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javascriptapigoogle-maps-api-3geolocation

Creating a button that shows my current location using geolocation


I want to create a button which shows my current location using geolocation. Here is my code which I took from the developers page.

<!DOCTYPE html>
<html>
  <head>
    <title>Geolocation</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      html, body, #map-canvas {
        height: 100%;
        margin: 0px;
        padding: 0px
      }

    </style>
    <script src="https://maps.googleapis.com/maps/api/js?v=3.exp&signed_in=true"></script>

    <script>
// Note: This example requires that you consent to location sharing when
// prompted by your browser. If you see a blank space instead of the map, this
// is probably because you have denied permission for location sharing.

var map;

function initialize() {
  var mapOptions = {
    zoom: 16
  };
  map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);

  // Try HTML5 geolocation
  if(navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(position) {
      var pos = new google.maps.LatLng(position.coords.latitude,
                                       position.coords.longitude);

      var infowindow = new google.maps.InfoWindow({
        map: map,
        position: pos,
        content: 'Location found using HTML5.'
      });

      map.setCenter(pos);
    }, function() {
      handleNoGeolocation(true);
    });
  } else {
    // Browser doesn't support Geolocation
    handleNoGeolocation(false);
  }

  var centerControlDiv = document.createElement('div');
  var centerControl = new CenterControl(centerControlDiv, map, chicago);

  centerControlDiv.index = 1;
  map.controls[google.maps.ControlPosition.BOTTOM_LEFT].push(centerControlDiv);

}

function handleNoGeolocation(errorFlag) {
  if (errorFlag) {
    var content = 'Error: The Geolocation service failed.';
  } else {
    var content = 'Error: Your browser doesn\'t support geolocation.';
  }

  var options = {
    map: map,
    position: new google.maps.LatLng(60, 105),
    content: content
  };

  var infowindow = new google.maps.InfoWindow(options);
  map.setCenter(options.position);


}






google.maps.event.addDomListener(window, 'load', initialize);




    </script>
  </head>
  <body>
    <div id="map-canvas"></div>



  </body>
</html>

I found a post here on these forums saying to use this code:

var myloc = new google.maps.Marker({
    clickable: false,
    icon: new google.maps.MarkerImage('//maps.gstatic.com/mapfiles/mobile/mobileimgs2.png',
                                                    new google.maps.Size(22,22),
                                                    new google.maps.Point(0,18),
                                                    new google.maps.Point(11,11)),
    shadow: null,
    zIndex: 999,
    map: // your google.maps.Map object
});

if (navigator.geolocation) navigator.geolocation.getCurrentPosition(function(pos) {
    var me = new google.maps.LatLng(pos.coords.latitude, pos.coords.longitude);
    myloc.setPosition(me);
}, function(error) {
    // ...
});

But it doesn't seem to work for me. I don't know why. Can anyone try to explain me and tell me where to put the code for get it work?

I would rather use a "custom control" to show my current position, if someone can help me make one like that, this way I can put it wherever I want to.


Solution

  • Here is a simple example on how to create a custom control and bind a click event listener to it to geolocate the user.

    var map;
    
    function initialize() {
    
        var mapOptions = {
            center: new google.maps.LatLng(10, 10),
            zoom: 5
        };
    
        map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
    
        // Create the DIV to hold the control and call the constructor passing in this DIV
        var geolocationDiv = document.createElement('div');
        var geolocationControl = new GeolocationControl(geolocationDiv, map);
    
        map.controls[google.maps.ControlPosition.TOP_CENTER].push(geolocationDiv);
    }
    
    function GeolocationControl(controlDiv, map) {
    
        // Set CSS for the control button
        var controlUI = document.createElement('div');
        controlUI.style.backgroundColor = '#444';
        controlUI.style.borderStyle = 'solid';
        controlUI.style.borderWidth = '1px';
        controlUI.style.borderColor = 'white';
        controlUI.style.height = '28px';
        controlUI.style.marginTop = '5px';
        controlUI.style.cursor = 'pointer';
        controlUI.style.textAlign = 'center';
        controlUI.title = 'Click to center map on your location';
        controlDiv.appendChild(controlUI);
    
        // Set CSS for the control text
        var controlText = document.createElement('div');
        controlText.style.fontFamily = 'Arial,sans-serif';
        controlText.style.fontSize = '10px';
        controlText.style.color = 'white';
        controlText.style.paddingLeft = '10px';
        controlText.style.paddingRight = '10px';
        controlText.style.marginTop = '8px';
        controlText.innerHTML = 'Center map on your location';
        controlUI.appendChild(controlText);
    
        // Setup the click event listeners to geolocate user
        google.maps.event.addDomListener(controlUI, 'click', geolocate);
    }
    
    function geolocate() {
    
        if (navigator.geolocation) {
    
            navigator.geolocation.getCurrentPosition(function (position) {
    
                var pos = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
    
                // Create a marker and center map on user location
                marker = new google.maps.Marker({
                    position: pos,
                    draggable: true,
                    animation: google.maps.Animation.DROP,
                    map: map
                });
    
                map.setCenter(pos);
            });
        }
    }
    
    initialize();
    

    JSFiddle demo