Android3.0自带天气例子

Android 3.0正式版API Level 11中加入了一个天气预报例子，下面是manifest.xml中的关键代码，只是少了xml的编码头:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.android.weatherlistwidget">    <uses-sdk android:minSdkVersion="11" />    <application android:label="Weather Widget Sample">         <receiver android:name="WeatherWidgetProvider">            <intent-filter>                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />            </intent-filter>                   <meta-data android:name="android.appwidget.provider"                    android:resource="@xml/widgetinfo" />        </receiver>         <service android:name="WeatherWidgetService"            android:permission="android.permission.BIND_REMOTEVIEWS"            android:exported="false" />         <provider android:name="WeatherDataProvider"              android:authorities="com.example.android.weatherlistwidget.provider" />    </application></manifest>

这里WeatherDataProvider.java的源码为主要是ContentProvider相关的处理，这里作为appWidget的receiver

  class WeatherDataPoint {    String city; //城市    int degrees; //度数    WeatherDataPoint(String c, int d) {        city = c;        degrees = d;    }} public class WeatherDataProvider extends ContentProvider {    public static final Uri CONTENT_URI =        Uri.parse("content://com.example.android.weatherlistwidget.provider");    public static class Columns {        public static final String ID = "_id";        public static final String CITY = "city";        public static final String TEMPERATURE = "temperature";    }     private static final ArrayList<WeatherDataPoint> sData = new ArrayList<WeatherDataPoint>();    @Override    public boolean onCreate() {        sData.add(new WeatherDataPoint("San Francisco", 13));        sData.add(new WeatherDataPoint("New York", 1));        sData.add(new WeatherDataPoint("Seattle", 7));        sData.add(new WeatherDataPoint("Boston", 4));        sData.add(new WeatherDataPoint("Miami", 22));        sData.add(new WeatherDataPoint("Toronto", -10));        sData.add(new WeatherDataPoint("Calgary", -13));        sData.add(new WeatherDataPoint("Tokyo", 8));        sData.add(new WeatherDataPoint("Kyoto", 11));        sData.add(new WeatherDataPoint("London", -1));        sData.add(new WeatherDataPoint("Nomanisan", 27));        return true;    }    @Override    public synchronized Cursor query(Uri uri, String[] projection, String selection,            String[] selectionArgs, String sortOrder) {        assert(uri.getPathSegments().isEmpty());         final MatrixCursor c = new MatrixCursor(                new String[]{ Columns.ID, Columns.CITY, Columns.TEMPERATURE });        for (int i = 0; i < sData.size(); ++i) {            final WeatherDataPoint data = sData.get(i);            c.addRow(new Object[]{ new Integer(i), data.city, new Integer(data.degrees) });        }        return c;    }    @Override    public String getType(Uri uri) {        return "vnd.android.cursor.dir/vnd.weatherlistwidget.citytemperature";    }    @Override    public Uri insert(Uri uri, ContentValues values) {        return null;    }    @Override    public int delete(Uri uri, String selection, String[] selectionArgs) {        return 0;    }    @Override    public synchronized int update(Uri uri, ContentValues values, String selection,            String[] selectionArgs) {        assert(uri.getPathSegments().size() == 1);        final int index = Integer.parseInt(uri.getPathSegments().get(0));        final MatrixCursor c = new MatrixCursor(                new String[]{ Columns.ID, Columns.CITY, Columns.TEMPERATURE });        assert(0 <= index && index < sData.size());        final WeatherDataPoint data = sData.get(index);        data.degrees = values.getAsInteger(Columns.TEMPERATURE);         getContext().getContentResolver().notifyChange(uri, null);        return 1;    }}

上面可以看到，对于插入和删除没有做过多的处理，对于天气更新给出了详细的解决方法。

有关 WeatherWidgetProvider.java 主要是appWidget的核心，为provider

class WeatherDataProviderObserver extends ContentObserver { //监控数据库的变化    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) {           mAppWidgetManager.notifyAppWidgetViewDataChanged(                mAppWidgetManager.getAppWidgetIds(mComponentName), R.id.weather_list);    }} 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() {         sWorkerThread = new HandlerThread("WeatherWidgetProvider-worker"); //开一个线程，这里用到了HandlerThread        sWorkerThread.start();        sWorkerQueue = new Handler(sWorkerThread.getLooper()); //不了解Thread的Looper可以看下这个例子比较简单清晰    }    @Override    public void onEnabled(Context context) { //当appWidget添加到桌面上时           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); //注册监控数据库变化的回调        }    }    @Override    public void onReceive(Context ctx, Intent intent) {        final String action = intent.getAction();        if (action.equals(REFRESH_ACTION)) { //接收数据库改变的回调广播               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;                    r.unregisterContentObserver(sDataObserver); //首先取消数据库监控                    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); //更新数据库记录层                    }                    r.registerContentObserver(WeatherDataProvider.CONTENT_URI, true, sDataObserver); //重新设置监视数据库                    final AppWidgetManager mgr = AppWidgetManager.getInstance(context);                    final ComponentName cn = new ComponentName(context, WeatherWidgetProvider.class);                    mgr.notifyAppWidgetViewDataChanged(mgr.getAppWidgetIds(cn), R.id.weather_list); //提示Widget有数据更新并刷新UI                }            });        } else if (action.equals(CLICK_ACTION)) {             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) {                 for (int i = 0; i < appWidgetIds.length; ++i) {                      final Intent intent = new Intent(context, WeatherWidgetService.class);   //当桌面上有多个这个相同的appWidget需要分别处理            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);            rv.setEmptyView(R.id.weather_list, R.id.empty_view);            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);            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);    }}

对于WeatherWidgetService.java这个Service集成于RemoteViewsService,主要是UI上的处理

public class WeatherWidgetService extends RemoteViewsService {    @Override    public RemoteViewsFactory onGetViewFactory(Intent intent) {        return new StackRemoteViewsFactory(this.getApplicationContext(), intent);    }}class StackRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory {    private Context mContext;    private Cursor mCursor;    private int mAppWidgetId;    public StackRemoteViewsFactory(Context context, Intent intent) {        mContext = context;        mAppWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,                AppWidgetManager.INVALID_APPWIDGET_ID);    }    public void onCreate() {    }    public void onDestroy() {        if (mCursor != null) {            mCursor.close();        }    }    public int getCount() {        return mCursor.getCount();    }    public RemoteViews getViewAt(int position) {        String city = "Unknown City";        int temp = 0;        if (mCursor.moveToPosition(position)) {            final int cityColIndex = mCursor.getColumnIndex(WeatherDataProvider.Columns.CITY);            final int tempColIndex = mCursor.getColumnIndex(                    WeatherDataProvider.Columns.TEMPERATURE);            city = mCursor.getString(cityColIndex);            temp = mCursor.getInt(tempColIndex);        }        final String formatStr = mContext.getResources().getString(R.string.item_format_string);        final int itemId = (position % 2 == 0 ? R.layout.light_widget_item                : R.layout.dark_widget_item);        RemoteViews rv = new RemoteViews(mContext.getPackageName(), itemId);        rv.setTextViewText(R.id.widget_item, String.format(formatStr, temp, city));        final Intent fillInIntent = new Intent();        final Bundle extras = new Bundle();        extras.putString(WeatherWidgetProvider.EXTRA_CITY_ID, city);        fillInIntent.putExtras(extras);        rv.setOnClickFillInIntent(R.id.widget_item, fillInIntent);        return rv;    }    public RemoteViews getLoadingView() {        return null;    }    public int getViewTypeCount() {        return 2;    }    public long getItemId(int position) {        return position;    }    public boolean hasStableIds() {        return true;    }    public void onDataSetChanged() {        if (mCursor != null) {            mCursor.close();        }        mCursor = mContext.getContentResolver().query(WeatherDataProvider.CONTENT_URI, null, null,                null, null);    }}

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