title: Class is not abstract and does not override abstract method onClick(View) in OnClickListener
body: <p>I am new to android development and am trying to create an app to check if a given string is Palindrome or not. What is the problem with this code?</p>
  
  <p>I am using Android Studio.</p>
  
  <p>The error is</p>
  
  <blockquote>
    <p>Class is not abstract and does not override abstract method
    onClick(View) in OnClickListener</p>
  </blockquote>
  
  <pre><code>package com.example.myapplication;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.widget.Button;
  import android.widget.EditText;
  import android.widget.TextView;
  import java.lang.String;
  import java.lang.StringBuffer;
  
  public class Alaukik extends AppCompatActivity implements View.OnClickListener
  
  {
      private View v;
      final TextView textView = (TextView) findViewById(R.id.textView2);
      final EditText editText = (EditText) findViewById(R.id.editText);
  
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_alaukik);
  
          final Button checkbutton = (Button) findViewById(R.id.button);
          checkbutton.setOnClickListener(new View.OnClickListener() {
  
              public void onClick(View v) {
                  String str = editText.getText().toString();
                  StringBuffer b = new StringBuffer(str);
                  String reved = b.reverse().toString();
                  if (reved.equals(str)) {
                      textView.setText("Palindrome");
                  } else {
                      textView.setText("Not a Palindrome");
  
                  }
              }
          });
      }
  
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.menu_alaukik, menu);
          return true;
      }
  
      @Override
      public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will
          // automatically handle clicks on the Home/Up button, so long
          // as you specify a parent activity in AndroidManifest.xml.
          int id = item.getItemId();
  
          //noinspection SimplifiableIfStatement
          if (id == R.id.action_settings) {
              return true;
          }
  
          return super.onOptionsItemSelected(item);
      }
  
  
  }
  </code></pre>