Android小挂件(APP Widgets)设计指导

<FrameLayout 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:padding="@dimen/widget_margin"> 
  
 <LinearLayout 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:orientation="horizontal" 
  android:background="@drawable/my_widget_background"> 
  
  <TextView 
   android:id="@+id/song_info" 
   android:layout_width="0dp" 
   android:layout_height="match_parent" 
   android:layout_weight="1" /> 
  
  <Button 
   android:id="@+id/play_button" 
   android:layout_width="@dimen/my_button_width" 
   android:layout_height="match_parent" /> 
  
  <Button 
   android:id="@+id/skip_button" 
   android:layout_width="@dimen/my_button_width" 
   android:layout_height="match_parent" /> 
 </LinearLayout> 
</FrameLayout> 

/* 
 * Copyright (C) 2009 The Android Open Source Project 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */ 
 
package com.example.android.wiktionary; 
 
import com.example.android.wiktionary.SimpleWikiHelper.ApiException; 
import com.example.android.wiktionary.SimpleWikiHelper.ParseException; 
 
import android.app.PendingIntent; 
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.content.res.Resources; 
import android.net.Uri; 
import android.os.IBinder; 
import android.text.format.Time; 
import android.util.Log; 
import android.widget.RemoteViews; 
 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
 
/** 
 * Define a simple widget that shows the Wiktionary "Word of the day." To build 
 * an update we spawn a background {@link Service} to perform the API queries. 
 */ 
public class WordWidget extends AppWidgetProvider { 
  /** 
   * Regular expression that splits "Word of the day" entry into word 
   * name, word type, and the first description bullet point. 
   */ 
  public static final String WOTD_PATTERN = 
    "(?s)\\{\\{wotd\\|(.+?)\\|(.+?)\\|([^#\\|]+).*?\\}\\}"; 
 
  @Override 
  public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { 
    Log.d("WordWidget.UpdateService", "onUpdate()"); 
    // To prevent any ANR timeouts, we perform the update in a service 
    context.startService(new Intent(context, UpdateService.class)); 
  } 
  public static class UpdateService extends Service { 
    @Override 
    public void onStart(Intent intent, int startId) { 
      Log.d("WordWidget.UpdateService", "onStart()"); 
 
      // Build the widget update for today 
      RemoteViews updateViews = buildUpdate(this); 
      Log.d("WordWidget.UpdateService", "update built"); 
       
      // Push update for this widget to the home screen 
      ComponentName thisWidget = new ComponentName(this, WordWidget.class); 
      AppWidgetManager manager = AppWidgetManager.getInstance(this); 
      manager.updateAppWidget(thisWidget, updateViews); 
      Log.d("WordWidget.UpdateService", "widget updated"); 
    } 
 
    @Override 
    public IBinder onBind(Intent intent) { 
      return null; 
    } 
    /** 
     * Build a widget update to show the current Wiktionary 
     * "Word of the day." Will block until the online API returns. 
     */ 
    public RemoteViews buildUpdate(Context context) { 
      // Pick out month names from resources 
      Resources res = context.getResources(); 
      String[] monthNames = res.getStringArray(R.array.month_names); 
       
      // Find current month and day 
      Time today = new Time(); 
      today.setToNow(); 
 
      // Build the page title for today, such as "March 21" 
      String pageName = res.getString(R.string.template_wotd_title, 
          monthNames[today.month], today.monthDay); 
      String pageContent = null; 
       
      try { 
        // Try querying the Wiktionary API for today's word 
        SimpleWikiHelper.prepareUserAgent(context); 
        pageContent = SimpleWikiHelper.getPageContent(pageName, false); 
      } catch (ApiException e) { 
        Log.e("WordWidget", "Couldn't contact API", e); 
      } catch (ParseException e) { 
        Log.e("WordWidget", "Couldn't parse API response", e); 
      } 
       
      RemoteViews views = null; 
      Matcher matcher = null; 
       
        Prefs prefs = new Prefs(this); 
      if (pageContent == null) { 
        // could not get content, use cache 
        // could be null 
        pageContent = prefs.getPageContent(); 
      } 
       
      if (pageContent != null) { 
        // we have page content 
        // is it valid? 
        matcher = Pattern.compile(WOTD_PATTERN).matcher(pageContent); 
      } 
      if (matcher != null && matcher.find()) { 
        // valid content, cache it  
        // ensure that latest valid content is 
        // always cached in case of failures 
        prefs.setPageContent(pageContent); 
 
        // Build an update that holds the updated widget contents 
        views = new RemoteViews(context.getPackageName(), R.layout.widget_word); 
         
        String wordTitle = matcher.group(1); 
        views.setTextViewText(R.id.word_title, wordTitle); 
        views.setTextViewText(R.id.word_type, matcher.group(2)); 
        views.setTextViewText(R.id.definition, matcher.group(3).trim()); 
         
        // When user clicks on widget, launch to Wiktionary definition page 
        String definePage = String.format("%s://%s/%s", ExtendedWikiHelper.WIKI_AUTHORITY, 
            ExtendedWikiHelper.WIKI_LOOKUP_HOST, wordTitle); 
        Intent defineIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(definePage)); 
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 
            0 /* no requestCode */, defineIntent, 0 /* no flags */); 
        views.setOnClickPendingIntent(R.id.widget, pendingIntent); 
         
      } else { 
        // Didn't find word of day, so show error message 
        views = new RemoteViews(context.getPackageName(), R.layout.widget_message); 
        views.setTextViewText(R.id.message, context.getString(R.string.widget_error)); 
      } 
      return views; 
    } 
  } 
}