爲什麼小部件不更新？

Question

當處於充電狀態時，我無法更新小部件。電池電量保持不變。我的代碼有什麼問題？

public class BatteryStatusWidgetActivity extends AppWidgetProvider { 
    /** Called when the activity is first created. */ 
    private String batteryLevel = "init"; 
    private String temperatura = "init"; 
    private int widgetImageFrame = R.drawable.full; 

    @Override 
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, 
      int[] appWidgetIds) { 
     context.getApplicationContext().registerReceiver(this, 
       new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 
     updateView(context); 
    } 

    @Override 
    public void onReceive(Context context, Intent intent) { 
     if (intent.getAction().contentEquals(
       "com.sec.android.widgetapp.APPWIDGET_RESIZE") 
       || intent.getAction().equals(
         "android.appwidget.action.APPWIDGET_UPDATE_OPTIONS")) { 
     } else { 
      int rawlevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1); 
      int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1); 
      int level = -1; 
      level = (rawlevel * 100)/scale; 
      batteryLevel = level + "%"; 
      // temperatura 
      int temperature = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE, 
        -1)/10; 
      temperatura = temperature + "°C"; 
      widgetImageFrame = R.drawable.full; 
      updateView(context); 
     } 
     super.onReceive(context, intent); 
    } 

    public void updateView(Context context) { 
     RemoteViews thisViews = new RemoteViews(context.getApplicationContext() 
       .getPackageName(), R.layout.widget_layout); 
     thisViews.setTextViewText(R.id.widget_text, batteryLevel + " | " 
       + temperatura); 
     thisViews.setImageViewResource(R.id.imageView1, widgetImageFrame); 
     ComponentName thisWidget = new ComponentName(context, 
       BatteryStatusWidgetActivity.class); 
     AppWidgetManager.getInstance(context).updateAppWidget(thisWidget, 
       thisViews); 
    } 
} 

這是最主要的部件

<?xml version="1.0" encoding="utf-8" ?> 
    <appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android" android:initialLayout="@layout/widget_layout" android:minWidth="40dp" android:minHeight="40dp" android:updatePeriodMillis="3000" /> 

那麼是什麼問題呢？ android:updatePeriodMillis="3000"？

Answer 1

updatePeriodMillis屬性定義App Widget框架通過調用onUpdate()回調方法應該從AppWidgetProvider請求更新的頻率。

from http://developer.android.com/guide/topics/appwidgets/index.html#MetaData