The type new View.OnClickListener(){} must implement the inherited abstract method View.Onclicklis

public class MainActivity extends Activity {
 protected Button startBrew = null;
   
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  startBrew = (Button) findViewById(R.id.brew_start);
  startBrew.setOnClickListener(new StartButtonListener());
 }
 
 class StartButtonListener implements android.view.View.OnClickListener {  
  @Override 
  public void onClick(View v) {   
  // TODO Auto-generated method stub
   findViewById(R.id.textView0).setBackgroundColor(Color.BLUE);
  }
 }

@Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }
}