title: Android Ratingbar has no response
body: <p>I am making a Ratingbar to allow user to rate for something.
  Thus,I use this java code </p>
  
  <pre><code>    setContentView(R.layout.restaurant_detail);
      value=(TextView) findViewById(R.id.textView23) ;
      rb=(RatingBar) findViewById(R.id.ratingBar);
      rb.setOnRatingBarChangeListener(new 
      RatingBar.OnRatingBarChangeListener(){
      @Override
      public void onRatingChanged(RatingBar ratingBar,float rating,boolean fromUser){
          value.setText("Rated:"+rating)}
      });
  </code></pre>
  
  <p>and this xml code</p>
  
  <pre><code>&lt;RatingBar
        android:id="@+id/ratingBar"
        style="?android:attr/ratingBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:isIndicator="true"
        android:numStars="5"
        android:rating="4.5"
        android:stepSize="0.5" /&gt;
  
  &lt;TextView
        android:id="@+id/textView23"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="TextView" /&gt;
  </code></pre>
  
  <p>but the Ratingbar does not change when I press on it. I have done many searching in vain,please help me to solve the problem.</p>