引子
jQuery未过时，在一些中小网站中，jQuery还是发挥着瑞士军刀的作用。我们不能为了前后端分离而分离，一些很简单的需求，很简单的页面，freemarker+jQuery+bootstrap就能搞掂，奈何一定要搬动vue和react这些大刀呢？
今天和大家一起欣赏的，是一个不开源，或者说半开源的jQuery界面框架: easyui。
jQuery基础
先做一些铺垫。
jQuery可以把一个dom元素包装成一个jQuery对象
例如:
var obj = $('#div1')
要区分dom对象和jQuery对象。
jQuery插件的开发
jQuery为开发插件提拱了三种方法，分别是：
- jQuery.extend(object);为扩展jQuery类本身.为类添加新的方法。
- jQuery.fn.extend(object);给jQuery对象添加方法。
- 通过$.widget()应用jQuery UI的部件工厂方式创建
jQuery easyui多采用第二种：
$.fn.myPlugin = function() {
//在这里面,this指的是用jQuery选中的元素 example :$('a'),则this=$('a')
this.css('color', 'red');
}
$.fn其实就是jQuery对象的prototype:
jQuery.fn = jQuery.prototype ={
init: function( selector, context ){//....
//......
};
所以第二种方式就是以扩充jQuery原型的方式添加插件。
注意插件中this的指代：
$.fn.myPlugin = function() {
this.css('color', 'red'); //在这里面,this指的是用jQuery选中的元素
//对每个元素进行操作
return this.each(function() {
$(this).append(' ' + $(this).attr('href')); //此处的this指的是dom元素，需要用$()包装成jQuery对象。
}))
}
搞清楚上述函数的含义是阅读整个jQuery代码的关键。
- this.each()函数内部的this和外部的this是不同的，外面的是jQuery对象，内部的是dom对象
- this.each()的返回就是this，也就是外部的这个jQuery对象
- each()对外部的jQuery对象进行遍历，遍历原理见下：
jQuery的each实现原理：
// args is for internal usage only
each: function( obj, callback, args ) {
var value,
i = 0,
length = obj.length,
isArray = isArraylike( obj );
if ( args ) {
if ( isArray ) {
for ( ; i < length; i++ ) {
value = callback.apply( obj[ i ], args );
if ( value === false ) {
break;
}
}
} else {
for ( i in obj ) {
value = callback.apply( obj[ i ], args );
if ( value === false ) {
break;
}
}
}
// A special, fast, case for the most common use of each
} else {
if ( isArray ) {
for ( ; i < length; i++ ) {
value = callback.call( obj[ i ], i, obj[ i ] );
if ( value === false ) {
break;
}
}
} else {
for ( i in obj ) {
value = callback.call( obj[ i ], i, obj[ i ] );
if ( value === false ) {
break;
}
}
}
}
return obj;
},
jQuery easyui源码赏析
jQuery easyui每个组件为一个jQuery插件。
easyloader.js负责加载所有的插件。
(function(){
var modules = {
draggable:{
js:'jquery.draggable.js'
},
droppable:{
js:'jquery.droppable.js'
},
resizable:{
js:'jquery.resizable.js'
},
linkbutton:{
js:'jquery.linkbutton.js',
css:'linkbutton.css'
},
progressbar:{
js:'jquery.progressbar.js',
css:'progressbar.css'
},
pagination:{
js:'jquery.pagination.js',
css:'pagination.css',
dependencies:['linkbutton']
},
datagrid:{
js:'jquery.datagrid.js',
css:'datagrid.css',
dependencies:['panel','resizable','linkbutton','pagination']
},
treegrid:{
js:'jquery.treegrid.js',
css:'tree.css',
dependencies:['datagrid']
},
propertygrid:{
js:'jquery.propertygrid.js',
css:'propertygrid.css',
dependencies:['datagrid']
},
panel: {
js:'jquery.panel.js',
css:'panel.css'
},
window:{
js:'jquery.window.js',
css:'window.css',
dependencies:['resizable','draggable','panel']
},
dialog:{
js:'jquery.dialog.js',
css:'dialog.css',
dependencies:['linkbutton','window']
},
messager:{
js:'jquery.messager.js',
css:'messager.css',
dependencies:['linkbutton','window','progressbar']
},
layout:{
js:'jquery.layout.js',
css:'layout.css',
dependencies:['resizable','panel']
},
form:{
js:'jquery.form.js'
},
menu:{
js:'jquery.menu.js',
css:'menu.css'
},
tabs:{
js:'jquery.tabs.js',
css:'tabs.css',
dependencies:['panel','linkbutton']
},
splitbutton:{
js:'jquery.splitbutton.js',
css:'splitbutton.css',
dependencies:['linkbutton','menu']
},
menubutton:{
js:'jquery.menubutton.js',
css:'menubutton.css',
dependencies:['linkbutton','menu']
},
accordion:{
js:'jquery.accordion.js',
css:'accordion.css',
dependencies:['panel']
},
calendar:{
js:'jquery.calendar.js',
css:'calendar.css'
},
combo:{
js:'jquery.combo.js',
css:'combo.css',
dependencies:['panel','validatebox']
},
combobox:{
js:'jquery.combobox.js',
css:'combobox.css',
dependencies:['combo']
},
combotree:{
js:'jquery.combotree.js',
dependencies:['combo','tree']
},
combogrid:{
js:'jquery.combogrid.js',
