读取 android 设备的电池信息

简短说明(Quick explanation):
通过创建BroadcastReceiver来侦测系统中有关电池Intent(ACTION_BATTERY_CHANGED)的变化，一旦有接收到相关事件，将会读取当前电量情况，并通过TextViews显示在当前屏幕。

 1  public   class  MyButteryDemo  extends  Activity {
 2       private  Button button  =   null ;
 3 
 4      @Override
 5       public   void  onCreate(Bundle savedInstanceState) {
 6           super .onCreate(savedInstanceState);
 7          setContentView(R.layout.main);
 8 
 9          button  =  (Button) findViewById(R.id.btn);
10          button.setOnClickListener( new  OnClickListenerImpl());
11      }
12 
13       private   class  OnClickListenerImpl  implements  OnClickListener {
14 
15          @Override
16           public   void  onClick(View arg0) {
17              ButteryBroadcastReceiver receiver  =   new  ButteryBroadcastReceiver();
18              IntentFilter filter  =   new  IntentFilter(
19                      Intent.ACTION_BATTERY_CHANGED);
20              MyButteryDemo. this .registerReceiver(receiver, filter);
21          }
22 
23      }
24  }

 1  public   class  ButteryBroadcastReceiver  extends  BroadcastReceiver {
 2 
 3      @Override
 4       public   void  onReceive(Context context, Intent intent) {
 5 
 6           if  (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())) {
 7               int  level  =  intent.getIntExtra( " level " ,  0 );
 8               int  scale  =  intent.getIntExtra( " scale " ,  100 );
 9              Dialog dialog  =   new  AlertDialog.Builder(context)
10                      .setTitle( " 电池电量 " )
11                      .setMessage(
12                               " 电池电量为： "   +  String.valueOf(level  *   100   /  scale)
13                                       +   " % " ).setNegativeButton( " 关闭 " ,  new  DialogInterface.OnClickListener() {
14                                          
15                                          @Override
16                                           public   void  onClick(DialogInterface dialog,  int  which) {
17                                               //  TODO Auto-generated method stub
18                                              
19                                          }
20                                      }).create();
21              dialog.show();
22          }
23      }
24 
25  }