Show markers on google maps dynamically -Rails 3.2

Question

i have a working code that shows multiple markers on google map using geocoder such as @nearbys = Place.near("#{params[:address]}", 5,:order => "distance",:units => :km) @nearbys.first(5) and i display the markers using the below code

function initialize() {
    var map;
    var bounds = new google.maps.LatLngBounds();
    var mapOptions = {
        mapTypeId: 'roadmap'
    };

    // Display a map on the page
    map = new google.maps.Map(document.getElementById("map-canvas-guest"), mapOptions);
    map.setTilt(45);

    // adding Multiple Markers from ruby object
    var markers = [
        ['<%= @nearbys[0].title %>', '<%= @nearbys[0].latitude %>','<%= @nearbys[0].longitude %>'],
        ['<%= @nearbys[1].title %>', '<%= @nearbys[1].latitude %>','<%= @nearbys[1].longitude %>'],
        ['<%= @nearbys[2].title %>', '<%= @nearbys[2].latitude %>','<%= @nearbys[2].longitude %>'],
        ['<%= @nearbys[3].title %>', '<%= @nearbys[3].latitude %>','<%= @nearbys[3].longitude %>']
        ,
        ['<%= @nearbys[4].title %>', '<%= @nearbys[4].latitude %>','<%= @nearbys[4].longitude %>']
      ];

    // adding Info Window Content 
    var infoWindowContent = [
        ['<div class="info_content" >' +
        '<h3><%= @nearbys[0].title %></h3>' +'</br>'+
        '<p><%= @nearbys[0].about %></p>' +       
         '</div>'],
        ['<div class="info_content">' +
        '<h3><%= @nearbys[1].title %></h3>' +
        '<p><%= @nearbys[1].about %></p>' +
        '</div>'],
                ['<div class="info_content">' +
        '<h3><%= @nearbys[2].title %></h3>' +'</br>'+
        '<p><%= @nearbys[2].about %></p>' +
        '</div>'],
                ['<div class="info_content">' +
        '<h3><%= @nearbys[3].title %></h3>' +'</br>'+
        '<p><%= @nearbys[2].about %>/p>' +
        '</div>'],
                ['<div class="info_content">' +
        '<h3><%= @nearbys[4].title %></h3>' +'</br>'+
        '<p><%= @nearbys[4].about %></p>' +
        '</div>']
    ];

    // Display multiple markers on a map
    var infoWindow = new google.maps.InfoWindow(), marker, i;

    // Loop through our array of markers & place each one on the map  
    for( i = 0; i < markers.length; i++ ) {
        var position = new google.maps.LatLng(markers[i][1], markers[i][2]);
        bounds.extend(position);
        marker = new google.maps.Marker({
            position: position,
            map: map,
            title: markers[i][0]
        });

        // Allow each marker to have an info window    
        google.maps.event.addListener(marker, 'click', (function(marker, i) {
            return function() {
                infoWindow.setContent(infoWindowContent[i][0]);
                infoWindow.open(map, marker);


            }
        })(marker, i));

        // Automatically center the map fitting all markers on the screen
        map.fitBounds(bounds);

    }

    // Override our map zoom level once our fitBounds function runs (Make sure it only runs once)
    var boundsListener = google.maps.event.addListener((map), 'bounds_changed', function(event) {
        this.setZoom(14);
        google.maps.event.removeListener(boundsListener);
    });

}//initialize ends

BUT the problem is:-what if @nearbys has less than 5 count,then this code fails.SO i have been trying to make it dynamic using jquery arrays but its not working because i think my code is missing something to work it dynamically. it should be something like this..

var array=<%= @nearbys%>;
var markers=[];
var infowindows=[];
array.each(function(index){
markers.push('<%= @nearbys[0].title %>', '<%= @nearbys[0].latitude %>','<%= @nearbys[0].longitude %>');
infowindows.push('<div class="info_content" >'+'<h3><%= @nearbys[0].title %></h3>' +'</br>'+
        '<p><%= @nearbys[0].about %></p>'+'</div>');

})

..SO how i can achieve this........to make this dynamic so that above working code doesnt breaks with the newly added code.

