1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     tools:context=".AndroidSeekBarActivity" >
 7 
 8     <ImageView
 9         android:id="@+id/img"
10         android:layout_width="match_parent"
11         android:layout_height="240px"
12         android:src="@drawable/mm" />
13 
14     <SeekBar
15         android:id="@+id/sekbar"
16         android:layout_width="match_parent"
17         android:layout_height="wrap_content"
18         android:max="255"
19         android:progress="255"
20         android:thumb="@drawable/sj" />
21 
22     <RatingBar
23         android:id="@+id/ratbar"
24         android:layout_width="match_parent"
25         android:layout_height="wrap_content"
26         android:max="255"
27         android:numStars="5"
28         android:progress="255"
29         android:stepSize="0.5" />
30 
31 </LinearLayout>

 1 package com.example.androidseekbar;
 2 
 3 import android.os.Bundle;
 4 import android.app.Activity;
 5 import android.view.Menu;
 6 import android.widget.ImageView;
 7 import android.widget.RatingBar;
 8 import android.widget.RatingBar.OnRatingBarChangeListener;
 9 import android.widget.SeekBar;
10 import android.widget.SeekBar.OnSeekBarChangeListener;
11 
12 public class AndroidSeekBarActivity extends Activity {
13 
14     @Override
15     protected void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17         setContentView(R.layout.activity_android_seek_bar);
18 
19         final ImageView img = (ImageView) this.findViewById(R.id.img);
20         SeekBar sekbar = (SeekBar) this.findViewById(R.id.sekbar);
21         sekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
22 
23             @Override
24             public void onStopTrackingTouch(SeekBar seekBar) {
25                 // TODO Auto-generated method stub
26 
27             }
28 
29             @Override
30             public void onStartTrackingTouch(SeekBar seekBar) {
31                 // TODO Auto-generated method stub
32 
33             }
34 
35             @Override
36             public void onProgressChanged(SeekBar seekBar, int progress,
37                     boolean fromUser) {
38                 // 拖动时触发
39                 img.setAlpha(progress);
40             }
41         });
42         
43         RatingBar ratbar=(RatingBar)this.findViewById(R.id.ratbar);
44         ratbar.setOnRatingBarChangeListener(new OnRatingBarChangeListener() {
45             
46             @Override
47             public void onRatingChanged(RatingBar arg0, float rating, boolean arg2) {
48                 //动态改变图片透明度
49                 img.setAlpha((int)(rating*255/5));
50             }
51         });
52     }
53 
54     @Override
55     public boolean onCreateOptionsMenu(Menu menu) {
56         // Inflate the menu; this adds items to the action bar if it is present.
57         getMenuInflater().inflate(R.menu.activity_android_seek_bar, menu);
58         return true;
59     }
60 
61 }