title: cannot be resolved or is not a field findViewById
body: <p>I cant find whats wrong with my code I am getting  cannot be resolved or is not a field on findViewById.</p>
  
  <p>the problems lines are:</p>
  
  <pre><code>       playSeekBar = (ProgressBar) findViewById(R.id.progressBar1);
          buttonPlay = (Button) findViewById(R.id.buttonPlay);
           buttonStopPlay = (Button) findViewById(R.id.buttonStopPlay);
  </code></pre>
  
  <p>my xml code is:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent"&gt;
  &lt;ProgressBar android:id="@+id/progressBar1" android:layout_width="wrap_content"    android:layout_height="wrap_content"&gt;&lt;/ProgressBar&gt;
  &lt;Button android:text="Button" android:id="@+id/buttonPlay" android:layout_width="wrap_content" android:layout_height="wrap_content"&gt;&lt;/Button&gt;
  &lt;Button android:text="Button" android:id="@+id/buttonStopPlay" android:layout_width="wrap_content" android:layout_height="wrap_content"&gt;&lt;/Button&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>my code is:</p>
  
  <pre><code> public class radioActivite extends Activity implements OnClickListener {
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.radio_xml);
  
  
  
  
      initializeUIElements();
  
      initializeMediaPlayer();
  }
  
  private void initializeUIElements() {
  
         playSeekBar = (ProgressBar) findViewById(R.id.progressBar1);
  
      playSeekBar.setMax(100);
      playSeekBar.setVisibility(View.INVISIBLE);
  
      buttonPlay = (Button) findViewById(R.id.buttonPlay);
      buttonPlay.setOnClickListener(this);
  
      buttonStopPlay = (Button) findViewById(R.id.buttonStopPlay);
  </code></pre>
  
  <p>tried to clean the code but didn't help me.
  Thanks for the help!</p>