SeekBar 拖动条：拖动条和滚动栏类似，当是拖动条能够拖动滑块改变进度

RatingBar 星级评分条：星级评分条与拖动条相似

SeekBar特有的xml属性

android:thumb    指定一个Arawable对象，作为之定义滑块

RatingBar特有的xml属性

android:isIndicator   是否同意用户改变（true为不同意改动）

android:numStars   共同拥有多少个星级

android:rating   默认的星级

android:stepSize   每次至少改变多少个星级

为了知道改变的进度而做对应的操作，我们须要加入监听

SeekBar 的监听 OnSeekBarChangeListener

RatingBar的监听 OnRatingBarChangeListener

以下我们通过实例来熟悉它们

（1）编写布局文件   activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/linearLayout"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical">

    <ImageView

        android:id="@+id/imgView1"

        android:layout_width="120dp"

        android:layout_height="100dp"

        android:src="@drawable/ic_launcher"/>

    <SeekBar

        android:id="@+id/seekBar"

        android:layout_width="180dp"

        android:layout_height="wrap_content"

        android:thumb="@drawable/ic_launcher"

        android:max="255"

        android:progress="255"/>

      <ImageView

        android:id="@+id/imgView2"

        android:layout_width="120dp"

        android:layout_height="100dp"

        android:src="@drawable/img01"/>

      <RatingBar

          android:id="@+id/reatingBar"

          android:layout_width="wrap_content"

          android:layout_height="wrap_content"

          android:max="255"

          android:progress="255"

          android:rating="5"

          android:stepSize="0.5"

          android:numStars="5"/>

</LinearLayout>

(2)编写 MainActivity.java

package com.example.bar;

import android.annotation.TargetApi;

import android.app.Activity;

import android.os.Build;

import android.os.Bundle;

import android.util.Log;

import android.view.Menu;

import android.widget.ImageView;

import android.widget.RatingBar;

import android.widget.RatingBar.OnRatingBarChangeListener;

import android.widget.SeekBar;

import android.widget.SeekBar.OnSeekBarChangeListener;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)

public class MainActivity extends Activity {

	private ImageView imgViewSB = null; //定义ImageView

	private ImageView imgViewRB = null;

	private SeekBar seekBar = null;  //定义SeekBar

	private RatingBar ratingBar = null; //定义RatingBar

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		//布局组件

		this.imgViewSB = (ImageView) findViewById(R.id.imgView1);

		this.imgViewRB = (ImageView) findViewById(R.id.imgView2);

		this.seekBar = (SeekBar) findViewById(R.id.seekBar);

		this.ratingBar = (RatingBar) findViewById(R.id.reatingBar);

		//seekBar设置监听，改变图片透明度

		this.seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

			@Override

			public void onStopTrackingTouch(SeekBar seekBar) {

				Log.i("onStopTrackingTouch", "停止拖动触发的方法");

			}

			@Override

			public void onStartTrackingTouch(SeekBar seekBar) {

				Log.i("onStartTrackingTouch", "開始拖动触发的方法");

			}

			/**

			 * seekBar: SeekBar对象

			 * progress:拖动条的进度

			 * fromUser:是否用户手动改变

			 */

			@Override

			public void onProgressChanged(SeekBar seekBar, int progress,

					boolean fromUser) {

				imgViewSB.setAlpha(progress);  //设置图片的透明度

				Log.i("onProgressChanged", "拖动滑块位置发生改变时触发的方法");

			}

		});

		//ratingBar设置监听，改变图片透明度

		this.ratingBar.setOnRatingBarChangeListener(new OnRatingBarChangeListener() {

			/**

			 * ratingBar:RatingBar对象

			 * rating :星级的大小

			 * fromUser:是否用户手动改变

			 */

			@Override

			public void onRatingChanged(RatingBar ratingBar, float rating,

					boolean fromUser) {

				imgViewRB.setAlpha((int)(rating*255/5));

			}

		});

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		return true;

	}

}

同意之后，效果例如以下：