android天气预报----google开源天气API，SAX解析

最近项目不太忙，就抽空看了看天气预报，做个玩玩，上图：

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