問(wèn)題描述

我嘗試開發(fā)瀏覽器地理定位，但似乎地理定位在仍在搜索我的位置時(shí)會(huì)很快返回一個(gè)值.

I tried developing browser geolocation, but it seems geolocation quickly return a value when it is still searching for my location.

我的腳本示例:

function updateCoordinate() {
        navigator.geolocation.getCurrentPosition(
                function (position) {
                    setTimeout(function() {
                        var returnValue = {
                            latitude: position.coords.latitude,
                            longitude: position.coords.longitude
                        }
                        var serializeCookie = serialize(returnValue);
                        $.cookie('geolocation', serializeCookie);
                        return serializeCookie;
                    }, 5000);
                },
                function () {
                    alert('Sorry, we are failed to get your location')
                }, {timeout: 5000}
        )
    }

如果我們執(zhí)行這個(gè)腳本updateCoordinate，函數(shù)會(huì)返回undefined.但過(guò)了一會(huì)兒，如果我們檢查 cookie，它會(huì)正確設(shè)置坐標(biāo).

If we execute this script updateCoordinate, the function will return undefined. But after a moment if we check the cookie it set right the coordinate.

如何讓getCurrentPosition等到獲得精確坐標(biāo)后再返回值?

How to make getCurrentPosition waiting until get exact coordinate before returning the value?

推薦答案

使用回調(diào)，而不是超時(shí)，這會(huì)讓你遇到各種各樣的問(wèn)題.大致如下:

Use a callback, not a timeout which will end you up in all sorts of problems. Something along the lines of:

// Here you pass a callback function as a parameter to `updateCoordinate`.
updateCoordinate(function (cookie) {
  console.log(cookie);
});

function updateCoordinate(callback) {
    navigator.geolocation.getCurrentPosition(
      function (position) {
        var returnValue = {
          latitude: position.coords.latitude,
          longitude: position.coords.longitude
        }
        var serializeCookie = serialize(returnValue);
        $.cookie('geolocation', serializeCookie);

        // and here you call the callback with whatever
        // data you need to return as a parameter.
        callback(serializeCookie);
      }
    )
}

這篇關(guān)于JS Geolocation 等到成功再返回值的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！