Creating a Anagram Checker Android App in Android Studio with Kotlin

An anagram of a word is another word that contains the same characters, only the order of characters can be different. For example, “abcd” and “dabc” are an anagram of each other. In this article, we will be building an Anagram Checker android app in Android Studio using Kotlin and XML. The app will check whether the entered words are anagrams of each other. If the entered words are an anagram of each other then a Toast will be displayed having the message “Entered words are Anagram” otherwise Toast’s message will be “Entered words are not Anagram”. 

Step by Step Implementation

Step 1: Create a New Project  

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 build.gradle(Module) File

You need to apply the plugin kotlin-android-extensions in the build.gradle module like this

plugins {

   id 'com.android.application'
   id 'kotlin-android'
   id 'kotlin-android-extensions'

}

Step 3: 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. 

XML

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:textColor="#2E7D32"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="40dp"
        android:text="Anagram Checker"
        android:textSize="35sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.LinearLayoutCompat
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="40dp"
        android:orientation="horizontal">

        <TextView
            android:paddingLeft="10dp"
            android:textColor="#2E7D32"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="120dp"
            android:text="Word 1"
            android:textSize="30sp"
            android:textStyle="bold" />

        <EditText
            android:hint="Enter first word"
            android:layout_weight="2"
            android:id="@+id/et_text1"
            android:layout_width="190dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="50dp" />


    </androidx.appcompat.widget.LinearLayoutCompat>

    <androidx.appcompat.widget.LinearLayoutCompat
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:paddingLeft="10dp"
            android:textColor="#2E7D32"
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="120dp"
            android:text="Word 2"
            android:textSize="30sp"
            android:textStyle="bold" />

        <EditText
            android:layout_weight="2"
            android:id="@+id/et_text2"
            android:layout_width="190dp"
            android:hint="Enter second word"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="50dp" />


    </androidx.appcompat.widget.LinearLayoutCompat>

    <Button
        android:id="@+id/check_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        android:backgroundTint="#E67212"
        android:text="Check"
        android:textColor="@color/white" />

</androidx.appcompat.widget.LinearLayoutCompat>

After writing this much code our UI looks like this:

Step 4: 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

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*
import java.util.*

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

        // when user clicks on check button
        check_btn.setOnClickListener {

            val word1: String = et_text1.text.toString()
            val word2: String = et_text2.text.toString()

            //check if words are anagrams of each other.
            val check: Boolean = areAnagram(word1, word2)

            if (check) {
                Toast.makeText(this, "Entered words are anagram", Toast.LENGTH_SHORT).show()
            } else {
                Toast.makeText(this, "Entered words are not anagram", Toast.LENGTH_SHORT).show()
            }
        }
    }

    // function to check
      // whether two strings are
    // anagram of each other
    private fun areAnagram(str1: String, str2: String): Boolean {
        // Both String Length must be Equal
        if (str1.length != str2.length) {
            return false
        }

        // Convert Strings to character Array
        val strArray1 = str1.toCharArray()
        val strArray2 = str2.toCharArray()

        // Sort the Arrays
        Arrays.sort(strArray1)
        Arrays.sort(strArray2)

        // Convert Arrays to String
        val sortedStr1 = String(strArray1)
        val sortedStr2 = String(strArray2)

        // Check Both String Equals
          // or not After Sorting
        // and Return value True or False
        return sortedStr1 == sortedStr2
    }
}

Output: