How to do reverse of string in Android?

This example demonstrates How to do reverse of string 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"?>
<LinearLayout xmlns:android = "https://schemas.android.com/apk/res/android"
   xmlns:tools = "https://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   tools:context = ".MainActivity"
   android:orientation = "vertical">
   <EditText
      android:id = "@+id/name"
      android:layout_width = "match_parent"
      android:hint = "Enter Name"
      android:layout_height = "wrap_content" />
   <LinearLayout
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content">
      <Button
         android:id = "@+id/save"
         android:text = "Save"
         android:layout_width = "wrap_content"
         android:layout_height = "wrap_content" />
   </LinearLayout>
   <TextView
      android:id = "@+id/textview"
      android:layout_width = "match_parent"
      android:layout_height = "match_parent" />
</LinearLayout>

In the above code, we have taken name and when user click on button it will print reverse of edittext value.

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

package com.example.andy.myapplication;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.util.HashMap;
public class MainActivity extends AppCompatActivity {
   EditText name;
   HashMap<Character, Integer> charCountMap;
   TextView textview;
   @Override
   protected void onCreate(Bundle readdInstanceState) {
      super.onCreate(readdInstanceState);
      setContentView(R.layout.activity_main);
      name = findViewById(R.id.name);
      textview = findViewById(R.id.textview);
      charCountMap = new HashMap<>();
      findViewById(R.id.save).setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if (!name.getText().toString().isEmpty()) {
               StringBuffer c = new StringBuffer(name.getText().toString());
               textview.setText(c.reverse());
               Toast.makeText(MainActivity.this, "Inserted", Toast.LENGTH_LONG).show();
            } else {
               name.setError("Enter NAME");
            }
         }
      });
   }
}

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 –

In the above result, we are inserting name but textview is showing in revese order.