Question

我正在尝试设置一个变量来保存纬度和经度变量以在Google地图上绘制（我试图让它稍后设置，以后我可以添加到集合中）。我正在运行控制台长测试，发现我的函数中的变量是设置坐标。我怎么能这样做？（对不起，我还是JavaScript和Backbone.Js的新手）

    var Area = Backbone.View.extend({
    el: '#load',

    initialize: function(){
        //this.getLocation();
        this.canvasId = 'map';
        this.area = '<h2>Area of BAC</h2><div id="'+this.canvasId+'"></div>';
    },

    render: function(){
        this.$el.html(this.area);
        this.getLocation();
        console.log(this.lat+' '+this.lng+' - Confirmed');
        //this.createMap(this.lat, this.lng);
        //google.maps.event.addDomListener(window, 'load', this.createMap);

    },

    createMap: function(lat, lng){
        //var mlat = lat;
        //var mlong = lng;
        //alert(lat+' '+lng);
        var mapOptions = {
            center: new google.maps.LatLng(40.7430473, -74.1777488),
            //center: new google.maps.LatLng(mlat, mlng),
            zoom: 15
        }
        var map = new google.maps.Map(document.getElementById(this.canvasId), mapOptions);
    },

    getLocation: function(){
        console.log('Test - getGeolocation');
        if(navigator.geolocation){
            //navigator.geolocation.getCurrentPosition(this.setLatLng);
            navigator.geolocation.getCurrentPosition(this.setLatLng);
        }else{
            alert('Either you have no internet connection or your browser is not supported');
        }
    },

    setLatLng: function(position){
        console.log('Test - setLatLng');
        this.lat = position.coords.latitude;
        console.log('Test - setLatLng-lat');
        this.lng = position.coords.longitude;
        console.log('Test - setLatLng-lng');
        console.log(this.lat+' '+this.lng);
    },

    throwErr: function(){
        alert('Cannot get coords');
    }

});

我的控制台日志：

Test - getGeolocation Area.js:32
undefined undefined - Confirmed Area.js:13
Test - setLatLng Area.js:42
Test - setLatLng-lat Area.js:44
Test - setLatLng-lng Area.js:46
19.7180872 -89.0860836

Answer 1

猜猜：问题似乎与this引用有关。

将getLocation方法更新为以下内容：

getLocation: function(){
    var self = this;
    console.log('Test - getGeolocation');
    if(navigator.geolocation){
        //navigator.geolocation.getCurrentPosition(this.setLatLng);
        navigator.geolocation.getCurrentPosition(function (position) {
            self.setLatLng(position);
        });
    }else{
        alert('Either you have no internet connection or your browser is not supported');
    }
},

Backbone Js - 设置地理位置变量[未定义变量]

1 个答案: