javascript - can't remove google map markers

Question

I'm having some trouble with google map markers. I have an array that contains 7 locations. When the page loads, a "for" loop runs through the array and places the first four locations as markers on the map. What I then want to happen is to be able to click the "Remove and add markers" button, which would run a function (called addMarker2) to remove the original 4 location markers and add the last 3 location markers to the map.

I've tested the function to only add the last 3 markers, and it works fine. But when I add the code to remove the first 4 markers before adding the last 3 markers, it doesn't work anymore. I've been searching all over for an answer, and almost everything I've found seems to indicate that I'm doing it correctly, although clearly I'm not.

var mapCanvas = document.getElementById('map-canvas');
var mapOptions = {
  center: new google.maps.LatLng(40, -95),
  zoom: 4,
  mapTypeId: google.maps.MapTypeId.ROADMAP
}

// create the map
var map = new google.maps.Map(mapCanvas, mapOptions);

// array of locations
var pins = [
         ['Cleveland',41.499321,-81.694359],
         ['Florence',34.195435,-79.762566],
         ['Knoxville',35.960638,-83.920739],
         ['Memphis',35.149532,-90.048981],
         ['Nashville',36.162664,-86.781602],
         ['Phoenix',33.448376,-112.074036],
         ['Toronto',43.653225,-79.383186]
    ];


// Loop through the array of locations & place each one on the map  
for( i = 0; i < 4; i++ ) {
    var position = new google.maps.LatLng(pins[i][1], pins[i][2]);
    var marker = new google.maps.Marker({
        position: position,
        map: map,
        icon: 'http://i.imgur.com/FPiUErC.png',
        title: pins[i]['0']
    });
} // end of the for loop


function addmarker2() {
    // remove the first four markers
    for( i = 0; i < 4; i++ ) {
       pins[i].setMap(null); 
    }

    // add the last three markers
    for( i = 4; i < 7; i++ ) {
        var myPosition = new google.maps.LatLng(pins[i][1], pins[i][2]);
        var marker = new google.maps.Marker({
            position: myPosition,
            map: map,
            icon: 'http://i.imgur.com/FPiUErC.png',
            title: pins[i][0]
        });
    } // end of for loop
} // end of addmarker2 function


$("#mysubmit").click(addmarker2);

Something has to be incorrect with the way I am using setMap(null). I have a jsfiddle of the code. It won't work at first, but if you comment out the "for" loop that is attempting to remove the first 4 markers, then it will successfully add the last 3. I just need it to do both.

Answer 1

In case anyone else is having the same problem and finds this question, as ray stated, I needed to create an array to push the markers into and then apply the setMap(null) to the markers array, as opposed to applying it to the original array (pins[]) that contained my location info.

var mapCanvas = document.getElementById('map-canvas');
var mapOptions = {
  center: new google.maps.LatLng(40, -95),
  zoom: 4,
  mapTypeId: google.maps.MapTypeId.ROADMAP
}

// create the map
var map = new google.maps.Map(mapCanvas, mapOptions);

// array of locations
var pins = [
         ['Cleveland',41.499321,-81.694359],
         ['Florence',34.195435,-79.762566],
         ['Knoxville',35.960638,-83.920739],
         ['Memphis',35.149532,-90.048981],
         ['Nashville',36.162664,-86.781602],
         ['Phoenix',33.448376,-112.074036],
         ['Toronto',43.653225,-79.383186]
    ];

// this array will hold the markers
var markers = [];

// Loop through the array of locations & place each one on the map  
for( i = 0; i < 4; i++ ) {
    var position = new google.maps.LatLng(pins[i][1], pins[i][2]);
    var marker = new google.maps.Marker({
        position: position,
        map: map,
        icon: 'http://i.imgur.com/FPiUErC.png',
        title: pins[i]['0']
    });
    //each marker is added to the markers array
    markers.push(marker);
} // end of the for loop


function addmarker2() {
    // remove the first four markers
    for( i = 0; i < 4; i++ ) {
       // the loop removes the first four results from the markers array
       markers[i].setMap(null); 
    }

    // add the last three markers
    for( i = 4; i < 7; i++ ) {
        var myPosition = new google.maps.LatLng(pins[i][1], pins[i][2]);
        var marker = new google.maps.Marker({
            position: myPosition,
            map: map,
            icon: 'http://i.imgur.com/FPiUErC.png',
            title: pins[i][0]
        });
    } // end of for loop
} // end of addmarker2 function


$("#mysubmit").click(addmarker2);

Answer 2

I've already live debugging by typing on developer console, and i've found a way to remove all markers. (which saved using array.push() method)

Here is the code -- just call neutralize() :

function neutralize() {
    for (var i = 0; i < markers.length; i++) {
        try{
            markers[i].f.setMap(null);
         }
        catch{
            markers[i].setMap(null);
         }    
    }

    markers = [];
}