Question

从我的对象PolygonExtend我可以触发一些内部动作，如show和hide。这些行动似乎运作良好。但是，当我在click事件（google.maps.event.addDomListener）中运行相同的操作时，我得到一个“TypeError：this.name is undefined”。我怎样才能让它发挥作用？

jsFiddle here

var mapOptions = {
        center: new google.maps.LatLng(4.7102000, -74.0308118),
        zoom: 18,
        mapTypeId: google.maps.MapTypeId.ROADMAP
};

var map = new google.maps.Map(document.getElementById('map'), mapOptions);
var coords = [
  {lat: 4.711177836295898, lng: -74.03219819068909},
  {lat: 4.710354506576612, lng: -74.03219819068909},
  {lat: 4.710354506576612, lng: -74.03176367282867},
  {lat: 4.711177836295898, lng: -74.03176367282867}
];

function PolygonExtend(name, path) {
        //this.name = name;
        this.path = path;
        this.name =  new google.maps.Polygon({
                path: this.path,
        });

        this.show = function() {
            this.name.setMap(map);
        };
        this.hide = function() {
            this.name.setMap(null);
        };

        return this.name.setMap(map); // makes Polygon show when instantiated
}

a = new PolygonExtend('a', coords); // works and renders Polygon

a.hide(); // works, hides Polygon
a.show(); // works, makes Polygon visible again

var btn = document.getElementById('btn');
google.maps.event.addDomListener(btn, 'click', a.hide); // TypeError: this.name is undefined

Answer 1

正如上面的评论所述，这样做（如果你还没有尝试过这个解决方案）

function PolygonExtend(name, path) {
    //this.name = name;

    var self = this;
    this.name =  new google.maps.Polygon({
            path: path,
    });


    this.show = function() {
        self.name.setMap(map);
    };

    this.hide = function() {
        self.name.setMap(null);
    };

    return this.name.setMap(map); // makes Polygon show when instantiated
}

Answer 2

我不确定你要做什么。看起来像浪费代码，但看看这个：

function PointlessPolygon(map, coords){
  var t = this;
  this.map = map; this.coords = coords; this.showing = true;
  this.polygon = new google.maps.Polygon({paths:t.coords});
  this.show = function(){
    this.polygon.setMap(map); this.showing = true;
  };
  this.hide = function(){
    this.polygon.setMap(); this.showing = false;
  }
  this.polygon.setMap(map); // makes Polygon show when instantiated
}
var pp = new PointlessPolygon(map, coords);
var btn = document.getElementById('btn');
btn.addEventListener('click', function(){
  pp.showing ? pp.hide() : pp.show();
});

https://jsfiddle.net/evb4kmhw/2/

在单击事件中运行时，调用对象函数将被取消定义

2 个答案: