关于安卓开发桌面小插件不自动更新的问题

Question

最近自己写一个安卓桌面的电子时钟程序，由于是新手，所以遇到了下面这个问题。
本应用是桌面电子时钟，虽然楼主将更新时间设置为1s，但这个桌面小时钟依然不能自动更新时间，代码如下：EX04_28.java
-----------------------------------------package com.android.ex04_28;import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;import android.app.Service;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
import android.widget.RemoteViews;public class EX04_28 extends AppWidgetProvider
{  @Override
  public void onUpdate(Context context, AppWidgetManager appWidgetManager,
      int[] appWidgetIds)
  {
    Intent intent = new Intent(context, UpdateService.class);
    context.startService(intent);   
  }  public static class UpdateService extends Service
  {    @Override
    public IBinder onBind(Intent arg0)
    {
      return null;
    }    @Override
    public void onStart(Intent intent, int startId)
    {
      RemoteViews updateViews = new RemoteViews(this.getPackageName(),
          R.layout.main);
      SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss",Locale.CHINA);
      updateViews.setTextViewText(R.id.TextView1, "" + sdf.format(new Date()));
      ComponentName thisWidget = new ComponentName(this, EX04_28.class);
      AppWidgetManager manager = AppWidgetManager.getInstance(this);
      manager.updateAppWidget(thisWidget, updateViews);    }
  }
}
main.xml
--------------------------------<?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"
  >
  <TextView 
    android:text="@+id/TextView1" 
    android:id="@+id/TextView1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:textColor="@android:color/black">
  </TextView>  
</LinearLayout>
strings.xml
-------------------------<?xml version="1.0" encoding="utf-8"?>
<resources>    <string name="app_name">EX04_28</string>
    <string name="action_settings">Settings</string>
    <string name="TextView1"></string></resources>
my_widget_provider.xml
---------------------------
<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
  android:minWidth="100dip"
  android:minHeight="100dip"
  android:updatePeriodMillis="1"
  android:initialLayout="@layout/main"
/>AndroidManifest.xml
---------------------------
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.ex04_28"
    android:versionCode="1"
    android:versionName="1.0" >    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.android.ex04_28.EX04_28"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>        <receiver
      android:label="@string/app_name"
      android:name=".EX04_28">
      <intent-filter>
        <action
          android:name="android.appwidget.action.APPWIDGET_UPDATE">
        </action>
      </intent-filter>
      <meta-data 
        android:resource="@xml/my_widget_provider" 
        android:name="android.appwidget.provider">
      </meta-data>
    </receiver>
    <service android:name=".EX04_28$UpdateService" />
  </application>
</manifest> Android应用