我有一个很简单的JS使用navigator。geolocation。getcurrentposition jammy。
$(document).ready(function(){
$("#business-locate, #people-locate").click(function() {
navigator.geolocation.getCurrentPosition(foundLocation, noLocation);
});
navigator.geolocation.getCurrentPosition(foundLocation, noLocation);
function foundLocation(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
var userLocation = lat + ', ' + lon;
$("#business-current-location, #people-current-location").remove();
$("#Near-Me")
.watermark("Current Location")
.after("<input type='hidden' name='business-current-location' id='business-current-location' value='"+userLocation+"' />");
$("#people-Near-Me")
.watermark("Current Location")
.after("<input type='hidden' name='people-current-location' id='people-current-location' value='"+userLocation+"' />");
}
function noLocation() {
$("#Near-Me").watermark("Could not find location");
$("#people-Near-Me").watermark("Could not find location");
}
})//end DocReady
基本上，这里发生的事情是我们得到当前位置，如果它得到了，两个“水印”被放置在两个字段中，表示“当前位置”，两个隐藏字段被创建，并使用latong数据作为它们的值(它们在开始时被删除，这样它们就不会每次都重复)。还有两个按钮，它们有一个点击功能，做同样的事情。
不幸的是，每隔三次左右，它就会奏效。
这里有什么问题?
我终于找到了一个工作版本的firefox, chrome和默认导航器在android(仅4.2测试):
function getGeoLocation() {
var options = null;
if (navigator.geolocation) {
if (browserChrome) //set this var looking for Chrome un user-agent header
options={enableHighAccuracy: false, maximumAge: 15000, timeout: 30000};
else
options={maximumAge:Infinity, timeout:0};
navigator.geolocation.getCurrentPosition(getGeoLocationCallback,
getGeoLocationErrorCallback,
options);
}
}
以下是我的解决方案，感谢一个闭包:
function geoloc(success, fail){
var is_echo = false;
if(navigator && navigator.geolocation) {
navigator.geolocation.getCurrentPosition(
function(pos) {
if (is_echo){ return; }
is_echo = true;
success(pos.coords.latitude,pos.coords.longitude);
},
function() {
if (is_echo){ return; }
is_echo = true;
fail();
}
);
} else {
fail();
}
}
function success(lat, lng){
alert(lat + " , " + lng);
}
function fail(){
alert("failed");
}
geoloc(success, fail);
截至2020年年中，这里的答案都没有提供任何解释，只是黑客攻击或猜测。
正如@Coderer在我之前指出的，安全上下文(https)是今天需要的，所以在越来越多的设备上，地理定位在普通http下根本不起作用:
安全上下文
此特性仅在安全上下文中(HTTPS)以及部分或所有支持的浏览器中可用。
getCurrentPosition()(和watchPosition()更适合这里)的第三个参数是PositionOptions对象，由以下属性组成:
enableHighAccurancy (default false): if set to true, response is slower and more accurate. If you got timeout errors, keep this to false. If the accurancy is low, set it to true. In my tests the accurancy varies and on some devices it has no effect. On other devices setting true may cause surprisingly quick battery depletion.
timeout (default infinity): milliseconds before the API gives up and calls the error handler (the second parameter). Today most mobile devices with geolocation enabled and permission granted for the browser/page get the value with reasonable accurancy within a second. When the geolocation service is not available, alternative method like geo IP may be used, the delay can be many seconds and the precision usually ranges from questionable to useless.
maximumAge (default 0): milliseconds when cached value is valid, the device may decide to use valid cached data instead of sensor measure. I usually set this to non-zero values with slowly moving devices (like walking with mobile phone). On static devices, Infinity can be set to avoid consequent reading errors.
正如@YoLoCo在我之前指出的那样，getCurrentPosition()和watchPosition()会干扰，我在2020年确认了他的结果。通常，使用watchPosition代替getCurrentPosition周期性调用。
