How do I use single editTexts with text watcher

edit texts with text watcher

Android EditText with TextWatcher

The TextView class has a subclass named Android EditText which is used for entering and modifying text. The input type must be defined in the inputType property of EditText while using EditText width. It thus configures the keyboard according to the input. To watch the changes made over EditText, the TextWatcher interface is used by the EditText, for which the addTextChangedListener() method is called by the EditText.

Methods of TextWatcher:

beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3): Before making any change over EditText, the beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) method is executed.
onTextChanged(CharSequence cs, int arg1, int arg2, int arg3): While making any change over EditText, the onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) method is executed.
afterTextChanged(Editable arg0): After change is made over EditText, the afterTextChanged(Editable arg0) method is executed.

Example of EditText with TextWatcher():

In the below example, we are demonstrating the implementation of the EditText with TextWatcher to search data from ListView.

activity_main.xml:

In the activity_main.xml file, we will add the EditText and ListView.

<?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">
 
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/editText"
        android:inputType="text"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />
 
    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/listView"
        android:layout_below="@+id/editText"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />
</RelativeLayout>

Activity class:(File: MainActivity.java)

package com.example.radioapp;
 
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 android.support.v7.app.AppCompatActivity;
import android.widget.Toast;
 
public class MainActivity extends AppCompatActivity {
 
    private ListView lv;
    private EditText editText;
    private ArrayAdapter<String> adapter;
 
    private String products[] = {"A1", "B2","C3", "D4", "E5", "F6",
            "G7", "H8","I9", "J10"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        lv = (ListView) findViewById(R.id.listView);
        editText = (EditText) findViewById(R.id.editText);
        adapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.product_name, products);
        lv.setAdapter(adapter);
 
        editText.addTextChangedListener(new TextWatcher() {
 
            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                adapter.getFilter().filter(cs);
            }
 
            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
                Toast.makeText(getApplicationContext(),"before text change",Toast.LENGTH_LONG).show();
            }
 
            @Override
            public void afterTextChanged(Editable arg0) {
                Toast.makeText(getApplicationContext(),"Text changed",Toast.LENGTH_LONG).show();
            }
        });
    }
}