OpenLayers示例代码：选择功能
OpenLayers示例代码：选择功能
<!DOCTYPE html>
<html>
<head>
<title>Select Features</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form class="form-inline">
<label>Action type </label>
<select id="type" class="form-control">
<option value="click" selected>Click</option>
<option value="singleclick">Single-click</option>
<option value="pointermove">Hover</option>
<option value="altclick">Alt+Click</option>
<option value="none">None</option>
</select>
<span id="status"> 0 selected features</span>
</form>
<script>
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var vector = new ol.layer.Vector({
source: new ol.source.Vector({
url: 'https://openlayers.org/en/v4.0.1/examples/data/geojson/countries.geojson',
format: new ol.format.GeoJSON()
})
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 2
})
});
var select = null; // ref to currently selected interaction
// select interaction working on "singleclick"
var selectSingleClick = new ol.interaction.Select();
// select interaction working on "click"
var selectClick = new ol.interaction.Select({
condition: ol.events.condition.click
});
// select interaction working on "pointermove"
var selectPointerMove = new ol.interaction.Select({
condition: ol.events.condition.pointerMove
});
var selectAltClick = new ol.interaction.Select({
condition: function(mapBrowserEvent) {
return ol.events.condition.click(mapBrowserEvent) &&
ol.events.condition.altKeyOnly(mapBrowserEvent);
}
});
var selectElement = document.getElementById('type');
var changeInteraction = function() {
if (select !== null) {
map.removeInteraction(select);
}
var value = selectElement.value;
if (value == 'singleclick') {
select = selectSingleClick;
} else if (value == 'click') {
select = selectClick;
} else if (value == 'pointermove') {
select = selectPointerMove;
} else if (value == 'altclick') {
select = selectAltClick;
} else {
select = null;
}
if (select !== null) {
map.addInteraction(select);
select.on('select', function(e) {
document.getElementById('status').innerHTML = ' ' +
e.target.getFeatures().getLength() +
' selected features (last operation selected ' + e.selected.length +
' and deselected ' + e.deselected.length + ' features)';
});
}
};
/**
* onchange callback on the select element.
*/
selectElement.onchange = changeInteraction;
changeInteraction();
</script>
</body>
</html>
说明：
OpenLayers示例代码：选择功能
