Android电池电量监控初步

鉴客 发布于 2012/01/29 11:03
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引言

,学习了包括Activity、Service、AppWidget、Broadcast、Intent、Notification、XML布局、XML配置等基础知识之后,尝试着做一个小玩意儿——电池监控,期间也是阻挠多多,现在基本完成了,所以把自己的经验分享给大家,希望能通过我的文章让还不会的朋友少走弯路,也算是这个小玩意儿的一点贡献。

假设读者已经具备并能基本使用上述基础知识,本文将只描述如何利用上述知识构建一个监控Android电池电量的小程序(若有相关知识不甚清楚,请查询Android SDK自带的document,官方文档是我们学习Android的一大利器),若有任何疑问或建议,欢迎留言提出,bill会很高兴和大家一起学习进步!

开发环境及Android平台版本

Android SDK 1.6及以上Android X86 虚拟机或真机

功能描述

自带的系统电池图标并不能显示当前电量,给不少用户带来了不便,所以本程序将对此进行改进,简单实现对Android手机电量的实时监控,并在左上角状态栏显示实时电池电量的通知图标,若正在充电,则显示充电状态。为方便起见,还为本程序制作了一个AppWidget,成为一个简单的桌面小工具。

效果预览

充电效果

整体思路概览

①由于要显示电池图标,因此需要一组对应的小icon,程序算出当前电量之后,就在状态栏上显示对应的icon即可。本程序用到的icon已经提供在附件,下载后将里面的icons直接复制到res\drawable-hdpi中即可。

②由于电池更新是一个长期存在的过程,因此需要将我们的程序注册为系统服务,以便长期生存于Android系统中。

③服务不会自行启动,因此我们需要为自己的服务创建一个Activity,在第一次启动本程序的Activity时创建并启动我们的监控服务,之后的事便交由服务处理,Activity暂时未有太大作用(之后还可以在Activity中显示电池当前的各种基本属性等等,本文不作介绍),当然,我们也可以不要Activity,直接将我们的服务设置为开机启动即可,关于开机启动的事项已在Android开机启动Activity或Service的方法】一文中详细描述,恕不赘述。

④为了方便起见,应该制作本程序的桌面小工具,也就用到了AppWidget方面的知识,稍后一一道来。

 

分而治之

小麻雀的心脏——电池监控服务MonitorService

ACTION_BATTERY_CHANGED

的完整代码,我会在可能费解的地方批注,希望能帮助大家理解。

    package com.billhoo.study;  
     
    import android.app.Notification;  //通知,即显示在屏幕左上角的小图标  
    import android.app.NotificationManager;  
    import android.app.PendingIntent;  
    import android.app.Service;  
    import android.content.BroadcastReceiver;  
    import android.content.Context;  
    import android.content.Intent;  
    import android.content.IntentFilter;  
    import android.os.BatteryManager;  
    import android.os.IBinder;  
     
    public class MonitorService extends Service {  
      @Override 
      public IBinder onBind(Intent intent) {  
        return null;  
      }  
     
      @Override 
      public void onStart(Intent intent, int startId) {  
        // 定义电池电量更新广播的过滤器,只接受带有ACTION_BATTERRY_CHANGED事件的Intent  
        IntentFilter batteryChangedReceiverFilter = new IntentFilter();  
        batteryChangedReceiverFilter.addAction(Intent.ACTION_BATTERY_CHANGED);  
          
        // 向系统注册batteryChangedReceiver接收器,本接收器的实现见代码字段处  
        registerReceiver(batteryChangedReceiver, batteryChangedReceiverFilter);  
     
        // 实例化Notification通知的管理器,即字段notification manager  
        notifyManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);  
     
