Android之手机电池电量应用

原理概述：

    手机电池电量的获取在应用程序的开发中也很常用，Android系统中手机电池电量发生变化的消息是通过Intent广播来实现的，常用的Intent的Action有  Intent.ACTION_BATTERY_CHANGED（电池电量发生改变时）、Intent.ACTION_BATTERY_LOW（电池电量达到下限时）、和Intent.ACTION_BATTERY_OKAY（电池电量从低恢复到高时）。

    当需要在程序中获取电池电量的信息时，需要为应用程序注册BroadcastReceiver组件，当特定的Action事件发生时，系统将会发出相应的广播，应用程序就可以通过BroadcastReceiver来接受广播，并进行相应的处理。

main.xml布局文件

  
    

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

   
     <
   
     LinearLayout xmlns:android
   
     =
   
     "
   
     http://schemas.android.com/apk/res/android
   
     "
   
     
 android:orientation
   
     =
   
     "
   
     vertical
   
     "
   
      
 android:layout_width
   
     =
   
     "
   
     fill_parent
   
     "
   
     
 android:layout_height
   
     =
   
     "
   
     fill_parent
   
     "
   
     >
   
     
 
   
     <
   
     ToggleButton android:id
   
     =
   
     "
   
     @+id/tb
   
     "
   
     
 android:layout_width
   
     =
   
     "
   
     fill_parent
   
     "
   
     
 android:layout_height
   
     =
   
     "
   
     wrap_content
   
     "
   
      
 android:textOn
   
     =
   
     "
   
     停止获取电量信息
   
     "
   
     
 android:textOff
   
     =
   
     "
   
     获取电量信息
   
     "
   
      
   
     />
   
     
 
   
     <
   
     TextView android:id
   
     =
   
     "
   
     @+id/tv
   
     "
   
      
 android:layout_width
   
     =
   
     "
   
     fill_parent
   
     "
   
     
 android:layout_height
   
     =
   
     "
   
     wrap_content
   
     "
   
      
   
     />
   
     

   
     </
   
     LinearLayout
   
     >
  
    

BatteryActivity类

  
    

   
     package
   
      com.ljq.activity;


   
     import
   
      android.app.Activity;

   
     import
   
      android.content.BroadcastReceiver;

   
     import
   
      android.content.Context;

   
     import
   
      android.content.Intent;

   
     import
   
      android.content.IntentFilter;

   
     import
   
      android.os.Bundle;

   
     import
   
      android.widget.CompoundButton;

   
     import
   
      android.widget.TextView;

   
     import
   
      android.widget.ToggleButton;

   
     import
   
      android.widget.CompoundButton.OnCheckedChangeListener;



   
     public
   
      
   
     class
   
      BatteryActivity 
   
     extends
   
      Activity {
 
   
     private
   
      ToggleButton tb
   
     =
   
     null
   
     ;
 
   
     private
   
      TextView tv
   
     =
   
     null
   
     ;
 
   
     private
   
      BatteryReceiver receiver
   
     =
   
     null
   
     ;
 
 
 @Override
 
   
     public
   
      
   
     void
   
      onCreate(Bundle savedInstanceState) {
 
   
     super
   
     .onCreate(savedInstanceState);
 setContentView(R.layout.main);
 
 receiver
   
     =
   
     new
   
      BatteryReceiver();
 tv
   
     =
   
     (TextView)findViewById(R.id.tv);
 tb
   
     =
   
     (ToggleButton)findViewById(R.id.tb);
 tb.setOnCheckedChangeListener(
   
     new
   
      OnCheckedChangeListener(){
 
   
     public
   
      
   
     void
   
      onCheckedChanged(CompoundButton compoundButton, 
   
     boolean
   
      isChecked) {
 
   
     //
   
     获取电池电量
   
     

   
      
   
     if
   
     (isChecked){
 IntentFilter filter
   
     =
   
     new
   
      IntentFilter(Intent.ACTION_BATTERY_CHANGED);
 registerReceiver(receiver, filter);
   
     //
   
     注册BroadcastReceiver
   
     

   
      }
   
     else
   
      {
 
   
     //
   
     停止获取电池电量
   
     

   
      unregisterReceiver(receiver);
 tv.setText(
   
     null
   
     );
 }
 
 }
 });
 
 }
 
 
   
     private
   
      
   
     class
   
      BatteryReceiver 
   
     extends
   
      BroadcastReceiver{
 @Override
 
   
     public
   
      
   
     void
   
      onReceive(Context context, Intent intent) {
 
   
     int
   
      current
   
     =
   
     intent.getExtras().getInt(
   
     "
   
     level
   
     "
   
     );
   
     //
   
     获得当前电量
   
     

   
      
   
     int
   
      total
   
     =
   
     intent.getExtras().getInt(
   
     "
   
     scale
   
     "
   
     );
   
     //
   
     获得总电量
   
     

   
      
   
     int
   
      percent
   
     =
   
     current
   
     *
   
     100
   
     /
   
     total;
 tv.setText(
   
     "
   
     现在的电量是
   
     "
   
     +
   
     percent
   
     +
   
     "
   
     %。
   
     "
   
     );
 }
 }
 

}
  
    

运行结果