create an activity_main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

Step 3:- Create a new kotlin file with name MyAdapter.kt:

class MyAdapter : ListAdapter<String, MyViewHolder>(DIFF_CALLBACK) {

    companion object {
        private val DIFF_CALLBACK = object : DiffUtil.ItemCallback<String>() {
            override fun areItemsTheSame(oldItem: String, newItem: String): Boolean {
                return oldItem == newItem
            }

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

    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))
    }
}

class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
    fun bind(item: String) {
        itemView.text_view_name.text = item
    }
}

Step 4 :- Add these line in MainActivity.kt file:

val adapter = MyAdapter()
recycler_view.adapter = adapter
val items = listOf("Item 1", "Item 2", "Item 3")
adapter.submitList(items)

I hope this helps! Let me know if you have any questions.