        // 由于初始化本服务时系统可能没有发出ACTION_BATTERY_CHANGED广播,那么刚才注册的那个接收器将不会在本服务启动时被激活,这种情况下就无法显示当前电量,因此在这里添加一个匿名广播接收器。  
        new BroadcastReceiver() {  
          @Override 
          public void onReceive(Context context, Intent intent) {  
            int level = intent.getIntExtra("level", 0);  //电池电量等级  
            int scale = intent.getIntExtra("scale", 100);  //电池满时百分比  
            int status = intent.getIntExtra("status", 0);  //电池状态  
     
            // 若正在充电  
            if (status == BatteryManager.BATTERY_STATUS_CHARGING)  
              notification = getNotification(getChargingIcon(level * 100 / scale),  
                  "电池监控", System.currentTimeMillis(), "电池电量", "正在充电");  
            else 
              notification = getNotification(getStateIcon(level * 100 / scale),  
                  "电池监控", System.currentTimeMillis(), "电池电量", "请及时充电");  
          
        //向系统发送此通知,为方便起见,通知ID简单设为0  
            notifyManager.notify(0, notification);  
          }  
        };  
      }  
     
      @Override 
      public void onDestroy() {  
        //当本服务终止时,通过通知ID注销左上角的通知  
        notifyManager.cancel(0);  
      }  
     
      // --------------------------------------私有方法------------------------------  
      // 获得一个notification  
      private Notification getNotification(int notificationIcon, String tickerText,  
          long when, String contentTitle, String contentText) {  
        // 定义该notification的扩展文本和intent  
        Notification notification = new Notification(notificationIcon, tickerText,  
            when);  
        Context context = getApplicationContext();  
        Intent notificationIntent = new Intent(context, BatteryInfo.class);  
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0,  
            notificationIntent, 0);  
        notification.setLatestEventInfo(context, contentTitle, contentText,  
            contentIntent);  
     
        // 设置本状态出现在“正在进行”而非“通知”栏目,不允许用户清除状态图标  
        notification.flags |= Notification.FLAG_ONGOING_EVENT;  
        return notification;  
      }  
     
      // 获得对应的电池状态图标  
      private int getStateIcon(int batteryHealth) {  
        if (batteryHealth >= 0 || batteryHealth <= 100)  
          return batteryStateIcons[batteryHealth]; //这里是为了方便起见而硬编码的资源数组,直接从R.java文件中提取的十六进制资源ID  
        return R.drawable.stat_sys_battery_unknown;  
      }  
     
      // 获得对应的充电状态图标  
      private int getChargingIcon(int batteryHealth) {  
        if (batteryHealth >= 0 && batteryHealth < 5)  
          return R.drawable.stat_sys_battery_charge_anim0;  
        if (batteryHealth >= 5 && batteryHealth < 10)  
          return R.drawable.stat_sys_battery_charge_anim01;  
        if (batteryHealth >= 10 && batteryHealth < 15)  
          return R.drawable.stat_sys_battery_charge_anim02;  
        if (batteryHealth >= 15 && batteryHealth < 20)  
          return R.drawable.stat_sys_battery_charge_anim03;  
        if (batteryHealth >= 20 && batteryHealth < 25)  
          return R.drawable.stat_sys_battery_charge_anim04;  
        if (batteryHealth >= 25 && batteryHealth < 30)  
          return R.drawable.stat_sys_battery_charge_anim05;  
        if (batteryHealth >= 30 && batteryHealth < 35)  
          return R.drawable.stat_sys_battery_charge_anim06;  
        if (batteryHealth >= 35 && batteryHealth < 40)  
          return R.drawable.stat_sys_battery_charge_anim07;  
        if (batteryHealth >= 40 && batteryHealth < 45)  
          return R.drawable.stat_sys_battery_charge_anim08;  
        if (batteryHealth >= 45 && batteryHealth < 50)  
          return R.drawable.stat_sys_battery_charge_anim09;  
        if (batteryHealth >= 50 && batteryHealth < 55)  
          return R.drawable.stat_sys_battery_charge_anim10;  
        if (batteryHealth >= 55 && batteryHealth < 60)  
          return R.drawable.stat_sys_battery_charge_anim11;  
        if (batteryHealth >= 60 && batteryHealth < 65)  
          return R.drawable.stat_sys_battery_charge_anim12;  
        if (batteryHealth >= 65 && batteryHealth < 70)  
          return R.drawable.stat_sys_battery_charge_anim13;  
        if (batteryHealth >= 70 && batteryHealth < 75)  
          return R.drawable.stat_sys_battery_charge_anim14;  
        if (batteryHealth >= 75 && batteryHealth < 80)  
          return R.drawable.stat_sys_battery_charge_anim15;  
        if (batteryHealth >= 80 && batteryHealth < 85)  
          return R.drawable.stat_sys_battery_charge_anim16;  
        if (batteryHealth >= 85 && batteryHealth < 90)  
          return R.drawable.stat_sys_battery_charge_anim17;  
        if (batteryHealth >= 90 && batteryHealth < 95)  
          return R.drawable.stat_sys_battery_charge_anim18;  
        if (batteryHealth >= 95 && batteryHealth < 100)  
          return R.drawable.stat_sys_battery_charge_anim19;  
        if (batteryHealth == 100)  
          return R.drawable.stat_sys_battery_charge_animfull;  
        return R.drawable.stat_sys_battery_unknown;  
      }  
     
