如何每5秒更新一次传单标记 [英] How to update leaflet markers for every 5 seconds

问题描述

我正在制作传单地图和标记.

I am working on a Leaflet map and markers.

我正在从JSON获取标记latlng并正确显示它.

I am getting markers latlng from JSON and showing it correctly.

getLatLng()

function getLatLng() {
  var details = '/equipment/api/getLatLong';
  $.ajax({
    url: details,
    method: 'get'
  }).done(function(response) {

    $('.subSection').html('').append('<section><button type="button" onclick="hideEquipmentDetails()"><i class="fa fa-times"></i></button></section>');
    var equipmentDetails = response.data.filters;
    console.log(equipmentDetails)
    $.each(equipmentDetails, function(i, value) {
      L.marker([value.latitude, value.longitude]).addTo(map).bindPopup('<b><span> Name:</span>' + value.name + '</b>');
    })
  });
}

setInterval(function() {
  getLatLng();
}, 5000)

我每5秒钟刷新一次方法.

I am refreshing the method for every 5 seconds.

所以我需要在更新的latlng中显示标记，并且应该隐藏旧标记.

So I need to show the markers in updated latlng and old markers should be hidden.

setInterval(function() {
  //L.marker.setOpacity(0);
  //L.markerClusterGroup()
  //markers.clearLayers();
  //map.removeLayer(L.marker);
  //markers.removeLayer()
  //L.marker().removeTo(map);
  getLatLng();
}, 5000)

我尝试了所有方法来实现这一目标，但我做不到.

I tried every options to achieve this but I couldn't.

还有其他方法吗?

否则，我应该再定义一个数组来存储初始latlng值，然后每次检查latlng是否被更改(在这种情况下，我只能正确替换已更新的latlng标记吗?不需要每次都替换所有标记吗? )

Otherwise should I define one more array to store the initial latlng values then to check each time whether latlng is changed or not (in this scenario I can replace only updated latlng markers right?No need to replace all markers every time right?)

推荐答案

您无需在每次更新时都实例化新标记，只需使用其

Instead of instantiating a new marker on every update, you could simply modify its position using its setLatLng() method.

通常的实现是使用全局"标记变量(仅在更新函数之外的范围内就足够了)，在第一次迭代时将其初始化为Marker，然后无需实例化新变量，只需修改其位置即可

The usual implementation is to use a "global" marker variable (just in a scope outside your update function is enough), initialize it to a Marker on your first iteration, then instead of instantiating a new one, simply modify its position.

可能比较棘手的部分是同时管理多个标记.您需要某种识别方式才能知道要更新哪个.我认为这是您的value.name:

The possibly slightly trickier part is to manage several markers at the same time. You need some sort of identification mean to know which one to update. I assume it is your value.name:

var markers = {}; // Dictionary to hold your markers in an outer scope.

function ajaxCallback(response) {
  var equipmentDetails = response.data.filters;
  $.each(equipmentDetails, function(i, value) {
    var id = value.name;
    var latLng = [value.latitude, value.longitude];
    var popup = '<b><span> Name:</span>' + id + '</b>';

    if (!markers[id]) {
      // If there is no marker with this id yet, instantiate a new one.
      markers[id] = L.marker(latLng).addTo(map).bindPopup(popup);
    } else {
      // If there is already a marker with this id, simply modify its position.
      markers[id].setLatLng(latLng).setPopupContent(popup);
    }
  });
}

$.ajax({
  url: details,
  method: 'get'
}).done(ajaxCallback);

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