title: setBackgroundColor in android
body: <p><img src="https://i.stack.imgur.com/bRkji.png" alt="enter image description here"></p>
  
  <p>In this simple game I want to change the background color of the button that I press. But I get the following result, the buttons appearance becomes not good (the shape becomes different):</p>
  
  <pre><code>pressedButton.setBackgroundColor(Color.RED);
  </code></pre>
  
  <p>Is there a nicer way to do that? Thanks.</p>
  
  <p>[Edit: my full code]</p>
  
  <pre><code>package com.example.xo_game;
  
  import android.os.Bundle;
  import android.app.Activity;
  import android.graphics.Color;
  import android.view.Menu;
  import android.view.View;
  import android.widget.Button;
  
  public class MainActivity extends Activity {
  
      Button[] btns;
      char[][] gameState = new char[3][3];
      char turn = 'X';
  
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          Button[] btns = new Button[9];
  
          btns[0] = (Button) findViewById(R.id.btn1);
          btns[1] = (Button) findViewById(R.id.btn2);
          btns[2] = (Button) findViewById(R.id.btn3);
  
          btns[3] = (Button) findViewById(R.id.btn4);
          btns[4] = (Button) findViewById(R.id.btn5);
          btns[5] = (Button) findViewById(R.id.btn6);
  
          btns[6] = (Button) findViewById(R.id.btn7);
          btns[7] = (Button) findViewById(R.id.btn8);
          btns[8] = (Button) findViewById(R.id.btn9);
  
          for (int i = 0; i &lt; 9; i++) {
              btns[i].setTag(i);
              btns[i].setOnClickListener(clickListener);
              gameState[i / 3][i % 3] = 'E';
          }
      }
  
      View.OnClickListener clickListener = new View.OnClickListener() {
  
          public void onClick(View v) {
              Button pressedButton = (Button) v;
  
              int indexOfPressedButton = Integer.parseInt(pressedButton.getTag()
                      .toString());
  
              int row = indexOfPressedButton / 3;
              int col = indexOfPressedButton % 3;
  
              if (gameState[row][col] != 'E')
                  return;
  
              gameState[row][col] = turn;
  
              String turnAsString = String.valueOf(turn);
  
              pressedButton.setText(turnAsString);
  
              if (turn == 'X') {
                  pressedButton.setBackgroundColor(Color.RED);
                  turn = 'O';
              } else {
                  pressedButton.setBackgroundColor(Color.GREEN);
                  turn = 'X';
              }
          }
      };
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          getMenuInflater().inflate(R.menu.activity_main, menu);
          return true;
      }
  }
  </code></pre>