Question

我有每秒30秒向服务器发送当前坐标的jquery代码。它适用于具有良好数据覆盖信号的区域。但是，当信号不稳定时（数据覆盖可用且反复消失），它会崩溃。几次，应用程序只是在try ... catch部分没有任何警告的情况下崩溃。

我需要检查数据覆盖是否可用，然后不断向服务器发送坐标，否则只需继续检查，直到数据覆盖可用。

这是我的代码：

    <!DOCTYPE html>
<html>
  <head>


    <script type="text/javascript" charset="utf-8" src="cordova-2.0.0.js">
     </script>

     <script src="jquery-1.5.2.min.js"></script>
     <script src="main.js"></script>
      <script src="jquery.mobile-1.0a4.min.js"></script>
   <script>


    var netCoverage = false;
    var lat='';
    var lon='';


    document.addEventListener("deviceready", onDeviceReady, false);
    document.addEventListener("pause", onDeviceReady, false);






    function checkConnection() {
        var networkState = navigator.network.connection.type;

        var states = {};
        states[Connection.UNKNOWN]  = 0; //'Unknown connection';
        states[Connection.ETHERNET] = 1; //'Ethernet connection';
        states[Connection.WIFI]     = 2; //'WiFi connection';
        states[Connection.CELL_2G]  = 3; //'Cell 2G connection';
        states[Connection.CELL_3G]  = 4; //'Cell 3G connection';
        states[Connection.CELL_4G]  = 5; //'Cell 4G connection';
        states[Connection.NONE]     = 6; //'No network connection';

        //alert('Connection type: ' + states[networkState]);
        if(states[networkState]!=0 && states[networkState]!=6)
                netCoverage = true;
        else
                netCoverage = false;


         }//ends checking for network connection

    var watchID = null;


    function onDeviceReady() {


    checkConnection();







        // Get the most accurate position updates available on the
        // device.
        var options = { maximumAge:30000, enableHighAccuracy: true };
        watchID = navigator.geolocation.watchPosition(onSuccess,
                                                   onError, options);

          // Update compass every 3 seconds
        var watchID = null;
}
        // onError Callback receives a PositionError object
        //
        function onError(error) {
       alert('code: '+ error.code+'\n'+'message:'+ 
                                               error.message + '\n');
        }

$(document).ready(function() {

     /*****************************/
    (function worker() {
        try{                  

           if(netCoverage){             
                 $.ajax({url: 'http://www.myurl.com/add_position.php?&lat='
                 +lat+'&lon='+lon,
             success: function(data) {
            $("#geo_info").text(data);
            accIndex=0;//reset after submitting to server
              },
        error: function(request, error){
            $("#geo_info").text("Network error: "+error);
            $.ajax(this);
            return;
        },
        complete: function() {
        // Schedule the next request when the current one's complete
        setTimeout(worker, 30000);
        }
        });
        }//ends checking for connection
        else{
          $("#geo_info").text('Unknown or no network connection.');
          setTimeout(worker, 30000);      //After calling this 
         //method few times      in              weak data coverage,
          // the app crashes with no warning
        }
        }catch(err){

        $("#geo_info").text('ALMOST CRASHED, '+err.message);

             $.ajax(this);
        return;
        }


        })();

    /*************************************************/
});

    </script>
  </head>
  <body>
    <p id="geo_info">Watching geolocation...</p>
        <button onclick="clearWatch();">Clear Watch</button>


  </body>
</html>

Answer 1

为什么不听online＆amp; offline事件？

<强>在线

当应用程序联机时，此事件将触发，并且设备将连接到Internet。

document.addEventListener("online", yourCallbackFunction, false);

<强>离线

当应用程序脱机并且设备未连接到Internet时，事件将触发。

document.addEventListener("offline", yourCallbackFunction, false);

希望这对你有所帮助！

phonegap Jquery在请求之前检查数据连接

1 个答案: