javascript - 如何解决 “cannot call method … of undefined” 错误？

Question

    function calcRoute() {
        var start = document.getElementById("start_").value;
        var end = document.getElementById("end_").value;
        var request = {
            origin: start,
            destination: end,
            travelMode: google.maps.TravelMode.DRIVING
        };
        directionsService.route(request, function (response, status) {
            if (status == google.maps.DirectionsStatus.OK) {
                directionsDisplay.setDirections(response);
            }
        });
    }

在 Chrome 中给出一条错误消息:“未捕获的类型错误:无法调用未定义的方法‘setDirections’”。谁能建议解决这个问题？谢谢

Answer 1

你错过了(全局变量)

//var directionsService = new google.maps.DirectionsService();
var directionsDisplay = new google.maps.DirectionsRenderer({ 'map': map }); 

所以 directionsDisplay 是未定义的。