      // -------------------------------私有字段--------------------------------------  
      private NotificationManager notifyManager = null;  
      private Notification notification = null;  
     
      //这里是为了方便起见而硬编码的icon资源数组,直接从R.java文件中提取的十六进制资源ID,本数组的0号元素0x7f020002表示资源stat_sys_battery_0.png(见附件),以后累加。不同配置的ID可能不同,请读者自行修改。  
      private int batteryStateIcons[] = { 0x7f020002, 0x7f020003, 0x7f020004,  
          0x7f020005, 0x7f020006, 0x7f020007, 0x7f020008, 0x7f020009, 0x7f02000a,  
          0x7f02000b, 0x7f02000c, 0x7f02000d, 0x7f02000e, 0x7f02000f, 0x7f020010,  
          0x7f020011, 0x7f020012, 0x7f020013, 0x7f020014, 0x7f020015, 0x7f020016,  
          0x7f020017, 0x7f020018, 0x7f020019, 0x7f02001a, 0x7f02001b, 0x7f02001c,  
          0x7f02001d, 0x7f02001e, 0x7f02001f, 0x7f020020, 0x7f020021, 0x7f020022,  
          0x7f020023, 0x7f020024, 0x7f020025, 0x7f020026, 0x7f020027, 0x7f020028,  
          0x7f020029, 0x7f02002a, 0x7f02002b, 0x7f02002c, 0x7f02002d, 0x7f02002e,  
          0x7f02002f, 0x7f020030, 0x7f020031, 0x7f020032, 0x7f020033, 0x7f020034,  
          0x7f020035, 0x7f020036, 0x7f020037, 0x7f020038, 0x7f020039, 0x7f02003a,  
          0x7f02003b, 0x7f02003c, 0x7f02003d, 0x7f02003e, 0x7f02003f, 0x7f020040,  
          0x7f020041, 0x7f020042, 0x7f020043, 0x7f020044, 0x7f020045, 0x7f020046,  
          0x7f020047, 0x7f020048, 0x7f020049, 0x7f02004a, 0x7f02004b, 0x7f02004c,  
          0x7f02004d, 0x7f02004e, 0x7f02004f, 0x7f020050, 0x7f020051, 0x7f020052,  
          0x7f020053, 0x7f020054, 0x7f020055, 0x7f020056, 0x7f020057, 0x7f020058,  
          0x7f020059, 0x7f02005a, 0x7f02005b, 0x7f02005c, 0x7f02005d, 0x7f02005e,  
          0x7f02005f, 0x7f020060, 0x7f020061, 0x7f020062, 0x7f020063, 0x7f020064,  
          0x7f020065, 0x7f02007b };  
     
