根据当前电量计算可待机时间（在线等）

小弟最近开心系统设置我们的界面和以往2.2和2.3都一样所以里面的功能全部都是要重写，根据UI的改变，我们的电量使用情况变成了，显示，当前电量，可待机时间，打开WIFI可待机时间，可支持浏览网页时间，可支持观看视频时间。。
现在系统的当前电量可以获取到，但后面：可待机时间，打开WIFI可待机时间，可支持浏览网页时间，可支持观看视频时间
这些该如何计算，请那位做过的朋友提供一下计算的公式和相关代码，以下我提供一下我的电量获取的Demo
public class Level extends Activity {  private IntentFilter   mIntentFilter;   
@Override
protected void onCreate(android.os.Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

/*setContentView(R.layout.level);
tvBatteryChanged=(TextView)findViewById(R.id.tLevel);
registerReceiver(batteryChangedReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));*/
 mIntentFilter = new IntentFilter(); 
 mIntentFilter.addAction(Intent.ACTION_BATTERY_CHANGED); 
 registerReceiver(mIntentReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

};  protected void onResume() 
  { 
    super.onResume();     
    registerReceiver(mIntentReceiver, mIntentFilter); 
  } 
   private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() { 
       @Override 
       public void onReceive(Context context, Intent intent) { 
           String action = intent.getAction(); 
           if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
               System.out.println("Battery"+ "" + intent.getIntExtra("level", 0));                
               System.out.println("Battery"+ "" + intent.getIntExtra("scale", 0));                
               System.out.println("Battery"+"" + intent.getIntExtra("voltage", 0));                
               System.out.println("Battery" + intent.getIntExtra("temperature", 0)); 
               System.out.println("Battery"+"" + intent.getIntExtra("status", BatteryManager.BATTERY_STATUS_UNKNOWN)); 
               
               System.out.println("Battery" + intent.getIntExtra("plugged", 0)); 
               
               System.out.println("Battery" + intent.getIntExtra("health", BatteryManager.BATTERY_HEALTH_UNKNOWN));
            
               int status = intent.getIntExtra("status", 0);
               int health = intent.getIntExtra("health", 0);
               int plugged = intent.getIntExtra("plugged", 0);                String statusString = "";
               String healthString = "";
               String acString = "";
               
               switch (status) {
               case BatteryManager.BATTERY_STATUS_UNKNOWN:
                 statusString = "unknown";
                 break;
               case BatteryManager.BATTERY_STATUS_CHARGING:
                 statusString = "charging";
                 break;
               case BatteryManager.BATTERY_STATUS_DISCHARGING:
                 statusString = "discharging";
                 break;
               case BatteryManager.BATTERY_STATUS_NOT_CHARGING:
                 statusString = "not charging";
                 break;
               case BatteryManager.BATTERY_STATUS_FULL:
                 statusString = "full";
                 break;
               }
              
               switch (health) {
               case BatteryManager.BATTERY_HEALTH_UNKNOWN:
                 healthString = "unknown";
                 break;
               case BatteryManager.BATTERY_HEALTH_GOOD:
                 healthString = "good";
                 break;
               case BatteryManager.BATTERY_HEALTH_OVERHEAT:
                 healthString = "overheat";
                 break;
               case BatteryManager.BATTERY_HEALTH_DEAD:
                 healthString = "dead";
                 break;
               case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:
                 healthString = "voltage";
                 break;
               case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE:
                 healthString = "unspecified failure";
                 break;
               }
               
               
               switch (plugged) {
               case BatteryManager.BATTERY_PLUGGED_AC:
                 acString = "plugged ac";
                 break;
               case BatteryManager.BATTERY_PLUGGED_USB:
                 acString = "plugged usb";
                 break;
                default:
                 acString="";
                break;
               }                System.out.println("===1=>"+statusString);
               System.out.println("===2=>"+healthString);
               System.out.println("===3=>"+acString);
               
           } 
       } 
   };}
在线等公式呀也可以加我QQ研究研究：252339447