使用 JSON 的 Google 地图标记。地图上仅显示循环中的最后一个标记

我正在使用 JSON（本地文件）加载一些标记信息，但由于某种原因，只有循环中的最后一个标记显示在地图上。

我可以看到在控制台中正确打印了所有坐标，所以我很确定循环很好，而且大部分代码都很好。

<script>
  function myMap() {

        var mapCanvas = document.getElementById("content_map" );
        var mapOptions = {
            center: new google.maps.LatLng(55.812757, -4.195363),
            zoom: 5,
            disableDefaultUI: true,
            styles: [
                  {
                    "elementType": "geometry",

                    "stylers": [
                      {
                        "color": "#f5f5f5"
                      }
                    ]
                  },
                  {
                    "elementType": "labels.icon",
                    "stylers": [
                                  {
                                    "visibility": "off"
                                  }
                                ]
                              },
                              {
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#616161"
                                  }
                                ]
                              },
                              {
                                "elementType": "labels.text.stroke",
                                "stylers": [
                                  {
                                    "color": "#f5f5f5"
                                  }
                                ]
                              },
                              {
                                "featureType": "administrative.land_parcel",
                                "elementType": "labels",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "administrative.land_parcel",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#bdbdbd"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#eeeeee"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi",
                                "elementType": "labels.text",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#757575"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi.business",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi.park",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#e5e5e5"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi.park",
                                "elementType": "labels.text",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "poi.park",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#0d99ba"
                                  }
                                ]
                              },
                              {
                                "featureType": "road",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#ffffff"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.arterial",
                                "elementType": "labels",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.arterial",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#757575"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.highway",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#9e9e9e"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.highway",
                                "elementType": "labels",
                                "stylers": [
                                  {
                                    "visibility": "on"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.highway",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#616161"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.local",
                                "stylers": [
                                  {
                                    "visibility": "off"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.local",
                                "elementType": "labels",
                                "stylers": [
                                  {
                                    "visibility": "off"
                                  }
                                ]
                              },
                              {
                                "featureType": "road.local",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#9e9e9e"
                                  }
                                ]
                              },
                              {
                                "featureType": "transit.line",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#e5e5e5"
                                  }
                                ]
                              },
                              {
                                "featureType": "transit.station",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#eeeeee"
                                  }
                                ]
                              },
                              {
                                "featureType": "water",
                                "elementType": "geometry",
                                "stylers": [
                                  {
                                    "color": "#0d99ba"
                                  }
                                ]
                              },
                              {
                                "featureType": "water",
                                "elementType": "labels.text.fill",
                                "stylers": [
                                  {
                                    "color": "#9e9e9e"
                                  }
                                ]
                              }
                            ]
        };
        var contentString = '<div id="content">'+

        '<img src="./img/logo_img_map.png" alt="">'+
        '</div>';

        var infowindow = new google.maps.InfoWindow({
          content: contentString
        });


        $.getJSON('data.json', function(json) {



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

                addMarker(json.ChargeDevice[i].ChargeDeviceLocation.Latitude,json.ChargeDevice[i].ChargeDeviceLocation.Longitude);
                console.log(json.ChargeDevice[i].ChargeDeviceLocation.Latitude, json.ChargeDevice[i].ChargeDeviceLocation.Longitude);
            };


            function addMarker(lat,lng) {

                    var image = './img/logo_img_map.png';
                    var map = new google.maps.Map(mapCanvas, mapOptions);
                    var marker = new google.maps.Marker({
                        position: new google.maps.LatLng(lat,lng),
                        map: map,
                        icon: image
                    });

            };




      });

    };

  </script>
  <script src="https://maps.googleapis.com/maps/api/js?key=MYKEY"></script>

我现在已经查看了大量线程，但我无法弄清楚为什么它在这种情况下不起作用。我正在运行我的函数，因为它发生在循环中......所以标记真的不应该保留吗？

注意：我的 API 密钥已被删除，因此它不会在线显示，但它可以在我的网络服务器上运行并且地图加载正常。实际上只有一个标记显示，而我的 JSON 文件中有 2 个数据集。

我还没有完成点击环境，但我认为现在这不重要，是吗？

任何帮助，将不胜感激！