如何将 map.locate 与 Polymer 1.0/leaflet

本文介绍了如何将 map.locate 与 Polymer 1.0/leaflet-map 1.0 一起使用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我对 Polymer 和 Leaflet 的 web 组件都是新手.

I am new to both Polymer and Leaflet's web component.

我想要一个按钮来切换 Leaflet 提供的地理定位功能.在 Javascript/HTML/css 应用程序中使用 Leaflet 我会知道如何做到这一点，但我无法使用 Polymer 1.0 让它工作.

I would like to have a button that toggles the geolocation function given by Leaflet. Using Leaflet in a Javascript/HTML/css application I would know how to do this but I can't get it to work using Polymer 1.0.

这是我的地图元素.我调用 map.locate 的尝试在元素注册中被注释掉了:

Here is my map element. My attempt to call map.locate is commented out in the element registration:

<dom-module id="my-maps"> <style> ... </style> <template> <leaflet-map id="thismap" latitude="{{latitude}}" longitude="{{longitude}}" zoom="14"> <leaflet-geolocation enable-high-accuracy latitude="{{latitude}}" longitude="{{longitude}}" watch="true"> </leaflet-geolocation> <template is="dom-if" if="{{latitude}}"> <leaflet-marker latitude="{{latitude}}" longitude="{{longitude}}"> </leaflet-marker> </template> </leaflet-map> </template> <script> Polymer({ is: "my-maps", ready: function () { L.Icon.Default.imagePath="../../bower_components/leaflet/dist/images"; // **this.$.thismap.locate({setView: true}); // not working** } }); </script> </dom-module>

对于这个例子，我得到这个错误:无法读取未定义的属性thismap"

For this example I get this error: Cannot read property 'thismap' of undefined

如果我直接引用'this'(this.locate())，返回的错误是:this.locate 不是函数

If I refer to 'this' directly (this.locate()), the error returned is: this.locate is not a function

(此片段只是一个测试；理想情况下，定位函数将由来自 'geoButton' 元素的点击事件调用):

(this snippet is just a test; ideally the locate function would be called by a click event from the 'geoButton' element) :

<div flex> <ir-maps id="mymap" class="basemap" flex></ir-maps> <ir-geoButton class="geoButton" ></ir-geoButton> </div>

推荐答案

我的解决方案没有明确使用 map.locate.这不是必需的，因为 map.locate 是通过添加 leaflet-geolocation 元素启用的.

My solution does not use map.locate explicitly. This was not needed, as map.locate is enabled by adding the leaflet-geolocation element.

我从小册子地图元素中删除了纬度和经度属性(并添加了一些其他参数):

I removed the latitude and longitude property from the leaflet-map element (and added a few other parameters):

<leaflet-map id="nycmap" zoom="14" min-zoom="14" max-zoom="18" nozoomControl="true" noattributionControl:="false">

然后我在leaflet-map元素(leaflet-core.html)的注册中添加了一个一次性监听器，这样如果启用了地理定位，地图就会缩放到那个位置，如果没有，它会缩放到那个位置缩放到默认中心点.'geoB' 是一个切换地理定位功能的按钮:

Then I added a one-time listener to the registration of the leaflet-map element (leaflet-core.html), so that if geolocation is enabled, the map will zoom to that location, and if it is not it will zoom to a default center point. 'geoB' is a button that toggles the geolocation function:

map.addOneTimeEventListener('locationfound', function (e){ console.log("get to located found?"); map.setView(L.latLng(e.latitude, e.longitude), 14); var geo = document.getElementById('geoB'); var state = geo.classList.toggle('toggleState'); }, this); map.on('locationerror', function(e){ console.log("get to located error?"); map.setView(L.latLng(40.6889, -73.9444), 14); map.stopLocate(); }, this);

我向 Leaflet-map 元素添加了另一个功能，以便我可以将当​​前纬度和经度传递给元素并缩放到该点，点击地理定位按钮:

I added another function to the leaflet-map element so that I can pass the current latitude and longitude to the element and zoom to that point, on the click on the geolocation button:

setToPoint: function(newLat, newLong){ if (this.map && !this._ignoreViewChange) { this.async(function() { this.map.setView(L.latLng(newLat, newLong), this.zoom, {pan: {animate: true}}); this.map.invalidateSize(); }); } },

最后，这个函数在 geoButton 元素的事件监听器中被调用，它引用了 leaflet-geolocation 元素:

Finally, this function is called in an event listener in the geoButton element, which references the leaflet-geolocation element:

nycmap.setToPoint(locator.latitude, locator.longitude);