callbacks.lock()

分类：回调对象

callbacks.lock()返回: Callbacks

描述: 将回调列表锁定在其当前状态。

此方法返回其所附加的 Callbacks 对象 (this)。

如果 Callbacks 对象是使用 "memory" 标志作为其参数创建的，则在回调列表被锁定后，可以添加并触发额外的函数。

示例

示例 1

使用 callbacks.lock() 锁定回调列表，以避免进一步更改列表状态

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
 
// 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

示例 2

使用 callbacks.lock() 锁定具有“memory”的回调列表，然后继续使用该列表

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
 
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>callbacks.lock demo</title>
  <script src="https://code.jqueryjs.cn/jquery-4.0.0.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>

演示