JavaScript for循环里边异步操作问题。

问题：（DRIVING.search是异步操作）

for循环中做异步操作会导致aDistances数组里边的数据全部都是从A_SHOP_INFO数组中最后一条数据获取的值。

var iIdx = 0;

for(var i=0, len=A_SHOP_INFO.length; i<len; i++){

    var shopInfo = A_SHOP_INFO[i];

    DRIVING.search(new AMap.LngLat(shopInfo.shop_location_long,shopInfo.shop_location_lat), new AMap.LngLat(myLnglat[0],myLnglat[1]), function(status, result){

        var distance                         = new O_DISTANCE_INFO();

        distance.distance                     = result.routes[0]["distance"];

        distance.shop_id                     = shopInfo.shop_id;

        distance.shop_location_long         = shopInfo.shop_location_long;

        distance.shop_location_lat             = shopInfo.shop_location_lat;

        distance.shop_location_format_str     = shopInfo.shop_location_format_str;

        // aDistances[aDistances.length] = distance;

        aDistances.push(distance);

        iIdx++;

        if(iIdx == A_SHOP_INFO.length){ // 与所有店铺导航距离计算完毕

            mylog("店铺距离数组");

            mylog("'"+JSON.stringify(aDistances)+"'");

            // 计算距离最近的店铺

            //mw_cal_min_distance(aDistances) ;

        }

    });

}

解决办法：可以用$.each来代替for循环

 //定义变量来计算算出了几个距离

 var iIdx = 0;

 //这里不使用for循环，是因为for循环中发生了异步请求之后，会导致所有异步请求成功之后的shopInfo都是最后一条数据。

 $.each(A_SHOP_INFO, function(i,shopInfo){

     DRIVING.search(new AMap.LngLat(shopInfo.shop_location_long,shopInfo.shop_location_lat), new AMap.LngLat(myLnglat[0],myLnglat[1]), function(status, result){

         var distance                         = new O_DISTANCE_INFO();

         distance.distance                     = result.routes[0]["distance"];

         distance.shop_id                     = shopInfo.shop_id;

         distance.shop_location_long         = shopInfo.shop_location_long;

         distance.shop_location_lat             = shopInfo.shop_location_lat;

         distance.shop_location_format_str     = shopInfo.shop_location_format_str;

         // aDistances[aDistances.length] = distance;

         aDistances.push(distance);

         iIdx++;

         if(iIdx == A_SHOP_INFO.length){ // 与所有店铺导航距离计算完毕

             mylog("店铺距离数组");

             mylog("'"+JSON.stringify(aDistances)+"'");

             // 计算距离最近的店铺

 //                mw_cal_min_distance(aDistances) ;

         }

     });

 });