Add SelectEvent to Select interaction

Fixes

examples/select-features.html

@@ -35,6 +35,7 @@
           <h4 id="title">Select features example</h4>
           <p id="shortdesc">Example of using the Select interaction. Choose between <code>Single-click</code>, <code>Click</code> and <code>Hover</code> as the event type for selection in the combobox below. When using <code>Single-click</code> or <code>Click</code> you can hold do <code>Shift</code> key to toggle the feature in the selection.</p>
           <p>Note: when <code>Single-click</code> is used double-clicks won't select features. This in contrast to <code>Click</code>, where a double-click will both select the feature and zoom the map (because of the <code>DoubleClickZoom</code> interaction). Note that <code>Single-click</code> is less responsive than <code>Click</code> because of the delay it uses to detect double-clicks.</p>
+          <p>In this example, a listener is registered for the Select interaction's <code>select</code> event in order to update the selection status below.
           <form class="form-inline">
             <label>Action type &nbsp;</label>
               <select id="type">
@@ -43,6 +44,7 @@
                 <option value="click">Click</option>
                 <option value="pointermove">Hover</option>
               </select>
+              <span id="status">&nbsp;0 selected features</span>
           </form>
           <div id="docs">
             <p>See the <a href="select-features.js" target="_blank">select-features.js source</a> to see how this is done.</p>

examples/select-features.js

@@ -61,6 +61,11 @@ var changeInteraction = function() {
   }
   if (select !== null) {
     map.addInteraction(select);
+    select.on('select', function(e) {
+      $('#status').html(' ' + e.target.getFeatures().getLength() +
+          ' selected features (last operation selected ' + e.selected.length +
+          ' and deselected ' + e.deselected.length + ' features)');
+    });
   }
 };
 

src/ol/interaction/selectinteraction.js

@@ -3,6 +3,7 @@ goog.provide('ol.interaction.Select');
 goog.require('goog.array');
 goog.require('goog.asserts');
 goog.require('goog.events');
+goog.require('goog.events.Event');
 goog.require('goog.functions');
 goog.require('ol.CollectionEventType');
 goog.require('ol.Feature');
@@ -13,6 +14,51 @@ goog.require('ol.interaction.Interaction');
 goog.require('ol.style.Style');
 
 
+/**
+ * @enum {string}
+ */
+ol.SelectEventType = {
+  /**
+   * Triggered when feature(s) has been (de)selected.
+   * @event ol.SelectEvent#select
+   * @api
+   */
+  SELECT: 'select'
+};
+
+
+
+/**
+ * @classdesc
+ * Events emitted by {@link ol.interaction.Select} instances are instances of
+ * this type.
+ *
+ * @param {string} type The event type.
+ * @param {Array.<ol.Feature>} selected Selected features.
+ * @param {Array.<ol.Feature>} deselected Deselected features.
+ * @extends {goog.events.Event}
+ * @constructor
+ */
+ol.SelectEvent = function(type, selected, deselected) {
+  goog.base(this, type);
+
+  /**
+   * Selected features array.
+   * @type {Array.<ol.Feature>}
+   * @api
+   */
+  this.selected = selected;
+
+  /**
+   * Deselected features array.
+   * @type {Array.<ol.Feature>}
+   * @api
+   */
+  this.deselected = deselected;
+};
+goog.inherits(ol.SelectEvent, goog.events.Event);
+
+
 
 /**
  * @classdesc
@@ -140,6 +186,7 @@ ol.interaction.Select.handleEvent = function(mapBrowserEvent) {
   var features = this.featureOverlay_.getFeatures();
   var /** @type {Array.<ol.Feature>} */ deselected = [];
   var /** @type {Array.<ol.Feature>} */ selected = [];
+  var change = false;
   if (set) {
     // Replace the currently selected feature(s) with the feature(s) at the
     // pixel, or clear the selected feature(s) if there is no feature at
@@ -156,7 +203,9 @@ ol.interaction.Select.handleEvent = function(mapBrowserEvent) {
         features.item(0) == selected[0]) {
       // No change
     } else {
+      change = true;
       if (features.getLength() !== 0) {
+        deselected = Array.prototype.concat(features.getArray());
         features.clear();
       }
       if (this.multi_) {
@@ -189,6 +238,13 @@ ol.interaction.Select.handleEvent = function(mapBrowserEvent) {
       features.remove(deselected[i]);
     }
     features.extend(selected);
+    if (selected.length > 0 || deselected.length > 0) {
+      change = true;
+    }
+  }
+  if (change) {
+    this.dispatchEvent(
+        new ol.SelectEvent(ol.SelectEventType.SELECT, selected, deselected));
   }
   return ol.events.condition.pointerMove(mapBrowserEvent);
 };