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How to implement swipe to delete in a RecyclerView in Kotlin Android

How to implement swipe to delete in a RecyclerView in Kotlin Android.

Here's a detailed step-by-step tutorial on how to implement swipe to delete in a RecyclerView in Kotlin Android.

Step 1: Set up the project​

  • Create a new Android project in Kotlin.
  • Add the necessary dependencies to your project's build.gradle file:
implementation 'androidx.recyclerview:recyclerview:1.2.1'

Step 2: Create the RecyclerView layout​

  • Open the activity_main.xml file and add a RecyclerView element:
<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    />

Step 3: Create the RecyclerView item layout​

  • Create a new XML file called item_layout.xml and define the layout for each item in the RecyclerView.
  • For example, you can use a TextView to display the item's text:
<TextView
    android:id="@+id/itemText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    />

Step 4: Create the RecyclerView adapter​

  • Create a new Kotlin file called RecyclerViewAdapter.kt and define a class for the RecyclerView adapter.
  • Extend the RecyclerView.Adapter class and implement the necessary methods:
class RecyclerViewAdapter(private val itemList: MutableList<String>) :
    RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>() {

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val itemText: TextView = itemView.findViewById(R.id.itemText)
    }

    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 = itemList[position]
        holder.itemText.text = item
    }

    override fun getItemCount(): Int {
        return itemList.size
    }
}

Step 5: Set up the RecyclerView in the MainActivity​

  • Open the MainActivity.kt file and initialize the RecyclerView and the adapter:
class MainActivity : AppCompatActivity() {
    private lateinit var recyclerView: RecyclerView
    private lateinit var adapter: RecyclerViewAdapter
    private lateinit var itemList: MutableList<String>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        recyclerView = findViewById(R.id.recyclerView)
        itemList = mutableListOf("Item 1", "Item 2", "Item 3") // Replace with your actual data
        adapter = RecyclerViewAdapter(itemList)

        recyclerView.adapter = adapter
        recyclerView.layoutManager = LinearLayoutManager(this)

        // Add swipe to delete functionality here
    }
}

Step 6: Implement swipe to delete functionality​

  • Add the following code inside the onCreate() method in MainActivity.kt, after setting up the RecyclerView:
val itemTouchHelperCallback = object : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT) {
    override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
        return false
    }

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
        val position = viewHolder.adapterPosition
        itemList.removeAt(position)
        adapter.notifyItemRemoved(position)
    }
}

val itemTouchHelper = ItemTouchHelper(itemTouchHelperCallback)
itemTouchHelper.attachToRecyclerView(recyclerView)

That's it! You have successfully implemented swipe to delete in a RecyclerView using Kotlin in Android.