如何设置谷歌地图缩放级别以在中心显示所有标记和用户？

Question

我正在创建一个交通应用程序，用户可以在其中单击各种驱动程序进行选择。

我正在从数据库中放置不同的驱动程序：

function multimarker(map) {
    jQuery.ajax({
        url: baseurl + "getdriverlocation.php",

        async: true,
        success: function (data) {
            var myArray = jQuery.parseJSON(data); // instead of JSON.parse(data)

            jQuery(myArray).each(function (index, element) {
                driverlat = element.driver_lat;
                driverlng = element.driver_lng;
                loginid = element.loginid;
                locations.push([driverlat, driverlng, loginid])
            });

            var bounds1 = new google.maps.LatLngBounds();

            for (i = 0; i < locations.length; i++) {

                var latlng1 = new google.maps.LatLng(locations[i][0], locations[i][1]);
                if (google.maps.geometry.spherical.computeDistanceBetween(latlng1, map.getCenter()) < 30000) {
                    drivermarker = new google.maps.Marker({
                        position: latlng1
                    });
                    drivermarker.setMap(map);

                    google.maps.event.addListener(drivermarker, 'click', (function (drivermarker, i) {
                        return function () {
                            driverdetail(locations[i][2]);
                        }
                    })(drivermarker, i));
                    bounds1.extend(latlng1);
                    map.fitBounds(bounds1);
                }
            }
        }
    });
}

并将用户设置为当前位置：

function currentpostionmap() {
    $(document).on("pageshow", "#inside123", function () {
         
        if (navigator.geolocation) {
                    
            function success(pos) {            
                userClat = pos.coords.latitude;
                userClng = pos.coords.longitude;
                var latlng = new google.maps.LatLng(pos.coords.latitude, pos.coords.longitude); 
                var myOptions = {            
                    zoom: 15,
                                center: latlng,
                                mapTypeId: google.maps.MapTypeId.ROADMAP        
                };        
                map = new google.maps.Map(document.getElementById("map"), myOptions);      
                var image123 = 'https:///developers.google.com/maps/documentation/javascript/examples/full/images/beachflag.png';
                marker = new google.maps.Marker({            
                    position: latlng,
                    map: map,
                    icon: image123                
                });
                var infowindow1 = new google.maps.InfoWindow();

                google.maps.event.addListener(marker, 'click', (function (marker, i) {
                    return function () {
                        infowindow1.setContent('YOU');
                        infowindow1.open(map, marker);
                        map.setZoom(20);
                        map.setCenter(marker.getPosition());

                    }
                })(marker));
                multimarker(map);
            }        
            function fail(error) {          
                var latlng = new google.maps.LatLng(18.5204, 73.8567); 
                var myOptions = {            
                    zoom: 10,
                                center: latlng,
                                mapTypeId: google.maps.MapTypeId.ROADMAP        
                };        
                map = new google.maps.Map(document.getElementById("map"), myOptions);             
                marker = new google.maps.Marker({            
                    position: latlng,
                                map: map                   
                });
            }       
            navigator.geolocation.getCurrentPosition(success, fail, {
                maximumAge: 500000,
                enableHighAccuracy: true,
                timeout: 6000
            });    
        }
    });
} 

如何将用户设置为中心并将地图设置为以用户为中心可以查看不同位置的所有标记？

注意：使用当前代码，我面临一个问题，即如果驱动程序远离用户，则只能在中心查看驱动程序。用户必须拖动地图才能看到他们的位置。

Answer 1

你需要做一个多步骤的过程。

1. 将所有标记和“用户”位置添加到google.maps.LatLngBounds 对象
2. 使地图适应该边界。
3. 将地图中心设置为用户的位置。
4. 验证所有标记是否仍在视图中（当前地图边界包含计算的边界），如果不缩小一次。

代码 sn-p：

var geocoder;
var map;
var locations = [
  [-33.890542, 151.274856, 'Bondi Beach'],
  [-33.923036, 151.259052, 'Coogee Beach'],
  [-34.028249, 151.157507, 'Cronulla Beach'],
  [-33.80010128657071, 151.28747820854187, 'Manly Beach'],
  [-33.950198, 151.259302, 'Maroubra Beach']
]

function initialize() {
  var pos = {
    coords: {
      latitude: -33.42502, //-33.8674869,
      longitude: 151.3422193 // 151.2069902
    }
  }
  userClat = pos.coords.latitude;
  userClng = pos.coords.longitude;
  var latlng = new google.maps.LatLng(pos.coords.latitude, pos.coords.longitude);
  var myOptions = {
    zoom: 15,
    center: latlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };
  map = new google.maps.Map(document.getElementById("map"), myOptions);
  var image123 = 'https:///developers.google.com/maps/documentation/javascript/examples/full/images/beachflag.png';
  //                var bounds = new google.maps.LatLngBounds();        
  marker = new google.maps.Marker({
    position: latlng,
    map: map,
    icon: image123
  });
  var infowindow1 = new google.maps.InfoWindow();

  google.maps.event.addListener(marker, 'click', (function(marker, i) {
    return function() {
      infowindow1.setContent('YOU');
      infowindow1.open(map, marker);
      map.setZoom(20);
      map.setCenter(marker.getPosition());

    }
  })(marker));

  multimarker(map, latlng, infowindow1);

}

function multimarker(map, userloc, infowindow) {
  var bounds1 = new google.maps.LatLngBounds();

  for (i = 0; i < locations.length; i++) {

    var latlng1 = new google.maps.LatLng(locations[i][0], locations[i][1]);
    // if (google.maps.geometry.spherical.computeDistanceBetween(latlng1, map.getCenter()) < 30000) {
    drivermarker = new google.maps.Marker({
      position: latlng1,
      icon: "http://maps.google.com/mapfiles/ms/micons/blue.png",
      map: map
    });
    drivermarker.setMap(map);

    google.maps.event.addListener(drivermarker, 'click', (function(marker, i) {
      return function(evt) {
        infowindow.setContent(locations[i][2]);
        infowindow.open(map, marker);
      }
    })(drivermarker, i));
    bounds1.extend(latlng1);
    map.fitBounds(bounds1);
    // }
  }
  bounds1.extend(userloc);
  map.fitBounds(bounds1);
  // wait for the bounds change to happen
  google.maps.event.addListenerOnce(map, 'bounds_changed', function() {
    // set the center on the user
    map.setCenter(userloc);
    // wait for the center to change
    google.maps.event.addListenerOnce(map, 'bounds_changed', function() {
      // check to see if all the markers are still in bounds
      if ((!map.getBounds().contains(bounds1.getNorthEast())) ||
        (!map.getBounds().contains(bounds1.getSouthWest()))) {
        // if not zoom out one level
        console.log(map.getZoom() + " zoom-1 will be " + (map.getZoom() - 1));
        map.setZoom(map.getZoom() - 1);
      }
    });
  });
}
google.maps.event.addDomListener(window, "load", initialize);

html,
body,
#map {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="map"></div>