如何確認何時完成多個AJAX呼叫？

Question

$(document).ready(function() { 
    $("#list1").jqGrid({ 
     url: 'example1.php', 
     /*balabala...*/ 
     gridComplete: function() { 

     } 
    }); 

    $("#list2").jqGrid({ 
     url: 'example2.php', 
     /*balabala...*/ 
     gridComplete: function() { 

     } 
    }); 

    /*I want to do something here, but the above grids must be both complete first.*/ 
    Something... 
}); 

我應該怎麼辦？謝謝！

Answer 1

最簡單的方法是把你的gridComplete回調「東西」，但有兩個回調檢查另一個已完成。沿着這些路線的東西：

function do_something_wonderful() { 
    // This is the awesome stuff that you want to 
    // execute when both lists have loaded and finished. 
    // ... 
} 

var one_done = false; 
function done_checker() { 
    if(one_done) { 
     // The other one is done so we can get on with it. 
     do_something_wonderful(); 
    } 
    one_done = true; 
} 

$("#list1").jqGrid({ 
    //blah blah blah 
    gridComplete: done_checker 
}); 
$("#list2").jqGrid({ 
    //blah blah blah 
    gridComplete: done_checker 
}); 

這很好地延伸到兩個以上的列表與幾個小的修改：

• 使用var how_many_done = 0;代替one_done。
• 做一個++how_many_done;，而不是one_done = true;並將其移動到的done_checker頂部。
• 更換if(one_done)與if(how_many_done == number_of_tasks)其中number_of_tasks是你有多少AJAX任務都有。

普通版看起來有點像這樣：

var number_of_tasks = 11; // Or how many you really have. 
var how_many_done = 0; 
function done_checker() { 
    ++how_many_done; 
    if(how_many_done == number_of_tasks) { 
     // All the AJAX tasks have finished so we can get on with it. 
     do_something_wonderful(); 
    } 
} 

一個更好的版本將在一個封閉包的狀態：

var done_checker = (function(number_of_tasks, run_when_all_done) { 
    var how_many_done = 0; 
    return function() { 
     ++how_many_done; 
     if(how_many_done == number_of_tasks) { 
      // All the AJAX tasks have finished so we can get on with it. 
      run_when_all_done(); 
     } 
    } 
})(do_something_wonderful, 11); 

Answer 2

你目前應該使用jquery deferred objects是。 ！