ArcGIS JavaScript API使用Promise进行公交换乘查询及结果绘制

来源：互联网发布：网络神曲2016 编辑：程序博客网时间：2024/04/30 10:57
两个方法，一个用于根据站点名称获得站点的点对象（包含坐标信息），另一个是根据站点信息进行线路的处理及展示。代码如下：
        /**         * 获取公交站点         * @param  {[type]} stationName [站点名称]         * @param  {[type]} lineName    [站点所在线路名称]         * @return {[type]}             [Point，包含坐标]         */        getStationPoint:function(stationName,lineName){            var p = new Promise(function(resolve,reject){                var queryTask = new QueryTask(this.busStationLayerURLProperty);                var query = new Query();                query.returnGeometry=true;                var where=this.belongLineNameProperty+"='"+lineName+"' and "+this.stationNameProperty+"= '"+stationName+"'";                query.where = where;                query.outFields=["*"];                queryTask.execute(query).then(function(result){                    if(1!=result.features.length){                        reject("bad result");                    }else {                        resolve(result.features[0].geometry);                    }                }.bind(this));            }.bind(this));            return p;        },                /**         * 获取及显示换乘线路         * @param  {[type]} lineNames [线路名，如有多条，以逗号隔开]         * @return {[type]}           [description]         */        getChangeLine: function(lineNames) {            _this = this;            var queryTask = new QueryTask(_this.busLineLayerURLProperty);            var query = new Query();            query.returnGeometry = true;            var where = "";            for (var i = 0; i < lineNames.length; i++) {                if (i == 0) {                    where = _this.lineNameProperty + "= '" + lineNames[i] + "'";                } else                    where = where + " or " + _this.lineNameProperty + "= '" + lineNames[i] + "'";            }            //获取出发站、到达站、换乘站            var startStation = dom.byId(_this.startStationId).getElementsByTagName("input")[0].value;            var endStation = dom.byId(_this.endStationId).getElementsByTagName("input")[0].value;            var changeStation = _this.currentChangeStation;            query.where = where;            query.outFields = ["*"];            queryTask.execute(query, function(lines) {                var numLine = lines.features.length;                if (numLine > 1) {                    var startLine; //第一条线路Polyline的乘车区间段                    var endLine;  //第二条线路Polyline的乘车区间段                    var firstLine;  //第一条线路Polyline对象                    var secondLine;  //第二条线路Polyline对象                    var lineName1 = lineNames[0]; //第一条线路名                    var lineName2 = lineNames[1];  //第二条线路名                    for (var i = 0; i < 2; i++) {                        if (lines.features[i].attributes[_this.lineNameProperty] === lineName1) {                            firstLine=lines.features[i].geometry;                            Promise //根据站点名获取站点（Point），两个站点都获取完成后，进行乘车区间切割                            .all([_this.getStationPoint(changeStation,lineName1),_this.getStationPoint(startStation,lineName1)])                                                  .then(                                function(stations){                                    console.log("resolved start");                                    if(2==stations.length){                                        startLine = _this.getCutLine(stations[0], stations[1], firstLine); //切割乘车区间                                        if (startLine) { //绘制乘车区间                                            var graphicS = new Graphic(startLine);                                            graphicS.setSymbol(_this.simpleLineSymbol);                                            _this.graphicLayer.add(graphicS);                                        }                                    }                                }                                );                        } else {                            secondLine= lines.features[i].geometry;                            Promise                            .all([_this.getStationPoint(changeStation,lineName2),_this.getStationPoint(endStation,lineName2)])                            .then(                                function(stations){                                    console.log("resolved end");                                    endLine = _this.getCutLine(stations[0], stations[1], secondLine);                                    if (endLine) {                                        var graphicE = new Graphic(endLine);                                        graphicE.setSymbol(_this.simpleLineSymbol);                                        _this.graphicLayer.add(graphicE);                                    }                                }                                );                        }                    }                    //合并线路，获得外接矩形范围并显示                    var unionGeometry = geometryEngine.union(lines.features[0].geometry,lines.features[1].geometry);                    var newExtent = unionGeometry.getExtent();                    _this.map.setExtent(newExtent.expand(2));                    console.log("OK");                } else {                    error("查找的换乘线路少于两条，无法获取线路！");                    return false;                }            });        },
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