How to write a custom adapter for my list view on Android using Kotlin?

This example demonstrates how to write a custom adapter for my list view on Android using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?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:padding="8dp"    android:orientation="vertical">    <ListView       android:id="@+id/listView"       android:layout_width="match_parent"       android:layout_height="wrap_content" /> </LinearLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.content.Context import android.os.Bundle import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import android.widget.BaseAdapter import android.widget.ListView import android.widget.TextView import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() {    lateinit var listView: ListView    var arrayList: ArrayList<MyData> = ArrayList()    var adapter: MyAdapter? = null    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"       listView = findViewById(R.id.listView)       arrayList.add(MyData(1, " Mashu", "987576443"))       arrayList.add(MyData(2, " Azhar", "8787576768"))       arrayList.add(MyData(3, " Niyaz", "65757657657"))       adapter = MyAdapter(this, arrayList)       listView.adapter = adapter    } } //Class MyAdapter class MyAdapter(private val context: Context, private val arrayList: java.util.ArrayList<MyData>) : BaseAdapter() {    private lateinit var serialNum: TextView    private lateinit var name: TextView    private lateinit var contactNum: TextView    override fun getCount(): Int {       return arrayList.size    }    override fun getItem(position: Int): Any {       return position    }    override fun getItemId(position: Int): Long {       return position.toLong()    }    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View? {       var convertView = convertView       convertView = LayoutInflater.from(context).inflate(R.layout.row, parent, false)       serialNum = convertView.findViewById(R.id.serialNumber)       name = convertView.findViewById(R.id.studentName)       contactNum = convertView.findViewById(R.id.mobileNum)       serialNum.text = " " + arrayList[position].num       name.text = arrayList[position].name       contactNum.text = arrayList[position].mobileNumber       return convertView    } } //Class MyData class MyData(var num: Int, var name: String, var mobileNumber: String) 

Step 4 − Create a layout resource file row.xml and add the following code

<?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"    android:padding="4dp">    <TextView       android:id="@+id/serialNumber"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="Number"       android:textColor="@color/colorPrimary"       android:textSize="16sp" />    <TextView       android:id="@+id/studentName"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="Name"       android:textColor="#000000"       android:textSize="16sp" />    <TextView       android:id="@+id/mobileNum"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:text="Mobile Number"       android:textColor="@android:color/holo_purple"       android:textSize="12sp"       android:textStyle="bold" /> </LinearLayout>

Step 5 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.q11">    <application       android:allowBackup="true"       android:icon="@mipmap/ic_launcher"       android:label="@string/app_name"       android:roundIcon="@mipmap/ic_launcher_round"       android:supportsRtl="true"       android:theme="@style/AppTheme">       <activity android:name=".MainActivity">          <intent-filter>             <action android:name="android.intent.action.MAIN" />             <category android:name="android.intent.category.LAUNCHER" />          </intent-filter>       </activity>    </application> </manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon  from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.

Click here to download the project code.