How to Counting Chars in EditText Changed Listener in Android?

Some situations, we have to restrict an edit text for some characters. To solve this situation, in this example demonstrate how to Counting Chars in Edit Text Changed Listener.

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 = "https://schemas.android.com/apk/res/android"
   android:id = "@+id/parent"
   xmlns:tools = "https://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   tools:context = ".MainActivity"
   android:gravity = "center"
   android:background = "#33FFFF00"
   android:orientation = "vertical">
   <EditText
      android:id = "@+id/text"
      android:textSize = "18sp"
      android:layout_width = "match_parent"
      android:layout_height = "wrap_content" />
</LinearLayout>

In the above code, we have taken one edit text. It going to check the length of the entered characters, if it exceeds 5 then it shows an error message.

Step 3 - Add the following code to src/MainActivity.java

package com.example.andy.myapplication;
import android.app.ActivityManager;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.os.VibrationEffect;
import android.os.Vibrator;
import android.support.annotation.RequiresApi;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
   int view = R.layout.activity_main;
   EditText text;
   @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(view);
      text = findViewById(R.id.text);
      text.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) { }
         @Override
         public void afterTextChanged(Editable s) {
            if(s.toString().length()>5) {
               text.setError("It allows only 5 character");
            }else{
               text.setError(null);
            }
         }
      });
   }
}

In the above code, we have used text changed listener, after changed text we are validating text as shown below -

text.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) { }
   @Override
   public void afterTextChanged(Editable s) {
      if(s.toString().length()>5) {
         text.setError("It allows only 5 character");
      }else{
         text.setError(null);
      }
}
});

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 Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen -

When you enter 5 characters, it does not show any error. if you enter more than 5 characters. it will show an error as shown below -