7.Android之评分条RatingBar和拖动条SeekBar学习

评分条RatingBar和拖动条SeekBar很常见，今天来学习下。

(1)RatingBar评分条

如图:

 1 <RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context="com.example.ratingbar.MainActivity" >
10 
11     <RatingBar
12         android:id="@+id/ratingBar1"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content"
15         android:layout_alignParentLeft="true"
16         android:layout_alignParentTop="true"
17         android:layout_marginLeft="22dp"
18         android:layout_marginTop="25dp" />
19 
20 </RelativeLayout>

RatingBar监听事件：public void setOnRatingBarChangeListener (RatingBar.OnRatingBarChangeListener listener)

(2)拖动他SeekBar使用

首先从工具中拖入一个SeekBar和两个TextView，如图：

代码如下：

 1 <RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context="com.example.ratingbar.MainActivity" >
10 
11     <SeekBar
12         android:id="@+id/seekBar1"
13         android:max="100"
14         android:progress="50"
15         android:secondaryProgress="75"
16         android:layout_width="match_parent"
17         android:layout_height="wrap_content"
18         android:layout_alignParentLeft="true"
19         android:layout_alignParentTop="true"
20         android:layout_marginTop="35dp" />
21 
22     <TextView
23         android:id="@+id/info1"
24         android:layout_width="wrap_content"
25         android:layout_height="wrap_content"
26         android:layout_alignLeft="@+id/seekBar1"
27         android:layout_below="@+id/seekBar1"
28         android:layout_marginTop="24dp"/>
29 
30     <TextView
31         android:id="@+id/info2"
32         android:layout_width="wrap_content"
33         android:layout_height="wrap_content"
34         android:layout_alignLeft="@+id/info1"
35         android:layout_below="@+id/info1"
36         android:layout_marginTop="32dp"/>
37 
38 </RelativeLayout>

然后我们实现OnSeekBarChangeListener接口：public class MainActivity extends Activity implements OnSeekBarChangeListener{...} ,此接口共需要监听三个事件，分别是：
                 数值改变（onProgressChanged）
                 开始拖动（onStartTrackingTouch）
                 停止拖动（onStopTrackingTouch）

完整代码如下：

 1 package com.example.ratingbar;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.view.Menu;
 6 import android.view.MenuItem;
 7 import android.widget.SeekBar;
 8 import android.widget.SeekBar.OnSeekBarChangeListener;
 9 import android.widget.TextView;
10 
11 //实现OnSeekBarChangeListener接口
12 public class MainActivity extends Activity implements OnSeekBarChangeListener {
13 
14     private SeekBar sbVolumer=null;  
15     private TextView info1=null;  
16     private TextView info2=null;  
17     
18     @Override
19     protected void onCreate(Bundle savedInstanceState) {
20         super.onCreate(savedInstanceState);
21         setContentView(R.layout.activity_main);
22         
23         sbVolumer = (SeekBar) findViewById(R.id.seekBar1);
24         sbVolumer.setOnSeekBarChangeListener(this);
25         info1 = (TextView) findViewById(R.id.info1);
26         info2 = (TextView) findViewById(R.id.info2);
27     }
28 
29     @Override
30     public boolean onCreateOptionsMenu(Menu menu) {
31         // Inflate the menu; this adds items to the action bar if it is present.
32         getMenuInflater().inflate(R.menu.main, menu);
33         return true;
34     }
35 
36     @Override
37     public boolean onOptionsItemSelected(MenuItem item) {
38         // Handle action bar item clicks here. The action bar will
39         // automatically handle clicks on the Home/Up button, so long
40         // as you specify a parent activity in AndroidManifest.xml.
41         int id = item.getItemId();
42         if (id == R.id.action_settings) {
43             return true;
44         }
45         return super.onOptionsItemSelected(item);
46     }
47 
48     @Override
49     public void onProgressChanged(SeekBar seekBar, int progress,
50             boolean fromUser) {
51          
52         info1.setText("当前值： " + progress);
53     }
54 
55     @Override
56     public void onStartTrackingTouch(SeekBar seekBar) {
57          
58         info2.setText("正在改变当前值");
59     }
60 
61     @Override
62     public void onStopTrackingTouch(SeekBar seekBar) {
63         info2.setText("停止拖动");    
64     }
65 }

运行效果：