Android RatingBar 的用法

package com.turbo;

import android.app.Activity;
import android.os.Bundle;
import android.widget.RatingBar;
import android.widget.Toast;

public class AndroidSeekBar extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.seek_bar);
        final RatingBar ratingBar_Small = (RatingBar)findViewById(R.id.ratingbar_small);
        final RatingBar ratingBar_Indicator = (RatingBar)findViewById(R.id.ratingbar_Indicator);
        final  RatingBar ratingBar_default = (RatingBar)findViewById(R.id.ratingbar_default);
        ratingBar_default.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener() {
            
            @Override
            public void onRatingChanged(RatingBar ratingBar, float rating,
                    boolean fromUser) {
                ratingBar_Small.setRating(rating);
                ratingBar_Indicator.setRating(rating);
                Toast.makeText(AndroidSeekBar.this, "rating:" + String.valueOf(rating), Toast.LENGTH_LONG).show();
            }
        });
    }
    
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
  <RatingBar 
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      style="?android:attr/ratingBarStyleIndicator"
      android:id="@+id/ratingbar_Indicator"
      />
  <RatingBar 
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      style="?android:attr/ratingBarStyleSmall"
      android:id="@+id/ratingbar_small"
      android:numStars="20"
      />
  <RatingBar 
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      style="?android:attr/ratingBarStyle"
      android:id="@+id/ratingbar_default"
      />
</LinearLayout>