jQuery UI Widget(1.8.1)工作原理--转载

/*!
* jQuery UI Widget 1.8.1
*
* Copyright (c) 2010 AUTHORS.txt (http://jqueryui.com/about)
* Dual licensed under the MIT (MIT-LICENSE.txt)
* and GPL (GPL-LICENSE.txt) licenses.
*
* http://docs.jquery.com/UI/Widget
*/
(function( $ ) {var _remove = $.fn.remove;$.fn.remove = function( selector, keepData ) {
return this.each(function() {
if ( !keepData ) {
if ( !selector || $.filter( selector, [ this ] ).length ) {
$( "*", this ).add( this ).each(function() {
$( this ).triggerHandler( "remove" );
});
}
}
//dom元素在被删除前，触发一下remove事件，jquery框架本身没有对元素删除绑定事件
return _remove.call( $(this), selector, keepData );
});
};$.widget = function( name, base, prototype ) {
var namespace = name.split( "." )[ 0 ],
fullName;
name = name.split( "." )[ 1 ];
fullName = namespace + "-" + name;
//比如ui.tab,上面的name='tab';fullName='ui-tab'; if ( !prototype ) {
prototype = base;
base = $.Widget;
}
//如果没有prototype,那么prototype就是base参数,实际base默认为$.Widget // create selector for plugin
$.expr[ ":" ][ fullName ] = function( elem ) {
return !!$.data( elem, name );
}; $[ namespace ] = $[ namespace ] || {};//是否有命名空间
$[ namespace ][ name ] = function( options, element ) {//根据上面的例子，即初始化了$.ui.tab=func
// allow instantiation without initializing for simple inheritance
if ( arguments.length ) {
this._createWidget( options, element );
}
}; var basePrototype = new base();//初始化，一般都是调用了new $.Widget()
// we need to make the options hash a property directly on the new instance
// otherwise we'll modify the options hash on the prototype that we're
// inheriting from
// $.each( basePrototype, function( key, val ) {
// if ( $.isPlainObject(val) ) {
// basePrototype[ key ] = $.extend( {}, val );
// }
// });
basePrototype.options = $.extend( {}, basePrototype.options );//初始化options值，注意不需要深度拷贝
$[ namespace ][ name ].prototype = $.extend( true, basePrototype, {
namespace: namespace,
widgetName: name,
widgetEventPrefix: $[ namespace ][ name ].prototype.widgetEventPrefix || name,
widgetBaseClass: fullName
}, prototype );
//为新的ui模块创建原型，使用深度拷贝，在basePrototype上扩展一些模块基本信息，在扩展prototype,比如ui.tabs.js中就是tab的拥有各种方法的大对象 $.widget.bridge( name, $[ namespace ][ name ] );//将此方法挂在jQuery对象上
};$.widget.bridge = function( name, object ) {
$.fn[ name ] = function( options ) {
var isMethodCall = typeof options === "string",
args = Array.prototype.slice.call( arguments, 1 ),
returnValue = this;
//如果第一个参数是string类型，就认为是调用模块方法
//剩下的参数作为方法的参数，后面会用到 // allow multiple hashes to be passed on init
options = !isMethodCall && args.length ?
$.extend.apply( null, [ true, options ].concat(args) ) :
options;
//可以简单认为是$.extend(true,options,args[0],...),args可以是一个参数或是数组 // prevent calls to internal methods
if ( isMethodCall && options.substring( 0, 1 ) === "_" ) {
return returnValue;
}
//开头带下划线的方法都是私有方法，不让调用 if ( isMethodCall ) {//如果是调用函数
this.each(function() {
var instance = $.data( this, name ),//得到实例，实例作为一个数据和元素关联上
methodValue = instance && $.isFunction( instance[options] ) ?
instance[ options ].apply( instance, args ) ://如果实例和方法均存在，调用方法，把args作为参数传进去
instance;//否则返回undefined
if ( methodValue !== instance && methodValue !== undefined ) {//如果methodValue不是jquery对象也不是undefined
returnValue = methodValue;
return false;//跳出each，一般获取options的值会走这个分支
}
});
} else {//不是函数调用的话
this.each(function() {
var instance = $.data( this, name );
if ( instance ) {//实例存在
if ( options ) {//有参数
instance.option( options );//调用option函数，一般是设置状态之类的操作
}
instance._init();//再次调用此函数，根据options调整
} else {
$.data( this, name, new object( options, this ) );
//没有实例的话，给元素绑定一个实例。注意这里的this是dom，object是模块类
}
});
} return returnValue;//返回，有可能是jquery对象，有可能是其他值
};
};$.Widget = function( options, element ) {//所有模块的基类
// allow instantiation without initializing for simple inheritance
if ( arguments.length ) {//如果有参数，调用初始化函数
this._createWidget( options, element );
}
};$.Widget.prototype = {
widgetName: "widget",
widgetEventPrefix: "",
options: {
disabled: false
},//上面的属性会在创建模块时被覆盖
_createWidget: function( options, element ) {
// $.widget.bridge stores the plugin instance, but we do it anyway
// so that it's stored even before the _create function runs
this.element = $( element ).data( this.widgetName, this );//缓存实例，保存jquery对象
this.options = $.extend( true, {},
this.options,
$.metadata && $.metadata.get( element )[ this.widgetName ],
options );//参数处理 var self = this;
this.element.bind( "remove." + this.widgetName, function() {
self.destroy();
});//注册销毁事件 this._create();//创建
this._init();//初始化
},
_create: function() {},
_init: function() {}, destroy: function() {//销毁模块：去除绑定事件、去除数据、去除样式、属性
this.element
.unbind( "." + this.widgetName )
.removeData( this.widgetName );
this.widget()
.unbind( "." + this.widgetName )
.removeAttr( "aria-disabled" )
.removeClass(
this.widgetBaseClass + "-disabled " +
"ui-state-disabled" );
}, widget: function() {//返回jquery对象
return this.element;
}, option: function( key, value ) {//设置选项函数
var options = key,
self = this; if ( arguments.length === 0 ) {
// don't return a reference to the internal hash
return $.extend( {}, self.options );//返回一个新的对象，不是内部数据的引用
} if (typeof key === "string" ) {
if ( value === undefined ) {
return this.options[ key ];//取值
}
options = {};
options[ key ] = value;//设置值
} $.each( options, function( key, value ) {
self._setOption( key, value );//调用内部的_setOption
}); return self;
},
_setOption: function( key, value ) {
this.options[ key ] = value; if ( key === "disabled" ) {//增加或是去除className
this.widget()
[ value ? "addClass" : "removeClass"](
this.widgetBaseClass + "-disabled" + " " +
"ui-state-disabled" )
.attr( "aria-disabled", value );
} return this;
}, enable: function() {
return this._setOption( "disabled", false );
},
disable: function() {
return this._setOption( "disabled", true );
}, _trigger: function( type, event, data ) {
var callback = this.options[ type ]; event = $.Event( event );
event.type = ( type === this.widgetEventPrefix ?
type :
this.widgetEventPrefix + type ).toLowerCase();
data = data || {}; // copy original event properties over to the new event
// this would happen if we could call $.event.fix instead of $.Event
// but we don't have a way to force an event to be fixed multiple times
if ( event.originalEvent ) {//把原始的event属性重新赋到event变量上
for ( var i = $.event.props.length, prop; i; ) {
prop = $.event.props[ --i ];
event[ prop ] = event.originalEvent[ prop ];
}
} this.element.trigger( event, data ); return !( $.isFunction(callback) &&
callback.call( this.element[0], event, data ) === false ||
event.isDefaultPrevented() );
}
};})( jQuery );