      // 接受电池信息更新的广播  
      private BroadcastReceiver batteryChangedReceiver = new BroadcastReceiver() {  
        public void onReceive(Context context, Intent intent) {  
          int level = intent.getIntExtra("level", 0);  
          int scale = intent.getIntExtra("scale", 100);  
          int status = intent.getIntExtra("status", 0);  
     
          // 若正在充电  
          if (status == BatteryManager.BATTERY_STATUS_CHARGING)  
            notification = getNotification(getChargingIcon(level * 100 / scale),  
                "Battery Monitor", System.currentTimeMillis(), "电池电量", "正在充电");  
          else 
            notification = getNotification(getStateIcon(level * 100 / scale),  
                "Battery Monitor", System.currentTimeMillis(), "电池电量", "请及时充电");  
          notifyManager.notify(0, notification);  
        }  
      };  
    } 

光有心,不跳怎么行?——BatteryMonitor

服务在系统配置文件中进行注册。

    <!-- service --> 
     <service android:name=".MonitorService" android:enabled="true" /> 

Bill的另一篇文章【Android开机启动Activity或Service的方法】),下面,我们将在一个Activity中启动MonitorService服务。

在AndroidManifest.xml中进行注册

    <!-- activity --> 
    <activity android:name=".BatteryMonitor" android:label="@string/battery_monitor_name"> 
        <intent-filter> 
        <action android:name="android.intent.action.MAIN" />   
        <category android:name="android.intent.category.LAUNCHER" /> 
        </intent-filter> 
    </activity> 

中编码启动我们的MonitorService服务即可
    package com.billhoo.study;  
     
    import android.app.Activity;  
    import android.content.Intent;  
    import android.os.Bundle;  
     
     
    public class BatteryMonitor extends Activity {  
      /** Called when the activity is first created. */ 
      @Override 
      public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
          
        //启动电池监控服务  
        startService(new Intent(this, MonitorService.class));  
      }  
    } 

,看看左上角是不是出现了一个小电池图标,并显示着当前电量?

 

麻雀虽小,五脏俱全——MonitorWidgetProvider 为麻雀穿上衣服

用户会将自己喜爱的小程序放在桌面以便快速启动,当然我们就不能放过这个机会!

还做不到这一点,难道我们应该期望用户在他的程序列表中长按我们的Activity,然后使出吃奶的劲儿把它扔在桌面上吗?不,他们通常长按桌面,然后轻点一个自己中意的Widget插件便能满足他们的需求。

,一来方便用户查看电池状态(仅凭左上角的通知有时候并不能满足用户的需求),二来方便用户随时启动本程序附带的电池详细数据报告(本功能并未在本文中实现)。

本身就是一个广播接收器(BroadcastReceiver),因此我们最初企图直接用这个Widget接受ACTION_BATTERY_CHANGED广播并作出反应,但却发现这个接收器并不会接受电池更新的广播(不论我们在配置文件中配置与否)。所以只能另寻出路,我们想到,可以使用一个单独的为本Widget服务的Service,该Service检测到电池电量更新后就更新桌面的Widget显示。于是便有以下Widget及其配套Service的实现。

创建一个配置文件,用于描述本Widget在桌面显示时是个什么样子。

    <!-- 项目路径\res\layout\monitor_widget_layout.xml -->   
    <?xml version="1.0" encoding="utf-8"?> 
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   
        android:orientation="vertical" 
        android:layout_width="72dip" 
        android:layout_height="72dip"> 
        <ImageView android:id="@+id/monitor_widget_view" 
         android:layout_width="fill_parent" 
        android:layout_height="fill_parent"
        android:src="@drawable/vertical_battery_unknown" /> 
     </LinearLayout> 

