Ok, thanks. Now the unregistering works and the function that gets called when the event was triggered only runs once. But another problem appeared.
The layer that contains the features I want to select is shown or hidden depending on the resolution. For this reason I need to query the WFS-Server if the searched feature is not in the current bounds or the layer is not shown at all because of the resolution of the map. By doing this I can get the bounds of the searched feature, zoom to it and then wait for the layer that contains features of this featuretype to load. When it has finished loading I can select the feature.
So, what´s the problem now? If the feature is already in the layer so that no extra WFS-query has to be performed selecting it works flawlessly. I can click out of this feature and it get´s unselected etc.
On the other hand, when an extra-WFS-request has to be performed the feature also gets selected and the map zooms to it. BUT: It leads to a very strange behavior:
1. when clicking outside the feature it doesn´t get unselected. It only get´s unselected when clicking on another feature
2. some features that I select after this immediately get unselected again after they´ve got marked as selected and the map zoomed to them
This behaviour persists so I guess something got corrupted in the script. It also is existent when I´m only zooming to the queried feature (without selecting it).
If needed I can give you the URL to the application via private mail but I can´t make it public.
Here´s the code segment with comments:
function zoomToTrigger(evt){
aufrufCounter ++; //just for debugging
document.getElementById('selectStatus').innerHTML+="zoomTrigger ausgeführt;<br>";
// unregister the loadend event
wfsLiegenschaften.events.unregister('loadend',wfsLiegenschaften,zoomToTrigger);
//
zoomToLiegenschaft(globalID);
};
/* Given an id this method first calls the searchFeature-method to find out if this feature
is already loaded into the layer. This is necessary because the layer is only visible in an
given resolution-interval. If that´s not the case (false returned) it calls the getFeatureBounds-method
which performs a wfs-filter-request, calculates the bounds for the feature, zooms to this extend and waits
for the layer to load and after that event was triggerd calls the zoomToTrigger-method which
unregister the loadend-event and recursively calls the zoomToLiegenschaft-method */
function zoomToLiegenschaft(id){
// remembers the id that was searched for in a global attribute
globalID = id;
searchResult = searchFeature(wfsLiegenschaften,id);
if(searchResult==false){
getFeatureBounds('jos:Liegenschaften','FlaechenID',id);
}
};
/* finds out if a feature with the given id exists in the layer. If it´s the case
this feature gets selected (selecting it automatically zooms to it´s bounds) and true is
returned. If the feature is not available "false" is returned. */
function searchFeature(layer,id){
for(var feat in layer.features){
if(layer.features[feat].attributes.FlaechenID == id){
selectControl.unselectAll();
selectControl.select(layer.features[feat]);
return true;
}
}
return false;
};
function getFeatureBounds(layer,filterAttribute,filterValue){
var params = new Array();
// Schreiben der gesuchten ID in globale Variable, damit sie für andere Methoden zur Verfügung steht
temp_filterValue = filterValue;
temp_layer = layer;
params[0] = "typename="+layer;
params[1] = "FILTER=<Filter>";
params[1] += "<PropertyIsEqualTo>";
params[1] += "<PropertyName>" + filterAttribute + "</PropertyName>";
params[1] += "<Literal>" + filterValue + "</Literal>";
params[1] += "</PropertyIsEqualTo>";
params[1] += "</Filter>";
try{
OpenLayers.loadURL('//GEOSERVER-Location//',('?srs=EPSG:31468&SERVICE=WFS&VERSION=1.0.0&REQUEST=GetFeature&'+params[0]+'&'+params[1]),readGML,readGML,loadFailure);
}
catch(err){
showError("@loadGML: Fehler beim Laden der GML (" + err.message + ")");
}
}
function loadFailure(response){
showError("Fehler beim Laden der GML (" + err.message +")");
}
function readGML(response){
// Parse the GML
gml = new OpenLayers.Format.GML();
featureList = gml.read(response.responseText);
// Get the Bounds for the received features
featureBoundsList = new Array();
for(var features in featureList){
featureBoundsList[features] = featureList[features].geometry.getBounds();
}
// calculate the Bounds for the feature/features
totalBounds = 0;
for(var bounds in featureBoundsList){
if(totalBounds == 0){totalBounds = featureBoundsList[bounds];}
else{totalBounds.extend(featureBoundsList[bounds]);}
}
// zoom to the calculated bounds
map.zoomToExtent(totalBounds);
// register when the layer that contains the features finished loading and call the zoomToTrigger-method
wfsLiegenschaften.events.register('loadend',wfsLiegenschaften,zoomToTrigger);
}
Eric Lemoine-2-2 wrote:
On Thu, Oct 29, 2009 at 3:17 PM, Max Stephan <x.zam@gmx.net> wrote:
>
> Hi Eric,
>
> thanks for your help but I don't get the idea what your code is doing. Could
> you explain it?
it was just to show you that unregister works as expected.
> Furthermore what is the unregister function in general
> exactly doing. Am I right in thinking it stops the previous defined
> registering of an event or is it doing something else?
it unregisters an event listener, it doesn't stop the event from being
triggered.
--
Eric Lemoine
Camptocamp France SAS
Savoie Technolac, BP 352
73377 Le Bourget du Lac, Cedex
Tel : 00 33 4 79 44 44 96
Mail : eric.lemoine@camptocamp.com
http://www.camptocamp.com_______________________________________________
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