Question

我正在编写一个程序，一个记录用户位置的Web服务。该程序使用地理定位来查找用户，并在检索到该位置后继续记录该位置。由于地理定位使用回调函数来获取位置，因此程序在具有该位置之前无法继续。问题是我不能在地理定位功能中继续该程序，因为需要其他变量。所以我所做的是geoolcaion函数使用以下函数显示网页上的位置

function geoFindMe(){
  navigator.geolocation.getCurrentPosition(success, error, geo_options);
function success(position) {
var latitude = position.coords.latitude;
 var longitude = position.coords.longitude;
 var altitude = position.coords.altitude;
 var accuracy = position.coords.accuracy;
 var time = getTime();
 //post the everything somewhere and then the callback function will fetch the info 
 //may use var time = position.timestamp;
 $("#result").append(time + " " + latitude + " " + longitude); 
}

function error(error) {
 alert("Unable to retrieve your location due to "+error.code + " : " + error.message);
 }//there was a semicolon here

var geo_options = {
 enableHighAccuracy: true,
 maximumAge : 30000,
 timeout : 27000
 };
}

此函数由以下代码

调用

 geoFindMe(function successful(){
        //first call geoFindMe function then call successful as a callback
        //the function will retrieve the information that was displayed by the geoFindMe on the webpage
            $("#result").hide();
            var currentLocation = document.getElementById('result');
            document.getElementById('result').innerHTML = "";
            var moved = hasMoved(previousLocation, currentLocation);
            var time = isItTime(moved, lastBuffer, 15);
            if(time){//its time to put the location in the buffer
                currentLocation = currentLocation + "#";// this way we will be able to differentiate between different locations
                charBuffer.wrap(currentLocation);
            }
            dump(stringArray, lastDump, true);
        });

我想要做的是一旦找到地理定位然后调用成功的函数，我试图做一个回调函数。问题是，由于某种原因，它正在跳过大部分成功的回调函数，并继续行转储（...）;有什么建议？也许我没有正确地写出成功的功能？非常感谢

Answer 1

您所要做的就是在geoFindMe函数中添加一个参数来接受回调。然后在成功函数中调用它

function geoFindMe(callback){
  navigator.geolocation.getCurrentPosition(success, error, geo_options);
  function success(position) {
     callback&&callback(); // Check if callback exists and then call it.
     var latitude = position.coords.latitude;
     var longitude = position.coords.longitude;
     var altitude = position.coords.altitude;
     var accuracy = position.coords.accuracy;
     var time = getTime();
     //post the everything somewhere and then the callback function will fetch the info 
     //may use var time = position.timestamp;
     $("#result").append(time + " " + latitude + " " + longitude); 
  }  
  function error(error) {
     alert("Unable to retrieve your location due to "+error.code + " : " + error.message);
  }//there was a semicolon here
  var geo_options = {
     enableHighAccuracy: true,
     maximumAge : 30000,
     timeout : 27000
  };
}

找到地理定位后使用回调

1 个答案: