接受请求时的地理位置反馈

Question

地理位置的实现是相当不错的,并且几乎没有什么步骤可以观察,但我猜这只是缺少的东西.我无法看到用户是否接受了请求(在我获得位置对象之前),我不知道用户是否只是忽略了我的请求(在我的超时期间)或者请求是否丢失(并且失败回调没有得到)无缘无故地说.

当用户接受请求时设置时间戳会很有用,我找不到任何能给我这种响应的东西.

Answer 1

它是Geolocation API的一部分:

// navigator.geolocation.getCurrentPosition(successCallback, errorCallback, options);
navigator.geolocation.getCurrentPosition(
  function(position){
    //do something with position;
  }, function(){
    //handle condition where position is not available
    //more specifically you can check the error code...
    //error.code == 1
    if(error.PERMISSION_DENIED){
      alert("you denied me! ");
    }
});

如果指定errorCallback ...则可以跟踪用户是否拒绝提供访问权限.

可能的错误代码包括:

error.PERMISSION_DENIED    (numeric value 1)
error.POSITION_UNAVAILABLE (numeric value 2)
error.TIMEOUT              (numeric value 3)

Answer 2

基于我对你所追求的事物的新认识,你想要这样的东西.(经测试:在Opera中工作,Firefox 3.6和Chrome 8 - 没那么多(我需要更多时间来调试))

场景: 页面尝试获取位置...但是用户完全忽略了提示,因此没有(接受或拒绝),因为从未发送过该位置的请求,也没有超时!

基于此,您可能希望添加自己的逻辑来处理此场景.为了这个例子,我将使用自己的"包装器"方法进行原型设计.(对于挑剔 - 我不是在使用全局变形等等.我只是想让一些东西起作用)

navigator.geolocation.requestCurrentPosition = function(successCB, errorCB, timeoutCB, timeoutThreshold, options){
  var successHandler = successCB;
  var errorHandler = errorCB;
  window.geolocationTimeoutHandler = function(){
    timeoutCB();
  }
  if(typeof(geolocationRequestTimeoutHandler) != 'undefined'){
    clearTimeout(window['geolocationRequestTimeoutHandler']);//clear any previous timers
  }
  var timeout = timeoutThreshold || 30000;//30 seconds
  window['geolocationRequestTimeoutHandler'] = setTimeout('geolocationTimeoutHandler()', timeout);//set timeout handler
  navigator.geolocation.getCurrentPosition(
    function(position){
      clearTimeout(window['geolocationRequestTimeoutHandler']);
      successHandler(position);
    },
    function(error){
      clearTimeout(window['geolocationRequestTimeoutHandler']);
      errorHandler(error);
    },
     options
  );
};
function timeoutCallback(){
  alert('Hi there! we are trying to locate you but you have not answered the security question yet.\n\nPlease choose "Share My Location" to enable us to find you.');
}
function successCallback(position){
  var msg = '';
  msg += 'Success! you are at: ';
  msg += '\nLatitude: ' + position.coords.latitude;
  msg += '\nLongitude: ' + position.coords.longitude;
  msg += '\nAltitude: ' + position.coords.altitude;
  msg += '\nAccuracy: ' + position.coords.accuracy;
  msg += '\nHeading: ' + position.coords.heading;
  msg += '\nSpeed: ' + position.coords.speed;
  alert(msg);
}
function errorCallback(error){
  if(error.PERMISSION_DENIED){
    alert("User denied access!");
  } else if(error.POSITION_UNAVAILABLE){
    alert("You must be hiding in Area 51!");
  } else if(error.TIMEOUT){
    alert("hmmm we timed out trying to find where you are hiding!");
  }
}
navigator.geolocation.requestCurrentPosition(successCallback, errorCallback, timeoutCallback, 7000, {maximumAge:10000, timeout:0});

概念是首先设置计时器(如果未设置,则默认为30秒).如果用户在计时器到期之前没有执行任何操作,则会调用timeoutCallback.

笔记:

1. 一些用户界面(例如iPhone/iPad/iPod Safari)可能会出现允许/拒绝提示模式 - 因此用户在选择某些内容之前无法真正继续(我建议让这些用户单独使用并让默认用户界面处理
2. 如果用户允许请求(延迟),超时可能仍会在响应返回之前触发 - 我认为您无法对此做任何事情
3. 上面的代码只是一个例子......它需要清理.

Answer 3

在FF 3.5,Opera 10.6,Chrome8,IE6-8中测试成功.

var succeed = function(obj) {
    navigator.geolocation.received = true;
    !navigator.geolocation.timedout?alert('GOT YAH'):alert('GOT YAH but user was to slow'); 
};
var failed  = function(obj) { 
    navigator.geolocation.received = true;
    !navigator.geolocation.timedout?alert('just failed'):alert('failed and user was to slow as well, tzz ._.'); 
};
var timedout    = function() {
    navigator.geolocation.timedout = true; // could be used for other callbacks to trace if its timed out or not
    !navigator.geolocation.received?alert('Request timed out'):null;    
}

// Extend geolocation object
if ( navigator.geolocation  ) {
    navigator.geolocation.retrievePermission = function retrievePermission(succeed,failed,options,timeout) {
        this.received = false;              // reference for timeout callback
        this.timedout = false;              // reference for other callbacks
        this.getCurrentPosition.apply(this,arguments);  // actual request

        // Trigger timeout with its function; default timeout offset 5000ms
        if ( timeout ) {
            setTimeout(timeout.callback,timeout.offset || 5000);
        }
    }

    // New location request with timeout callback
    navigator.geolocation.retrievePermission(succeed,failed,{},{
        offset: 10000, // miliseconds
        callback: timedout  
    });

// Awesome thingy is not implemented
} else {
    alert('geolocation is not supported');
}

通过该解决方法,我们知道请求是否超时,即使后续调用后成功/失败回调.