Source

weather.xhtml

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
	xmlns:h="http://java.sun.com/jsf/html"
	xmlns:f="http://java.sun.com/jsf/core"
	xmlns:p="http://primefaces.org/ui"
    xmlns:pm="http://primefaces.org/mobile">
    
    <f:view renderKitId="PRIMEFACES_MOBILE" />
    
    <h:head>

    </h:head>
    
    <h:body>
        
        <pm:page id="main">
            <pm:header title="Weather" swatch="b">
                <p:button styleClass="ui-toolbar-header-button-right ui-button-inline" value="Settings" icon="ui-icon-gear" outcome="pm:settings" />
            </pm:header>
            
            <pm:content>
                
                <h:form id="mainForm">
                    <pm:field>
                        <p:outputLabel for="city" value="Select City:" />
                        <p:selectOneMenu id="city" value="#{weatherView.city}">
                            <f:selectItems value="#{weatherView.cities}" />
                        </p:selectOneMenu>
                    </pm:field>

                    <p:commandButton value="Get Forecast" update="display" actionListener="#{weatherView.retrieveConditions}"/>

                    <p:outputPanel id="display" style="text-align:center">
                        <h:outputText value="#{weatherView.conditions}" escape="false" />
                    </p:outputPanel>
                </h:form>
                
            </pm:content>
        </pm:page>
        
        <pm:page id="settings">
            <pm:header title="Settings" swatch="b">
                <p:button styleClass="ui-toolbar-header-button-left ui-button-inline" value="Back" icon="ui-icon-arrow-l" outcome="pm:main" />
            </pm:header>
            
            <pm:content>
                
                <h:form id="settingsForm">
                    <pm:field>
                        <p:outputLabel for="unit" value="Unit:" />
                        <p:selectOneMenu id="unit" value="#{weatherView.unit}">
                            <f:selectItem itemLabel="Celcius" itemValue="c" />
                            <f:selectItem itemLabel="Fahrenheit" itemValue="f" />
                        </p:selectOneMenu>
                    </pm:field>

                    <p:commandButton value="Save" action="#{weatherView.saveSettings}"/>
                </h:form>
                
            </pm:content>
        </pm:page>
    </h:body>
    
</html>

WeatherView.java

package org.primefaces.showcase.mobile;

import com.sun.syndication.feed.synd.SyndEntry;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.io.SyndFeedInput;
import com.sun.syndication.io.XmlReader;
import java.io.Serializable;
import java.net.URL;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.logging.Logger;
import javax.annotation.PostConstruct;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;

@ManagedBean
@ViewScoped
public class WeatherView implements Serializable {

	private String conditions;
	private String city;
	private String unit = "c";
    private Map<String,String> cities;
    
    private static final Logger logger = Logger.getLogger(WeatherView.class.getName());

    @PostConstruct
    public void init() {
        cities = new LinkedHashMap<String, String>();
        cities.put("Istanbul", "TUXX0014");
        cities.put("Barcelona", "SPXX0015");
        cities.put("London", "UKXX0085");
        cities.put("New York", "USNY0996");
        cities.put("Paris", "FRXX2071");
        cities.put("Rome", "ITXX0067");
    }

	public String getCity() {
		return city;
	}
	public void setCity(String city) {
		this.city = city;
	}

	public String getConditions() {
		return conditions;
	}
	public void setConditions(String conditions) {
		this.conditions = conditions;
	}
		
	public String getUnit() {
		return unit;
	}
	public void setUnit(String unit) {
		this.unit = unit;
	}

    public Map<String, String> getCities() {
        return cities;
    }

    public void retrieveConditions() {
        try {
			URL feedSource = new URL("http://weather.yahooapis.com/forecastrss?p=" + city + "&u=" + unit);
			SyndFeedInput input = new SyndFeedInput();
			SyndFeed feed = input.build(new XmlReader(feedSource));
			String value = ((SyndEntry) feed.getEntries().get(0)).getDescription().getValue();
			
			conditions = value.split("<a href")[0];
		} catch (Exception e) {
			logger.severe(e.getMessage());
            conditions = "Unable to retrieve weather forecast at the moment.";
		}
	}

    public String saveSettings() {
        conditions = null;
        return "pm:main";
    }
}