返回介绍

callbacks.lock()

发布于 2017-09-11 字数2787 浏览 920 评论 0

所属分类:回调对象

callbacks.lock()返回: Callbacks

描述: 锁定回调列表的当前状态。

  • 添加的版本: 1.7callbacks.lock()

    • 这个方法不接受任何参数

此方法返回绑定它的那个回调对象(this).

如果回调对象被创建,用"memory"标志作为它的参数,绑定函数可能会在回调列表中被锁定后增加并且触发。

例子:

Example:
callbacks.lock() 锁定一个回调列表,以避免进一步的修改列表状态 :

// a sample logging function to be added to a callbacks list
var foo = function( value ) {
  console.log( "foo:" + value );
};
 
var callbacks = $.Callbacks();
 
// add the logging function to the callback list
callbacks.add( foo );
 
// fire the items on the list, passing an argument
callbacks.fire( "hello" );
// outputs "foo: hello"
 
// lock the callbacks list
callbacks.lock();
 
// try firing the items again
callbacks.fire( "world" );
 
// as the list was locked, no items
// were called, so "world" isn"t logged

Example: Use callbacks.lock() to lock a callback list with “memory,” and then resume using the list:

<!DOCTYPE html>
<html>
<head>
  <script src="http://cdn.bootcss.com/jquery/1.11.2/jquery.min.js"></script>
</head>
<body>
  <div id="log"></div>
<script>// simple function for logging results
var log = function( value) {
  $( "#log" ).append( "<p>" + value + "</p>" );
};
 
// two sample functions to be added to a callbacks list
var foo = function( value ) {
  log( "foo: " + value );
};
var bar = function( value ) {
  log( "bar: " + value );
};
 
// create the callbacks object with the "memory" flag
var callbacks = $.Callbacks( "memory" );
 
// add the foo logging function to the callback list
callbacks.add( foo );
 
// fire the items on the list, passing an argument
callbacks.fire( "hello" );
// outputs "foo: hello"
 
// lock the callbacks list
callbacks.lock();
 
// try firing the items again
callbacks.fire( "world" );
// as the list was locked, no items were called,
// so "foo: world" isn't logged
 
// add the foo function to the callback list again
callbacks.add( foo );
 
// try firing the items again
callbacks.fire( "silentArgument" );
// outputs "foo: hello" because the argument value was stored in memory
 
// add the bar function to the callback list
callbacks.add( bar );
 
callbacks.fire( "youHadMeAtHello" );
// outputs "bar: hello" because the list is still locked,
// and the argument value is still stored in memory
</script>
 
</body>
</html>

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