我有以下代码:
/*
* converts a string to geolocation and returns it
*/
function stringToLatLng(string){
if(typeof string == "string"){
geocoder = new google.maps.Geocoder();
geocoder.geocode( { 'address': string}, function(results, status) {
if (status == google.maps.GeocoderStatus.OK) {
console.log("LatLng: "+results[0].geometry.location);
return results[0].geometry.location;
} else {
console.log("Geocode was not successful for the following reason: " + status);
}
});
}
}
LatLng 将正确的位置打印到控制台,但是当我这样写时:
var pos = stringToLatLng('New York');
console.log(pos);
我得到未定义
返回。这是为什么?谢谢
最佳答案
类似这样的:
function stringToLatLng(strloc, callback){
if(typeof string == "string"){
geocoder = new google.maps.Geocoder();
geocoder.geocode( { 'address': strloc}, function(results, status) {
if (status == google.maps.GeocoderStatus.OK) {
callback.call({}, results[0].geometry.location);
} else {
console.log("Geocode was not successful for the following reason: " + status);
}
});
}
}
stringToLatLng('New York', function(pos){
console.log(pos);
});
在您的代码中,当您返回时,您实际上是从 function(results, status){..} 函数返回,而不是 stringToLatLng 函数,正如注释中所述,它是一个异步调用,因此您必须使用回调.
关于javascript - 为什么这个变量未定义或未返回?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12467690/