Android RecyclerView with ItemClickListener in Kotlin Example

Learn how to implement RecyclerView with Item Click Listener in Kotlin.

It's really simple to create a RecyclerView in Kotlin. There are a few steps to implement this feature, which will help you achieve your goal of providing an easy way for users to navigate a list of items.

In this tutorial, we will learn how to implement RecyclerView with ItemClickListener in Kotlin.

Credits: Dev Genius

What is RecyclerView?

The RecyclerView is designed to display large sets of data efficiently and can handle both horizontal and vertical scrolling. It also provides a more modular approach to working with lists and allows for greater flexibility in the way data is presented and interacted with.

For this tutorial, we will use AndroidX, an Android Jetpack library. The androidx.recyclerview the library provides several classes and interfaces to work with the RecyclerView, including:

RecyclerView

This is the main class for working with the RecyclerView. It provides a container for displaying a list of items and handles scrolling, item layout, and recycling of views that are no longer visible on the screen.

RecyclerView.Adapter

This is an abstract class that provides the data and view holder objects for the RecyclerView. It requires implementing several methods to manage the list data, including creating view holders and binding data to them.

RecyclerView.ViewHolder

This is a class that represents a single-item view within the RecyclerView. It holds references to the view objects and provides a way to update the contents of the view based on the data provided by the adapter. You can create multiple instances of RecyclerView.ViewHolder to create multiple view types.

Setting up RecyclerView

First, you'll need to create a RecyclerView in your activity or fragment layout file.

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

Here's an example of what that might look like:

Credit: Android Academics

Next, you need to create a layout file to display items, we named the file item_layout file for the list to display.

item_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:orientation="horizontal"
    android:padding="10dp">

    <androidx.appcompat.widget.AppCompatImageView
        android:id="@+id/imageView"
        android:layout_width="48dp"
        android:src="@tools:sample/avatars"
        android:layout_height="48dp" />

    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:textColor="@color/black"
        android:textSize="16sp"
        tools:text="@tools:sample/first_names" />
</LinearLayout>

Here's an example of what that might look like:

Credit: Android Academics

Pro Tip: If you want to see how your RecyclerView will look like when you run the app, you can implement the tools namespace and use tools properties.

You can specify the list item in tools:listitem="@layout/item_layout" and the number of items you want to display in tools:itemCount="6"

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:listitem="@layout/item_layout"
    tools:itemCount="6"/>

Here's an example of what that might look like:

Credit: Android Academics

Create an adapter and view holder for RecyclerView

Next, you'll need to create an adapter for your RecyclerView. Here's an example of what that might look like:

class MyAdapter(private val data: List<String>, private val onItemClick: (String) -> Unit) :
    RecyclerView.Adapter<MyAdapter.ViewHolder>() {

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        fun bind(item: String) {
            itemView.setOnClickListener { onItemClick(item) }
            val textView = itemView.findViewById<TextView>(R.id.text_view)
            textView.text = item
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = data[position]
        holder.bind(item)
    }

    override fun getItemCount() = data.size
}

This adapter takes a list of strings as its data and a lambda expression onItemClick that will be called when an itemRecyclerView is clicked. The ViewHolder inner class binds the click listener to the item view and sets the text of the text_view view in the item layout.

Set the adapter and onItemClick for RecyclerView

Next, you'll need to create an instance of your adapter and set it as the adapter for your RecyclerView.

Here's an example of what that might look like:

fun setupRecyclerview(){
    val recyclerView = findViewById<RecyclerView>(R.id.my_recycler_view)
    val list = listOf("Item 1", "Item 2", "Item 3")
    
    val adapter = MyAdapter(list) { item ->
        onListItemClick(item)
    }
    recyclerView.layoutManager = LinearLayoutManager(context)
    recyclerView.adapter = adapter
}

// handle list item click here 
fun onListItemClick(val item:String){
    Toast.makeText(context, "Clicked $item", Toast.LENGTH_SHORT).show()
}

This code sets the adapter for the RecyclerView and creates a Toast message that displays the clicked item's text when an item is clicked.

And that's it! You should now have a working RecyclerView in Kotlin with an item click listener.

credits: Android Academics

We hope this article has given you a better understanding of the basics of implementing custom views with Kotlin. We've covered how to create a RecyclerView in Kotlin, and we even explained how to set up an ItemClickListener for it!

• Chapter 2: Learn about RecyclerView with Multiple View Types - Kotlin

• Chapter 3: Android RecyclerView with Endless Scrolling in Kotlin

Check these articles if you want to learn more about RecyclerView from A Step-by-Step Guide on How to Create Different View Types for RecyclerView with Kotlin on Android or how to implement endless scrolling in RecyclerView. 

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