How to use search functionality in custom list view in Android?

This example demonstrates how do I use the search functionality in custom listview in android.
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"?>
<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"
   android:padding="8dp"
   tools:context=".MainActivity">
   <EditText
      android:id="@+id/etSearch"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:hint="Search here" />
   <ListView
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/listView"
      android:layout_below="@id/etSearch"/>
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.java
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
   ListView listView;
   ArrayList<String> months = new ArrayList<>();
   ArrayAdapter<String> arrayAdapter;
   EditText etSearch;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      listView = findViewById(R.id.listView);
      etSearch = findViewById(R.id.etSearch);
      months.add("January");
      months.add("February");
      months.add("March");
      months.add("April");
      months.add("May");
      months.add("June");
      months.add("July");
      months.add("August");
      months.add("September");
      months.add("October");
      months.add("November");
      months.add("December");
      arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, android.R.id.text1, months);
      listView.setAdapter(arrayAdapter);
      etSearch.addTextChangedListener(new TextWatcher() {
         @Override
         public void beforeTextChanged(CharSequence s, int start, int count, int after) {
         }
         @Override
         public void onTextChanged(CharSequence s, int start, int before, int count) {
            arrayAdapter.getFilter().filter(s);
         }
         @Override
         public void afterTextChanged(Editable s) {
         }
      });
   }
}
Step 4 − 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="app.com.sample">
   <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 the android studio, open one of your project's activity files and click 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.