Answer 1

Hello Friends by doing with Google Maps With Rails i have searched the information from google maps site and Gmaps4rails i have done Multiple Markers and Info-window her is the code

My Controller

    @users = User.all
    @hash = Gmaps4rails.build_markers(@users) do |user, marker|
      marker.lat user.latitude
      marker.lng user.longitude
      marker.infowindow user.title` 
    end

In My View

window.onload = function () {
    var markers = <%=raw @hash.to_json %>;
    var mapOptions = {
        center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
        zoom: 15,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    var infoWindow = new google.maps.InfoWindow();
    var map = new google.maps.Map(document.getElementById("map"), mapOptions);
    for (i = 0; i < markers.length; i++) {
        var data = markers[i]
        var myLatlng = new google.maps.LatLng(data.lat, data.lng);
        marker = new google.maps.Marker({
            position: myLatlng,
            map: map,
            title: data.title
        });
        (function (marker, data) {
            google.maps.event.addListener(marker, "click", function (e) {
                infoWindow.setContent(data.description);
                infoWindow.open(map, marker);
            });
        })(marker, data);
    }
}

Answer 2

well after struggling with jquery arrays and json ,i was able to find this best solution...this is working in all scenarios and all i need is to handle empty and null conditions,which i already did and its working the way i needed.HOPE THIS HELPS SOMEONE

my controller

def show_nearby_locations

  @nearbys = Place.near("#{params[:address]}", 5,:order => "distance",:units => :km)
  @nearbys.first(10)

end

in my view file

<%= javascript_tag do%>
 window.nearbys= <%=raw @nearbys.to_json %>;

<%end%>

this is my script inside view

function initialize() {
    var map;
    var bounds = new google.maps.LatLngBounds();
    var mapOptions = {
        mapTypeId: 'roadmap'
    };

    // Display a map on the page
    map = new google.maps.Map(document.getElementById("map-canvas-guest"), mapOptions);
    map.setTilt(45);            

    var markers=[];
    var infoWindowContent=[];
    $.each(nearbys, function(index) { 

        console.log( data[0][index].latitude,data[0][index].longitude );
        markers.push([nearbys[index]['title'], nearbys[index]['latitude'],nearbys[index]['longitude']]);
        infoWindowContent.push(['<div class="info_content" >' +
        '<h3 style="color: rgb(<%= rand(0..200)%>,<%= rand(0..200)%> ,<%= rand(0..200)%>);">'+nearbys[index]['title']+'</h3>' +'</br>'+
        '<p>'+nearbys[index]['about']+'</p>' +       
         '</div>']);

        });   

       // Display multiple markers on a map
       var infoWindow = new google.maps.InfoWindow(), marker, i;        
      // Loop through our array of markers & place each one on the map  
      for( i = 0; i < markers.length; i++ ) {
          var position = new google.maps.LatLng(markers[i][1], markers[i][2]);
          bounds.extend(position);
          marker = new google.maps.Marker({
            position: position,
            map: map,
            title: markers[i][0]
        });

        // Allow each marker to have an info window    
        google.maps.event.addListener(marker, 'click', (function(marker, i) {
            return function() {
                infoWindow.setContent(infoWindowContent[i][0]);
                infoWindow.open(map, marker);


            }
        })(marker, i));

        // Automatically center the map fitting all markers on the screen
        map.fitBounds(bounds);

    }

    // Override our map zoom level once our fitBounds function runs (Make sure it only runs once)
    var boundsListener = google.maps.event.addListener((map), 'bounds_changed', function(event) {
        this.setZoom(14);
        google.maps.event.removeListener(boundsListener);
    });

}//initialize ends