The last requirement we need to implement, states that the application must change the colors of the polygons as the user clicks on the year buttons of the navigation bar. As before, we will achieve this through the year:change custom event we'll add to the map that will be triggered by the navigation buttons, and handled by the shapes.
Microsoft.Maps.Events.addHandler(this._map, 'year:change', function(e) {
self._changeYear(e.currentYear);
});The preceding lines, which we add to the _bind method of the Shape class, bind the year:change event to the _changeYear function. Note that this function expects that the eventArgs object passed should contain information about the year selected in the form of its index in the YEARS array. It's time to write the handler as follows:
_changeYear: function(currentYear) {
this._updateParty(currentYear);
this._shape.setOptions({
strokeColor: this._getColor({stroke: true}),
fillColor: this._getColor()
});
}This method...