Android ListView in Kotlin

ListView in Android is a ViewGroup which is used to display a scrollable list of items arranged in multiple rows. It is attached to an adapter which dynamically inserts the items into the list. The main purpose of the adapter is to retrieve data from an array or a database and efficiently push every elements into the list for a desired result.

In this article, we will learn how to use ListView of Android in Kotlin.

Android Adapter

The adapter holds the data fetched from an array and iterates through each item in the data set and generates the respective views for each item of the list. So, we can say it act as an intermediate between the data sources and adapter views such as ListView, and GridView.

Types of Adapters

Different Types of Adapter are mentioned below:

Some Important XML Attributes of ListView

Now, we going to create an Android application, using an array adapter. Open an activity_main.xml file from \res\layout path and write the code like as shown below.

When we have created layout, we need to load the XML layout resource from our activity onCreate() callback method and access the UI element form the XML using findViewById().

package org.geeksforgeeks.demo

import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.ListView
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {
    private lateinit var listView: ListView

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

        // use ArrayAdapter and define an array
        val arrayAdapter: ArrayAdapter<*>
        val users = arrayOf(
            "Python", "Java", "C++", "PHP", "Kotlin", "GoLang", "SQL", "R Language",
            "Android", "Git", "AWS", "Docker", "Azure", "GCP", "JavaScript", "TypeScript"
        )

        // access the listView from xml file
        listView = findViewById(R.id.user_list)
        arrayAdapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, users)
        listView.adapter = arrayAdapter
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    tools:context=".MainActivity">

    <ListView
        android:id="@+id/user_list"
        android:layout_marginTop="32dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

Output:

This is the expected output from the above code:

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