How to decide between _init and _create in jQuery UI widget?
I think I understand the difference between _create
and _init
in widget definitions (see for instance this question), but I'm still not certain about the purpose for the distinction. What sorts of setup tasks go in _create()
or in _init()
? What goe开发者_如何学运维s wrong if the widget author chooses the wrong one?
From:
- http://forum.jquery.com/topic/jquery-ui-1-8-use-of-init
- http://www.erichynds.com/jquery/tips-for-developing-jquery-ui-widgets/
- http://jqueryui.com/demos/dialog/
Use
_create
to build and inject markup, bind events, etc. Place default functionality in_init()
. The dialog widget, for example, provides anautoOpen
parameter denoting whether or not the dialog should be open once the widget is initialized; a perfect spot for_init()
!
Also:
The widget factory automatically fires the
_create()
and_init()
methods during initialization, in that order. At first glance it appears that the effort is duplicated, but there is a sight difference between the two. Because the widget factory protects against multiple instantiations on the same element,_create()
will be called a maximum of one time for each widget instance, whereas_init()
will be called each time the widget is called without arguments...
If the author uses _init()
when _create()
should have been coded, the result will be that the code in _init()
will be executed once per widget instantiation.
Short answer here: _create() will be executed when you run your jquery-ui plugin for the first time, like $xx.your-plugin(your options); _init() will be executed first and after the first time when your code runs into $xx.your-plugin(your options);
As there are some code in jquery-ui.custom.js like this:
var instance = $.data( this, fullName );
if ( instance ) {
instance.option( options || {} )._init();
}
So, if you draw a chart with jquery-ui plugin, after it's drawn out, then you want to use new data to update it, you need to do this in _init() to update your chart. If you just display something and won't update them totally, _create() will meet your needs.
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