scope of markers variable for google maps (gmaps4rails gem)

问题

I'm trying to understand javascript, and the way variables are passed around, but I'm not doing too well. I'm trying to refresh a google map's markers with ajax, but nothing is happening.

I submit a form, which sends some variables to the controller. Some stuff is processed, and it responds with .js to...

find.js.erb

$('#collapseTwo ul').html("<%= j render partial: 'events/sidebar', collection: @events %>");

alert(<%= raw @hash.to_json %>);

clearMarkers();


markers = handler.addMarkers(<%= raw @hash.to_json %>, {
  draggable: false
});

The render fires fine, so everything is working there, but I can't seem to get a hold of the markers to refresh the map. That alert shows [object Object], so that's likely correct, but no action on the markers.

I made some modifications to marker.coffee in the form of

clear: ->
  @getServiceObject().setMap(null)

show: ->
  @getServiceObject().setVisible(true)

hide: ->
  @getServiceObject().setVisible(false)

so that clearMarkers(); works. It's in another file, where I'm storing some other actions

events.js.coffee

jQuery ->
  ...
  ...

@clearMarkers = ->
  for marker in Gmaps.store.markers
    marker.clear()
  Gmaps.store.markers = []

So... I call the map initially in with...

jQuery ->
  handler = Gmaps.build 'Google'
  handler.buildMap { 
    provider: { 
      minZoom: 3
    }, internal: {id: 'map'} }, ->

      markers = handler.addMarkers( $('#map').data('events'), 
        draggable: false
        flat: false
      )

      #moves map to marker clicked + open infowindow
      $(document).on 'click', '#sideBar li', ->
        markers[$(this).data('marker')].panTo()
        markers[$(this).data('marker')].click()

That function on the bottom there... the only way I had access to the markers array was because it was inside the handler.buildMap function. So, should the markers variable be global? How else can I act on them?

Also, the handler variable... that's it seems to me like that should be available everywhere. I tried manually putting the @hash into .addMarkers(), but the handler didn't build the markers.

回答1:

You need a store accessible globally.

I suggest the following:

Gmaps.store = {}
jQuery ->
  Gmaps.store.handler = Gmaps.build 'Google'
  Gmaps.store.handler.buildMap...
    Gmaps.store.markers = Gmaps.store.handler.addMarkers(...)

You can access the variables within your js.erb as well.

来源：https://stackoverflow.com/questions/19737094/scope-of-markers-variable-for-google-maps-gmaps4rails-gem