按照坛友的教程改了一下。

教程:http://billhoo.blog.51cto.com/2337751/762776
AppWidget系统框架:http://blog.csdn.net/thl789/article/details/7879257

WidgetUpdateService.java
package com.hy.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];
        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 < 10)
            return R.drawable.stat_sys_battery_charge_anim5;
        if (batteryHealth >= 10 && batteryHealth < 20)
            return R.drawable.stat_sys_battery_charge_anim15;
        if (batteryHealth >= 20 && batteryHealth < 30)
            return R.drawable.stat_sys_battery_charge_anim25;
        if (batteryHealth >= 30 && batteryHealth < 40)
            return R.drawable.stat_sys_battery_charge_anim35;
        if (batteryHealth >= 40 && batteryHealth < 50)
            return R.drawable.stat_sys_battery_charge_anim45;
        if (batteryHealth >= 50 && batteryHealth < 60)
            return R.drawable.stat_sys_battery_charge_anim55;
        if (batteryHealth >= 60 && batteryHealth < 70)
            return R.drawable.stat_sys_battery_charge_anim65;
        if (batteryHealth >= 70 && batteryHealth < 80)
            return R.drawable.stat_sys_battery_charge_anim75;
        if (batteryHealth >= 80 && batteryHealth < 90)
            return R.drawable.stat_sys_battery_charge_anim85;
        if (batteryHealth >= 90 && batteryHealth < 100)
            return R.drawable.stat_sys_battery_charge_anim95;
        if (batteryHealth == 100)
            return R.drawable.stat_sys_battery_charge_animfull;
        return R.drawable.stat_sys_battery_unknown;
    }

    private int batteryStateIcon[] = { R.drawable.stat_sys_battery_0,
            R.drawable.stat_sys_battery_1, R.drawable.stat_sys_battery_2,
            R.drawable.stat_sys_battery_3, R.drawable.stat_sys_battery_4,
            R.drawable.stat_sys_battery_5, R.drawable.stat_sys_battery_6,
            R.drawable.stat_sys_battery_7, R.drawable.stat_sys_battery_8,
            R.drawable.stat_sys_battery_9, R.drawable.stat_sys_battery_10,
            R.drawable.stat_sys_battery_11, R.drawable.stat_sys_battery_12,
            R.drawable.stat_sys_battery_13, R.drawable.stat_sys_battery_14,
            R.drawable.stat_sys_battery_15, R.drawable.stat_sys_battery_16,
            R.drawable.stat_sys_battery_17, R.drawable.stat_sys_battery_18,
            R.drawable.stat_sys_battery_19, R.drawable.stat_sys_battery_20,
            R.drawable.stat_sys_battery_21, R.drawable.stat_sys_battery_22,
            R.drawable.stat_sys_battery_23, R.drawable.stat_sys_battery_24,
            R.drawable.stat_sys_battery_25, R.drawable.stat_sys_battery_26,
            R.drawable.stat_sys_battery_27, R.drawable.stat_sys_battery_28,
            R.drawable.stat_sys_battery_29, R.drawable.stat_sys_battery_30,
            R.drawable.stat_sys_battery_31, R.drawable.stat_sys_battery_32,
            R.drawable.stat_sys_battery_33, R.drawable.stat_sys_battery_34,
            R.drawable.stat_sys_battery_35, R.drawable.stat_sys_battery_36,
            R.drawable.stat_sys_battery_37, R.drawable.stat_sys_battery_38,
            R.drawable.stat_sys_battery_39, R.drawable.stat_sys_battery_40,
            R.drawable.stat_sys_battery_41, R.drawable.stat_sys_battery_42,
            R.drawable.stat_sys_battery_43, R.drawable.stat_sys_battery_44,
            R.drawable.stat_sys_battery_45, R.drawable.stat_sys_battery_46,
            R.drawable.stat_sys_battery_47, R.drawable.stat_sys_battery_48,
            R.drawable.stat_sys_battery_49, R.drawable.stat_sys_battery_50,
            R.drawable.stat_sys_battery_51, R.drawable.stat_sys_battery_52,
            R.drawable.stat_sys_battery_53, R.drawable.stat_sys_battery_54,
            R.drawable.stat_sys_battery_55, R.drawable.stat_sys_battery_56,
            R.drawable.stat_sys_battery_57, R.drawable.stat_sys_battery_58,
            R.drawable.stat_sys_battery_59, R.drawable.stat_sys_battery_60,
            R.drawable.stat_sys_battery_61, R.drawable.stat_sys_battery_62,
            R.drawable.stat_sys_battery_63, R.drawable.stat_sys_battery_64,
            R.drawable.stat_sys_battery_65, R.drawable.stat_sys_battery_66,
            R.drawable.stat_sys_battery_67, R.drawable.stat_sys_battery_68,
            R.drawable.stat_sys_battery_69, R.drawable.stat_sys_battery_70,
            R.drawable.stat_sys_battery_71, R.drawable.stat_sys_battery_72,
            R.drawable.stat_sys_battery_73, R.drawable.stat_sys_battery_74,
            R.drawable.stat_sys_battery_75, R.drawable.stat_sys_battery_76,
            R.drawable.stat_sys_battery_77, R.drawable.stat_sys_battery_78,
            R.drawable.stat_sys_battery_79, R.drawable.stat_sys_battery_80,
            R.drawable.stat_sys_battery_81, R.drawable.stat_sys_battery_82,
            R.drawable.stat_sys_battery_83, R.drawable.stat_sys_battery_84,
            R.drawable.stat_sys_battery_85, R.drawable.stat_sys_battery_86,
            R.drawable.stat_sys_battery_87, R.drawable.stat_sys_battery_88,
            R.drawable.stat_sys_battery_89, R.drawable.stat_sys_battery_90,
            R.drawable.stat_sys_battery_91, R.drawable.stat_sys_battery_92,
            R.drawable.stat_sys_battery_93, R.drawable.stat_sys_battery_94,
            R.drawable.stat_sys_battery_95, R.drawable.stat_sys_battery_96,
            R.drawable.stat_sys_battery_97, R.drawable.stat_sys_battery_98,
            R.drawable.stat_sys_battery_99, R.drawable.stat_sys_battery_100 };
}

-------------------------------------------------------------------------------------------
BatteryMonitor.java
package com.hy.study;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class BatteryMonitor extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startService(new Intent(this, WidgetUpdateService.class));
    }
}

-------------------------------------------------------------------------------------------
MonitorWidgetProvider.java
package com.hy.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));
    }
}


-------------------------------------------------------------------------------------------
res\layout\monitor_widget_layout.xml

    android:orientation="vertical"
    android:layout_width="72dip"
    android:layout_height="72dip">
         android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:src="@drawable/stat_sys_battery_unknown" />
 


-------------------------------------------------------------------------------------------
res\xml\monitor_widget_info.xml

   android:minWidth="294dp"
   android:minHeight="72dp"
   android:updatePeriodMillis="1000"
   android:initialLayout="@layout/monitor_widget_layout"
/>

-------------------------------------------------------------------------------------------
AndroidManifest.xml

    package="com.hy.study"
    android:versionCode="1"
    android:versionName="1.0" >
            android:minSdkVersion="8"
        android:targetSdkVersion="10" />
            android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
                    android:name="com.hy.study.BatteryMonitor"
            android:label="@string/app_name"
            android:launchMode="singleTask" >
       
                    android:name=".WidgetUpdateService"
            android:enabled="true" />
       
           
               
               
           

                            android:name="android.appwidget.provider"
                android:resource="@xml/monitor_widget_info" />
       

   


安卓电量Widget_第1张图片