How to place markers on google map

Question

I use the google map tool from primefaces. I want my user to be able to place just one marker on a map. The values of the coordinates should be stored in a managed bean variables.

How can I do that? See what I did so far:

I created the map:

    <f:view contentType="text/html">
            <p:gmap id="gmap" center="36.890257,30.707417" zoom="13" type="HYBRID"   
    style="width:600px;height:400px"  
    model="#{mapBean.emptyModel}"   
    onPointClick="handlePointClick(event);"   
    widgetVar="map" />  </f:view>

<p:dialog widgetVar="dlg" effect="FADE" effectDuration="0.5" close="false" fixedCenter="true">  
    <h:form prependId="false">  
        <h:panelGrid columns="2">  
            <h:outputLabel for="title" value="Title:" />  
            <p:inputText id="title" value="#{mapBean.title}" />  

            <f:facet name="footer">  
                <p:commandButton value="Add"   
                        actionListener="#{mapBean.addMarker}"   
                        update="messages"   
                        oncomplete="markerAddComplete()"/>  
                <p:commandButton value="Cancel" onclick="return cancel()"/>  
            </f:facet>  
        </h:panelGrid>  

        <h:inputHidden id="lat" value="#{newOfferSupportController.mapLocationX}" />  
        <h:inputHidden id="lng" value="#{newOfferSupportController.mapLocationY}" />  
    </h:form>  
</p:dialog>  

<script type="text/javascript">  
    var currentMarker = null;  

    function handlePointClick(event) {  
        if(currentMarker == null) {  
            document.getElementById('lat').value = event.latLng.lat();  
            document.getElementById('lng').value = event.latLng.lng();  

            currentMarker = new google.maps.Marker({  
                position:new google.maps.LatLng(event.latLng.lat(), event.latLng.lng())  
            });  

            map.addOverlay(currentMarker);  

            dlg.show();  
        }     
    }  

    function markerAddComplete() {  
        var title = document.getElementById('title');  
        currentMarker.setTitle(title.value);  
        title.value = "";  

        currentMarker = null;  
        dlg.hide();  
    }  

    function cancel() {  
        dlg.hide();  
        currentMarker.setMap(null);  
        currentMarker = null;  

        return false;  
    }  
</script>

I also greated the variables that will hold the coordinates:

@ManagedBean
@RequestScoped
public class NewOfferSupportController {

private float mapLocationX;
private float mapLocationY;

//Get & set methods

It all works as in the primefaces page but I have 2 problems:

Problem 1: Once the marker is placed, it cannot be placed again.

Problem 2: In the same form where the map is there are some other elements such as text fields. I noticed that validation does not occur when I click on the submit button located in the form where the map is, Actually the form does not get submitted at all(This didn't occur before i added the map), why is the map disrupting the validation?

Answer 1

Problem 1: Once the marker is placed, it cannot be placed again.

This problem is caused by the following things:

1. You've bound latitude and longitude to a different bean (NewOfferSupportController) than the bean which holds the map model (MapBean). You should be using MapBean example in the PrimeFaces showcase as design starting point for NewOfferSupportController bean. It namely stores the markers set. The hidden inputs must point to that bean because in the addMarker() method those values will be added. From the showcase example you just have to rename the MapBean class name and rename #{mapBean} references in the view by #{newOfferSupportController}.

2. Your NewOfferSupportController bean is request scoped while it should be view scoped.

   @ManagedBean
   @ViewScoped
   public class NewOfferSupportController implements Serializable {}
   

   View scoped beans live as long as you're interacting with the same form by Ajax. But request scoped beans get recreated on every request (and thus also on every Ajax request!), hereby trashing the markers which are placed before in the map and inputs which are entered before adding markers.

---

Problem 2: In the same form where the map is there are some other elements such as text fields. Actually the form does not get submitted at all(This didn't occur before i added the map), why is the map disrupting the validation?

This works for me. This is likely caused because your NewOfferSupportController is been placed in the request scope instead of the view scope.

To recap, here is the code which I used in my test:

view:

<p:growl id="messages" showDetail="true" />  

<h:form>
    <p:gmap id="gmap" center="36.890257,30.707417" zoom="13" type="HYBRID" style="width:600px;height:400px"  
        model="#{mapBean.mapModel}" onPointClick="handlePointClick(event);" widgetVar="map" />
    <h:inputText value="#{mapBean.input}" required="true" />
    <p:commandButton value="submit" action="#{mapBean.submit}" update="messages" />
</h:form>

<p:dialog widgetVar="dlg" effect="FADE" effectDuration="0.5" close="false" fixedCenter="true">  
    <h:form prependId="false">  
        <h:panelGrid columns="2">  
            <h:outputLabel for="title" value="Title:" />  
            <p:inputText id="title" value="#{mapBean.title}" />  

            <f:facet name="footer">  
                <p:commandButton value="Add" actionListener="#{mapBean.addMarker}"   
                    update="messages" oncomplete="markerAddComplete()"/>  
                <p:commandButton value="Cancel" onclick="return cancel()"/>  
            </f:facet>
        </h:panelGrid>

        <h:inputHidden id="lat" value="#{mapBean.lat}" />  
        <h:inputHidden id="lng" value="#{mapBean.lng}" />
    </h:form>  
</p:dialog>  

(I didn't change the <script> code in the showcase example, just add it unchanged)

Bean:

@ManagedBean
@ViewScoped
public class MapBean implements Serializable {  

    private MapModel mapModel;  
    private String title;  
    private double lat;  
    private double lng;  
    private String input;

    public MapBean() {  
        mapModel = new DefaultMapModel();  
    }  

    public void addMarker(ActionEvent actionEvent) {  
        mapModel.addOverlay(new Marker(new LatLng(lat, lng), title));  
        addMessage(new FacesMessage(FacesMessage.SEVERITY_INFO, "Marker Added", "Lat:" + lat + ", Lng:" + lng));  
    }  

    public void submit() {
        addMessage(new FacesMessage(FacesMessage.SEVERITY_INFO, "Form submitted", "Amount markers: " + mapModel.getMarkers().size() + ", Input: " + input));
    }

    public void addMessage(FacesMessage message) {  
        FacesContext.getCurrentInstance().addMessage(null, message);  
    }  

    // Getters+setters.
}