    <!-- 项目路径\res\xml\monitor_widget_info.xml (xml文件夹是自行创建的)--> 
    <?xml version="1.0" encoding="utf-8"?> 
    <appwidget-providerxmlns:androidappwidget-providerxmlns:android="http://schemas.android.com/apk/res/android"               android:initialLayout="@layout/monitor_widget_layout" 
    android:minWidth="72dip" android:minHeight="72dip" /> 
配置文件中注册我们的Widget

    <receiver android:name=".MonitorWidgetProvider">
    <intent-filter> 
    <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> 
    <action android:name="android.intent.action.BATTERY_CHANGED" /> 
    </intent-filter> 
    <meta-data android:name="android.appwidget.provider" 
      android:resource="@xml/monitor_widget_info" /> 
    </receiver> 

的实现代码
    package com.billhoo.study;  
     
    import android.appwidget.AppWidgetManager;  
    import android.appwidget.AppWidgetProvider;  
    import android.content.Context;  
    import android.content.Intent;  
     
    public class MonitorWidgetProvider extends AppWidgetProvider   
    {  
      //当Widget第一次被启动时,启动配套服务  
      @Override 
      public void onEnabled(Context context) {  
        context.startService(new Intent(context,   
     
    WidgetUpdateService.class));  
      }  
     
      //当Widget更新时,启动配套服务  
      @Override 
      public void onUpdate(Context context, AppWidgetManager   
     
    appWidgetManager,  
          int appWidgetIds[]) {  
        super.onUpdate(context, appWidgetManager, appWidgetIds);  
        context.startService(new Intent(context,   
     
    WidgetUpdateService.class));  
      }  
     
      // 当桌面上这个widget的所有实体都被删除后,停止配套服务  
      @Override 
      public void onDisabled(Context context) {  
        context.stopService(new Intent(context, WidgetUpdateService.class));  
      }  
    } 

编写配套的Service。

中注册这个服务。

<service android:name=".WidgetUpdateService" android:enabled="true" />

然后编写Java 代码:

    package com.billhoo.study;  
     
    import android.app.Service;  
    import android.appwidget.AppWidgetManager;  
    import android.content.BroadcastReceiver;  
    import android.content.ComponentName;  
    import android.content.Context;  
    import android.content.Intent;  
    import android.content.IntentFilter;  
    import android.os.BatteryManager;  
    import android.os.IBinder;  
    import android.widget.RemoteViews;  
     
    //用以根据电池电量更新而刷新桌面Widget的服务  
    public class WidgetUpdateService extends Service {  
      @Override 
      public IBinder onBind(Intent intent) {  
        return null;  
      }  
     
      @Override 
      public void onStart(Intent intent, int startId) {  
        // 向系统注册电池电量更新广播,只接受带有ACTION_BATTERRY_CHANGED事件的Intent  
        registerReceiver(this.bCR, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));  
     
        bCR = new BroadcastReceiver() {  
          @Override 
          public void onReceive(Context context, Intent intent) {  
            int level = intent.getIntExtra("level", 0);  
            int scale = intent.getIntExtra("scale", 100);  
            int status = intent.getIntExtra("status", 0);  
            int batteryHealth = level * 100 / scale;  
            int icon = 0;  
     
            AppWidgetManager widgetManager = AppWidgetManager.getInstance(context);  
            RemoteViews widgetView = new RemoteViews(context.getPackageName(),  
                R.layout.monitor_widget_layout);  
     
            // 若正在充电  
            if (status == BatteryManager.BATTERY_STATUS_CHARGING) {  
              icon = getChargingIcon(batteryHealth);  
              widgetView.setImageViewResource(R.id.monitor_widget_view, icon  
     
              );  
            } else 
              widgetView.setImageViewResource(R.id.monitor_widget_view,  
                  getStateIcon(batteryHealth));  
            widgetManager.updateAppWidget(new ComponentName(context,  
                MonitorWidgetProvider.class), widgetView);  
          }  
        };  
      }  
     
      private BroadcastReceiver bCR = null;  
     
