评分条RatingBar Android

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RatingBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/ratingbar" />

</LinearLayout>

package com.example.yanlei.my;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.RatingBar;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    //声明变量
    //声明RatingBar
    private RatingBar rbScore=null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //获取RatingBar
        rbScore = (RatingBar)findViewById(R.id.ratingbar);

        //设置监听事件
        rbScore.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener(){
            public void onRatingChanged(RatingBar ratingBar, float rating,boolean fromUser) {
                Toast.makeText(getApplication(), "rating:"+String.valueOf(rating),Toast.LENGTH_SHORT).show();
            }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}