<RatingBar
 style="@android:style/Widget.DeviceDefault.RatingBar.Small"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginTop="10dp"
 android:isIndicator="false"
 android:numStars="5"
 android:rating="2.5"
 android:stepSize="0.5"/>

ratingBar = (RatingBar) findViewById(R.id.ratingBar);
ratingBar.setRating(3.5f);
ratingBar.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener() {
 @Override
 public void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser) {
  if (fromUser) {//fromUser rating数量是否发生改变
   ratingBar.setRating(rating);
  }
  Log.d(TAG, "rating=" + ratingBar.getRating());
  Log.d(TAG, "fromUser=" + fromUser);
 }
});