RecyclerView with Kotlin in Android

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Hi,

                                 This is my first post in Blog. So lets begin with something new, fun and easy ;)
Lets do RecyclerView with Kotlin.


1. Create New Project :

First, create a new project in Android Studio with Kotlin support.





2. Design Layouts :

  •  Design layout with RecyclerView  as below:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        tools:layout_editor_absoluteX="8dp"
        tools:layout_editor_absoluteY="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
</android.support.constraint.ConstraintLayout>

  •  Then design layout for each row item of RecyclerView

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <android.support.v7.widget.CardView
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_margin="5dp"
        android:elevation="3dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/itemid"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="5dp"/>

        <TextView
            android:id="@+id/name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="5dp"/>

    </LinearLayout>
    </android.support.v7.widget.CardView>
    
</android.support.constraint.ConstraintLayout>


3. Finally, Code :

  • Create Model class

User.kt

data class User(val name: String, val phone: String)

  •   Let's create adapter for RecyclerView , to display data

RecyclerAdapter.kt

class RecyclerAdapter(val context: Context, val data: ArrayList<User>) :
        RecyclerView.Adapter<RecyclerAdapter.ViewHolder>() {


    override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
        if (holder != null)
            holder.bindItems(data.get(position))
    }

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

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

    class ViewHolder(itemView: View?) : RecyclerView.ViewHolder(itemView) {
        fun bindItems(map: User) {
            itemView.itemid.text = "Name : " + map.name
            itemView.name.text = "Phone : " + map.phone
        }
    }
}

  •  Then initiate and set adapter for RecyclerView

MainActivity.kt

Goodbye to all findViewById declarations in Kotlin. Whewww!!

class MainActivity : AppCompatActivity() {

    /** Declare variables **/
    private var list: ArrayList<User> = ArrayList<User>()
    lateinit var adapter: RecyclerAdapter

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

        /** Adding values **/
        list.add(User("Anisha", "9876543210"))
        list.add(User("Karthik", "9876543210"))
        list.add(User("Vino", "9876543210"))
        list.add(User("Percy", "95673210"))

        /** Adding layoutManager to RecyclerView **/
        recyclerView.layoutManager = LinearLayoutManager(this, LinearLayout.VERTICAL, false)

        /** Setting adapter to RecyclerView **/
        adapter = RecyclerAdapter(this@MainActivity, list);
        recyclerView.adapter = adapter

    }
}

4. Run Application :

    • Now, lets run the application. 




                                  Hurray!! Now we have implemented it with ease. 

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