SearchView in Android with Kotlin

SearchView is a widget in android which provides a search interface with the help of which users can be able to make searches within the given list of data. In this search view, the user has to specify the search query. According to the search, query results will be populated within the listview. In this article, we will take a look at How to implement SearchView in Android ListView in Kotlin. We will be building a simple application in which we will be displaying the list of programming languages within listview. We will be also displaying a search view with which users can filter the data within the list view according to the search query. A sample video is given below to get an idea about what we are going to do in this article.

Note: To implement Search View in Android using Java, check out the following article: Search View in Android ListView in Java

Step by Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Kotlin as the programming language.

Step 2: Working with the activity_main.xml file

Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file. Comments are added inside the code to understand the code in more detail.

XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    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"
    tools:context=".MainActivity">

    <!--Search view for filtering list view-->
    <SearchView
        android:id="@+id/idSV"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:iconifiedByDefault="false"
        android:padding="4dp"
        android:queryHint="Search Programming language" />

    <!--List View from which data is to be searched
         for different programming languages-->
    <ListView
        android:id="@+id/idLVProgrammingLanguages"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_below="@id/idSV" />

</RelativeLayout>

Step 3: Working with the MainActivity.kt file

Go to the MainActivity.kt file and refer to the following code. Below is the code for the MainActivity.kt file. Comments are added inside the code to understand the code in more detail.

Kotlin

package com.gtappdevelopers.kotlingfgproject

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


class MainActivity : AppCompatActivity() {
    // on below line we are
    // creating variables for listview
    lateinit var programmingLanguagesLV: ListView

    // creating array adapter for listview
    lateinit var listAdapter: ArrayAdapter<String>

    // creating array list for listview
    lateinit var programmingLanguagesList: ArrayList<String>;

    // creating variable for searchview
    lateinit var searchView: SearchView

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

        // initializing variables of list view with their ids.
        programmingLanguagesLV = findViewById(R.id.idLVProgrammingLanguages)
        searchView = findViewById(R.id.idSV)

        // initializing list and adding data to list
        programmingLanguagesList = ArrayList()
        programmingLanguagesList.add("C")
        programmingLanguagesList.add("C#")
        programmingLanguagesList.add("Java")
        programmingLanguagesList.add("Javascript")
        programmingLanguagesList.add("Python")
        programmingLanguagesList.add("Dart")
        programmingLanguagesList.add("Kotlin")
        programmingLanguagesList.add("Typescript")

        // initializing list adapter and setting layout
        // for each list view item and adding array list to it.
        listAdapter = ArrayAdapter<String>(
            this,
            android.R.layout.simple_list_item_1,
            programmingLanguagesList
        )

        // on below line setting list
        // adapter to our list view.
        programmingLanguagesLV.adapter = listAdapter

        // on below line we are adding on query
        // listener for our search view.
        searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
            override fun onQueryTextSubmit(query: String?): Boolean {
                // on below line we are checking
                // if query exist or not.
                if (programmingLanguagesList.contains(query)) {
                    // if query exist within list we
                    // are filtering our list adapter.
                    listAdapter.filter.filter(query)
                } else {
                    // if query is not present we are displaying
                    // a toast message as no  data found..
                    Toast.makeText(this@MainActivity, "No Language found..", Toast.LENGTH_LONG)
                        .show()
                }
                return false
            }

            override fun onQueryTextChange(newText: String?): Boolean {
                // if query text is change in that case we
                // are filtering our adapter with
                // new text on below line.
                listAdapter.filter.filter(newText)
                return false
            }
        })
    }
}

Now run your application to see the output of it. 

Output: