android天气预报widget----google开源天气API，SAX解析

 

 

转载请注明出处：

http://blog.csdn.net/dany1202/archive/2011/05/17/6426064.aspx

 

1.知识基础：小部件、数据库、SAX解析XML文件

2.实现说明：

   google提供了天气预报的开放XML文件

   http://www.google.com/ig/api?hl=zh-cn&weather=Beijing

   查看如上网址，会看到界面显示一个XML文件，用SAX解析的方式获取XML文件节点内容，并将其存储到一个实体当中。

   存储数据到数据库。

   显示内容到小部件。

3.窗口小部件时间的实时刷新

   Intent.ACTION_TIME_CHANGED 为系统时间每次发生改变的时候，发送的广播，其只能动态注册

   所以在小部件的WeatherWidgetProvider.java中的onUpdate()方法中开启service，并在service中进行注册接收的广播

  

 public class UpdateTimeService extends Service {
     BroadcastReceiver mIntentReceiver = new BroadcastReceiver(){
         @Override
         public void onReceive(Context context, Intent intent) {
             if(Intent.ACTION_TIMEZONE_CHANGED.equals(intent.getAction())
                     || Intent.ACTION_TIME_TICK.equals(intent.getAction())
                     || Intent.ACTION_TIME_CHANGED.equals(intent.getAction()))
             WeatherWidgetProvider.UpdateTime(context);

         }
     };

     @Override
     public void onDestroy() {
         unregisterReceiver(mIntentReceiver);
         super.onDestroy();
     }
     @Override
     public void onCreate() {
         IntentFilter commandFilter = new IntentFilter();
         commandFilter.addAction(Intent.ACTION_TIME_TICK);
         commandFilter.addAction(Intent.ACTION_TIME_CHANGED);
         commandFilter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
         getBaseContext().registerReceiver(mIntentReceiver, commandFilter);

         super.onCreate();
     }
     @Override
     public void onStart(Intent intent, int startId) {

         super.onStart(intent, startId);
     }
     @Override
     public IBinder onBind(Intent arg0) {

         return null;
     }
 }

   在WeatherWidgetProvider.java中提供静态方法public static void UpdateTime(Context context){。。。}刷新时间。

4.SAX解析，获取current_conditions节点内容

  

 public class XMLHandler extends DefaultHandler {
     private static final String TAG = "XMLHandler";
     private CurrentEntity currentWeather;
     private boolean currentFlag;

     public void setCurrentWeather(CurrentEntity currentWeather){
         this.currentWeather = currentWeather;
     }
     public CurrentEntity getCurrentWeather(){
         return currentWeather;
     }

     public XMLHandler() {
         currentFlag = false;
     }

     @Override
     public void startElement(String uri, String localName, String qName,
             Attributes attributes) throws SAXException {

         String tagName = localName.length() != 0 ? localName : qName;
         tagName = tagName.toLowerCase();

         Log.d(TAG,"tagName = "+tagName);
         if(tagName.equals("current_conditions")){
             currentFlag = true;
             currentWeather = new CurrentEntity();
         }

         if(currentFlag){
             if(tagName.equals("condition")){
                 Log.d(TAG,"condition = "+attributes.getValue("data"));
                 currentWeather.setCondition(attributes.getValue("data"));
             }else if(tagName.equals("temp_c")){
                 Log.d(TAG,"temp_c--------");
                 currentWeather.setTempc(attributes.getValue("data"));
             }else if(tagName.equals("humidity")){
                 currentWeather.setHumidity(attributes.getValue("data"));
             }else if(tagName.equals("icon")){
                 currentWeather.setIcon(attributes.getValue("data"));
             }else if(tagName.equals("wind_condition")){
                 currentWeather.setWindcondition(attributes.getValue("data"));
             }
         }


     }

     @Override
     public void endElement(String uri, String localName, String qName)
             throws SAXException {
         String tagName = localName.length() != 0 ? localName : qName;
         tagName = tagName.toLowerCase();

         if(tagName.equals("current_conditions")) {
             currentFlag = false;
         }
     }
 }

  将节点对应的内容存放到CurrentEntity实体类中。

5.在天气的service中，开启线程，刷新小部件中的天气内容

  

 public class UpdateForecastService extends Service implements Runnable {
     private static final String TAG = "UpdateForecastService";
     private Uri currentUri = null;
     private String city = "Beijing";
     @Override
     public IBinder onBind(Intent arg0) {
         // TODO Auto-generated method stub
         return null;
     }
     @Override
     public void onCreate() {

         super.onCreate();
     }
     @Override
     public void onDestroy() {
         // TODO Auto-generated method stub
         super.onDestroy();
     }
     @Override
     public void onStart(Intent intent, int startId) {
         super.onStart(intent, startId);

         currentUri = intent.getData();
         Cursor cur = getContentResolver().query(currentUri, null, Weathers._ID +"="+ currentUri.getPathSegments().get(1), null, null);

         if(cur!=null && cur.getCount()>0){
             cur.moveToFirst();
             city = cur.getString(2);
         }
         Log.d(TAG,"-----------city = "+city);

         new Thread(this).start();

     }

     public void run(){
         Log.d(TAG,"----------------run --------------");
         SAXParserFactory spf = SAXParserFactory.newInstance();

         try {
             SAXParser sp = spf.newSAXParser();
             XMLReader reader = sp.getXMLReader();

             XMLHandler  handler = new XMLHandler();
             reader.setContentHandler(handler);

             URL url = new URL(Weathers.WEB_URI + URLEncoder.encode(city));
             InputStream is = url.openStream();
             InputStreamReader isr = new InputStreamReader(is,"GBK");
             InputSource source = new InputSource(isr);

             reader.parse(source);

             CurrentEntity currentWeather = handler.getCurrentWeather();
             Log.d(TAG,"------tempc = "+currentWeather.getTempc()+"    condition = "+currentWeather.getCondition());

             ContentValues values = new ContentValues();
             values.put(Weathers.CONDITION, currentWeather.getCondition());
             values.put(Weathers.TEMPC,currentWeather.getTempc());
             values.put(Weathers.HUMIDITY,currentWeather.getHumidity());
             values.put(Weathers.ICON,currentWeather.getIcon());
             values.put(Weathers.WINDCONDITION,currentWeather.getWindcondition());

             getContentResolver().update(currentUri, values, null, null);

             WeatherWidgetProvider.UpdateWeather(this,currentUri);
         } catch (Exception e) {
             e.printStackTrace();
             Log.d(TAG,"not complete the parser");
         }


         stopSelf();
     }
 }

6小部件对应appwidgetprovider

 public class WeatherWidgetProvider extends AppWidgetProvider{
     private static final String TAG = "WeatherWidgetProvider";
     private static int flagsDate = DateUtils.FORMAT_SHOW_DATE;
     private static int flagsWeek = DateUtils.FORMAT_SHOW_WEEKDAY;

     @Override
     public void onUpdate(Context context, AppWidgetManager appWidgetManager,
             int[] appWidgetIds) {

         UpdateTime(context);
         Intent intent=new Intent(context ,UpdateTimeService.class);
         context.startService(intent);

         for(int i=0;i<appWidgetIds.length;i++){
             Cursor cur = context.getContentResolver().query(Weathers.CONTENT_URI,null,Weathers.WIDGETID+"="+appWidgetIds[i],null,null);
             if(cur!=null&& cur.getCount()>0){
                 cur.moveToFirst();
                 String uri = Weathers.CONTENT_URI+"/"+String.valueOf(cur.getString(0));
             Intent intentForcast = new Intent(context,UpdateForecastService.class);
             intentForcast.setData(Uri.parse(uri));
             context.startService(intentForcast);
             }
             cur.close();
         }

         super.onUpdate(context, appWidgetManager, appWidgetIds);
     }


     @Override
     public void onDeleted(Context context, int[] appWidgetIds) {
         if(0 == appWidgetIds.length){
             Intent intent = new Intent(context ,UpdateTimeService.class);
             context.stopService(intent);
         }
         super.onDeleted(context, appWidgetIds);
     }
     private final static String M12 = "h:mm";
     private final static String M24 = "kk:mm";
     public static void UpdateTime(Context context){
         RemoteViews views=new RemoteViews(context.getPackageName(),R.layout.weather_appwidget);
         String dateStr = (String)DateUtils.formatDateTime(context, System.currentTimeMillis(), flagsDate);
         String smPmStr = DateUtils.getAMPMString(Calendar.getInstance().get(Calendar.AM_PM));
         String formatTime;
         if(android.text.format.DateFormat.is24HourFormat(context)){
             formatTime = M24;
             views.setViewVisibility(R.id.widget_am_pm,View.GONE);
         }else{
             formatTime = M12;
             views.setViewVisibility(R.id.widget_am_pm,View.VISIBLE);
             views.setTextViewText(R.id.widget_am_pm, smPmStr);
         }
         String timeStr = (String) DateFormat.format(formatTime,System.currentTimeMillis());
         String weekStr = (String)DateUtils.formatDateTime(context, System.currentTimeMillis(), flagsWeek);

         views.setTextViewText(R.id.widget_date,dateStr+" "+weekStr);
         views.setTextViewText(R.id.widget_time,timeStr);

         AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
         int[] appWidgetIds=appWidgetManager.getAppWidgetIds(new  ComponentName(context, WeatherWidgetProvider.class));
         appWidgetManager.updateAppWidget(appWidgetIds, views);
     }
     public static void UpdateWeather(Context context, Uri currentUri) {
         Cursor curCurrent = context.getContentResolver().query(currentUri, null, Weathers._ID +"="+ currentUri.getPathSegments().get(1), null, null);
         if(curCurrent!=null && curCurrent.getCount()>0){
             curCurrent.moveToFirst();

             Log.d(TAG,"curCurrent.getInt(1) = "+curCurrent.getInt(1));
             Intent configIntent = new Intent(context, WeatherWidgetProvider.class);
             configIntent.setAction(currentUri.toString());
             configIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,curCurrent.getInt(1));
             PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0,configIntent, 0);

             RemoteViews views=new RemoteViews(context.getPackageName(),R.layout.weather_appwidget);
             views.setTextViewText(R.id.city,curCurrent.getString(2));
             views.setTextViewText(R.id.condition,curCurrent.getString(3));
             views.setTextViewText(R.id.tempc, curCurrent.getString(4)+"°");
             views.setTextViewText(R.id.humidity,curCurrent.getString(5));
             views.setImageViewResource(R.id.icon, WeatherUtil
                     .getForecastImage(curCurrent.getString(6)));

             views.setOnClickPendingIntent(R.id.icon, pendingIntent);

             AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
             appWidgetManager.updateAppWidget(curCurrent.getInt(1), views);
         }
         curCurrent.close();

     }
     @Override
     public void onReceive(Context context, Intent intent) {
         Log.d(TAG,"intent.getAction() = "+intent.getAction());
         if(intent.getAction().startsWith(Weathers.CONTENT_URI.toString())){
             int mAppWidgetId = intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
             Uri uri = Uri.parse(intent.getAction());
             Log.d(TAG,"mAppWidgetId = "+mAppWidgetId+"    uri = "+uri);

             Intent i = new Intent(context,UpdateForecastService.class);
             i.setData(uri);
             context.startService(i);
         }


         super.onReceive(context, intent);
     }
 }

 

在onUpdate中开启两个service，一个刷新时间，一个刷新天气。定义了一个Icon的点击事件，继续起到刷新天气的功能。

onReceive中接收点击事件，找到是哪一个小部件被点击了，根据小部件的Id进行区分。

当然此小部件是需要一个配置活动的，获取用户输入的城市名，不再多帖代码了，网上例子还是蛮多的

备注：搜狐天气api接口

http://sms.sohu.com/weatherfore/getformobile.php?city=北京