<?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>

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+"%。");
    }
  }
}