The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...
/*
* Copyright (C) 2011 The Android开源工程
*
* 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.weatherlistwidget;
import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.content.Intent;
import android.content.ComponentName;
import android.content.ContentValues;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.database.Cursor;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Handler;
import android.os.HandlerThread;
import android.widget.RemoteViews;
import android.widget.Toast;
import java.util.Random;
/**
* Our data observer just notifies an update for all weather widgets when it detects a change.
*/
class WeatherDataProviderObserver extends ContentObserver {
private AppWidgetManager mAppWidgetManager;
private ComponentName mComponentName;
WeatherDataProviderObserver(AppWidgetManager mgr, ComponentName cn, Handler h) {
super(h);
mAppWidgetManager = mgr;
mComponentName = cn;
}
@Override
public void onChange(boolean selfChange) {
// The data has changed, so notify the widget that the collection view needs to be updated.
// In response, the factory's onDataSetChanged() will be called which will requery the
// cursor for the new data.
mAppWidgetManager.notifyAppWidgetViewDataChanged(
mAppWidgetManager.getAppWidgetIds(mComponentName), R.id.weather_list);
}
}
/**
* The weather widget's AppWidgetProvider.
*/
public class WeatherWidgetProvider extends AppWidgetProvider {
public static String CLICK_ACTION = "com.example.android.weatherlistwidget.CLICK";
public static String REFRESH_ACTION = "com.example.android.weatherlistwidget.REFRESH";
public static String EXTRA_CITY_ID = "com.example.android.weatherlistwidget.city";
private static HandlerThread sWorkerThread;
private static Handler sWorkerQueue;
private static WeatherDataProviderObserver sDataObserver;
public WeatherWidgetProvider() {
// Start the worker thread
sWorkerThread = new HandlerThread("WeatherWidgetProvider-worker");
sWorkerThread.start();
sWorkerQueue = new Handler(sWorkerThread.getLooper());
}
@Override
public void onEnabled(Context context) {
// Register for external updates to the data to trigger an update of the widget. When using
// content providers, the data is often updated via a background service, or in response to
// user interaction in the main app. To ensure that the widget always reflects the current
// state of the data, we must listen for changes and update ourselves accordingly.
final ContentResolver r = context.getContentResolver();
if (sDataObserver == null) {
final AppWidgetManager mgr = AppWidgetManager.getInstance(context);
final ComponentName cn = new ComponentName(context, WeatherWidgetProvider.class);
sDataObserver = new WeatherDataProviderObserver(mgr, cn, sWorkerQueue);
r.registerContentObserver(WeatherDataProvider.CONTENT_URI, true, sDataObserver);
}
}
@Override
public void onReceive(Context ctx, Intent intent) {
final String action = intent.getAction();
if (action.equals(REFRESH_ACTION)) {
// BroadcastReceivers have a limited amount of time to do work, so for this sample, we
// are triggering an update of the data on another thread. In practice, this update
// can be triggered from a background service, or perhaps as a result of user actions
// inside the main application.
final Context context = ctx;
sWorkerQueue.removeMessages(0);
sWorkerQueue.post(new Runnable() {
@Override
public void run() {
final ContentResolver r = context.getContentResolver();
final Cursor c = r.query(WeatherDataProvider.CONTENT_URI, null, null, null,
null);
final int count = c.getCount();
final int maxDegrees = 96;
// We disable the data changed observer temporarily since each of the updates
// will trigger an onChange() in our data observer.
r.unregisterContentObserver(sDataObserver);
for (int i = 0; i < count; ++i) {
final Uri uri = ContentUris.withAppendedId(WeatherDataProvider.CONTENT_URI, i);
final ContentValues values = new ContentValues();
values.put(WeatherDataProvider.Columns.TEMPERATURE,
new Random().nextInt(maxDegrees));
r.update(uri, values, null, null);
}
r.registerContentObserver(WeatherDataProvider.CONTENT_URI, true, sDataObserver);
final AppWidgetManager mgr = AppWidgetManager.getInstance(context);
final ComponentName cn = new ComponentName(context, WeatherWidgetProvider.class);
mgr.notifyAppWidgetViewDataChanged(mgr.getAppWidgetIds(cn), R.id.weather_list);
}
});
} else if (action.equals(CLICK_ACTION)) {
// Show a toast
final int appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
final String city = intent.getStringExtra(EXTRA_CITY_ID);
final String formatStr = ctx.getResources().getString(R.string.toast_format_string);
Toast.makeText(ctx, String.format(formatStr, city), Toast.LENGTH_SHORT).show();
}
super.onReceive(ctx, intent);
}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// Update each of the widgets with the remote adapter
for (int i = 0; i < appWidgetIds.length; ++i) {
// Specify the service to provide data for the collection widget. Note that we need to
// embed the appWidgetId via the data otherwise it will be ignored.
final Intent intent = new Intent(context, WeatherWidgetService.class);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]);
intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
final RemoteViews rv = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
rv.setRemoteAdapter(appWidgetIds[i], R.id.weather_list, intent);
// Set the empty view to be displayed if the collection is empty. It must be a sibling
// view of the collection view.
rv.setEmptyView(R.id.weather_list, R.id.empty_view);
// Bind a click listener template for the contents of the weather list. Note that we
// need to update the intent's data if we set an extra, since the extras will be
// ignored otherwise.
final Intent onClickIntent = new Intent(context, WeatherWidgetProvider.class);
onClickIntent.setAction(WeatherWidgetProvider.CLICK_ACTION);
onClickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]);
onClickIntent.setData(Uri.parse(onClickIntent.toUri(Intent.URI_INTENT_SCHEME)));
final PendingIntent onClickPendingIntent = PendingIntent.getBroadcast(context, 0,
onClickIntent, PendingIntent.FLAG_UPDATE_CURRENT);
rv.setPendingIntentTemplate(R.id.weather_list, onClickPendingIntent);
// Bind the click intent for the refresh button on the widget
final Intent refreshIntent = new Intent(context, WeatherWidgetProvider.class);
refreshIntent.setAction(WeatherWidgetProvider.REFRESH_ACTION);
final PendingIntent refreshPendingIntent = PendingIntent.getBroadcast(context, 0,
refreshIntent, PendingIntent.FLAG_UPDATE_CURRENT);
rv.setOnClickPendingIntent(R.id.refresh, refreshPendingIntent);
appWidgetManager.updateAppWidget(appWidgetIds[i], rv);
}
super.onUpdate(context, appWidgetManager, appWidgetIds);
}
}