      // 获取电池状态图标  
      private int getStateIcon(int batteryHealth) {  
        if (batteryHealth >= 0 || batteryHealth <= 100)  
          return batteryStateIcon[batteryHealth / 5];  
        return R.drawable.vertical_battery_unknown;  
      }  
     
      // 获得对应的充电状态图标  
      private int getChargingIcon(int batteryHealth) {  
        if (batteryHealth >= 0 && batteryHealth < 5)  
          return R.drawable.vertical_charging_00;  
        if (batteryHealth >= 5 && batteryHealth < 10)  
          return R.drawable.vertical_charging_01;  
        if (batteryHealth >= 10 && batteryHealth < 15)  
          return R.drawable.vertical_charging_02;  
        if (batteryHealth >= 15 && batteryHealth < 20)  
          return R.drawable.vertical_charging_03;  
        if (batteryHealth >= 20 && batteryHealth < 25)  
          return R.drawable.vertical_charging_04;  
        if (batteryHealth >= 25 && batteryHealth < 30)  
          return R.drawable.vertical_charging_05;  
        if (batteryHealth >= 30 && batteryHealth < 35)  
          return R.drawable.vertical_charging_06;  
        if (batteryHealth >= 35 && batteryHealth < 40)  
          return R.drawable.vertical_charging_07;  
        if (batteryHealth >= 40 && batteryHealth < 45)  
          return R.drawable.vertical_charging_08;  
        if (batteryHealth >= 45 && batteryHealth < 50)  
          return R.drawable.vertical_charging_09;  
        if (batteryHealth >= 50 && batteryHealth < 55)  
          return R.drawable.vertical_charging_10;  
        if (batteryHealth >= 55 && batteryHealth < 60)  
          return R.drawable.vertical_charging_11;  
        if (batteryHealth >= 60 && batteryHealth < 65)  
          return R.drawable.vertical_charging_12;  
        if (batteryHealth >= 65 && batteryHealth < 70)  
          return R.drawable.vertical_charging_13;  
        if (batteryHealth >= 70 && batteryHealth < 75)  
          return R.drawable.vertical_charging_14;  
        if (batteryHealth >= 75 && batteryHealth < 80)  
          return R.drawable.vertical_charging_15;  
        if (batteryHealth >= 80 && batteryHealth < 85)  
          return R.drawable.vertical_charging_16;  
        if (batteryHealth >= 85 && batteryHealth < 90)  
          return R.drawable.vertical_charging_17;  
        if (batteryHealth >= 90 && batteryHealth < 95)  
          return R.drawable.vertical_charging_18;  
        if (batteryHealth >= 95 && batteryHealth < 100)  
          return R.drawable.vertical_charging_19;  
        if (batteryHealth == 100)  
          return R.drawable.vertical_battery_full;  
        return R.drawable.stat_sys_battery_unknown;  
      }  
     
      private int batteryStateIcon[] = { 0x7f02007d, 0x7f02007e, 0x7f02007f,  
          0x7f020080, 0x7f020081, 0x7f020082, 0x7f020083, 0x7f020084, 0x7f020085,  
          0x7f020086, 0x7f020087, 0x7f020088, 0x7f020089, 0x7f02008a, 0x7f02008b,  
          0x7f02008c, 0x7f02008d, 0x7f02008e, 0x7f02008f, 0x7f020090, 0x7f020091 };  
    } 

自带的电池图标了,何乐不为?

让麻雀自食其力——开机启动

已经在 Android 开机启动 Activity Service 的方法】一文中详述,故恕我不再赘述。

写在最后

电池监控程序来不断完善自己的小玩意儿,在完善的过程中,就是一次对自己的历练。

http://billhoo.blog.51cto.com/2337751/762776

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jeffsui
jeffsui
收藏了,思路不错!
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