dependencies:['combo','datagrid']
},
validatebox:{
js:'jquery.validatebox.js',
css:'validatebox.css'
},
numberbox:{
js:'jquery.numberbox.js',
dependencies:['validatebox']
},
searchbox:{
js:'jquery.searchbox.js',
css:'searchbox.css',
dependencies:['menubutton']
},
spinner:{
js:'jquery.spinner.js',
css:'spinner.css',
dependencies:['validatebox']
},
numberspinner:{
js:'jquery.numberspinner.js',
dependencies:['spinner','numberbox']
},
timespinner:{
js:'jquery.timespinner.js',
dependencies:['spinner']
},
tree:{
js:'jquery.tree.js',
css:'tree.css',
dependencies:['draggable','droppable']
},
datebox:{
js:'jquery.datebox.js',
css:'datebox.css',
dependencies:['calendar','combo']
},
datetimebox:{
js:'jquery.datetimebox.js',
dependencies:['datebox','timespinner']
},
slider:{
js:'jquery.slider.js',
dependencies:['draggable']
},
parser:{
js:'jquery.parser.js'
}
};
var locales = {
'af':'easyui-lang-af.js',
'bg':'easyui-lang-bg.js',
'ca':'easyui-lang-ca.js',
'cs':'easyui-lang-cs.js',
'cz':'easyui-lang-cz.js',
'da':'easyui-lang-da.js',
'de':'easyui-lang-de.js',
'en':'easyui-lang-en.js',
'fr':'easyui-lang-fr.js',
'nl':'easyui-lang-nl.js',
'zh_CN':'easyui-lang-zh_CN.js',
'zh_TW':'easyui-lang-zh_TW.js'
};
var queues = {};
function loadJs(url, callback){
var done = false;
var script = document.createElement('script');
script.type = 'text/javascript';
script.language = 'javascript';
script.src = url;
script.onload = script.onreadystatechange = function(){
if (!done && (!script.readyState || script.readyState == 'loaded' || script.readyState == 'complete')){
done = true;
script.onload = script.onreadystatechange = null;
if (callback){
callback.call(script);
}
}
}
document.getElementsByTagName("head")[0].appendChild(script);
}
function runJs(url, callback){
loadJs(url, function(){
document.getElementsByTagName("head")[0].removeChild(this);
if (callback){
callback();
}
});
}
function loadCss(url, callback){
var link = document.createElement('link');
link.rel = 'stylesheet';
link.type = 'text/css';
link.media = 'screen';
link.href = url;
document.getElementsByTagName('head')[0].appendChild(link);
if (callback){
callback.call(link);
}
}
function loadSingle(name, callback){
queues[name] = 'loading';
var module = modules[name];
var jsStatus = 'loading';
var cssStatus = (easyloader.css && module['css']) ? 'loading' : 'loaded';
if (easyloader.css && module['css']){
if (/^http/i.test(module['css'])){
var url = module['css'];
} else {
var url = easyloader.base + 'themes/' + easyloader.theme + '/' + module['css'];
}
loadCss(url, function(){
cssStatus = 'loaded';
if (jsStatus == 'loaded' && cssStatus == 'loaded'){
finish();
}
});
}
if (/^http/i.test(module['js'])){
var url = module['js'];
} else {
var url = easyloader.base + 'plugins/' + module['js'];
}
loadJs(url, function(){
jsStatus = 'loaded';
if (jsStatus == 'loaded' && cssStatus == 'loaded'){
finish();
}
});
function finish(){
queues[name] = 'loaded';
easyloader.onProgress(name);
if (callback){
callback();
}
}
}
function loadModule(name, callback){
var mm = [];
var doLoad = false;
if (typeof name == 'string'){
add(name);
} else {
for(var i=0; i<name.length; i++){
add(name[i]);
}
}
function add(name){
if (!modules[name]) return;
var d = modules[name]['dependencies'];
if (d){
for(var i=0; i<d.length; i++){
add(d[i]);
}
}
mm.push(name);
}
function finish(){
if (callback){
callback();
}
easyloader.onLoad(name);
}
var time = 0;
function loadMm(){
if (mm.length){
var m = mm[0]; // the first module
if (!queues[m]){
doLoad = true;
loadSingle(m, function(){
mm.shift();
loadMm();
});
} else if (queues[m] == 'loaded'){
mm.shift();
loadMm();
} else {
if (time < easyloader.timeout){
time += 10;
setTimeout(arguments.callee, 10);
}
}
} else {
if (easyloader.locale && doLoad == true && locales[easyloader.locale]){
var url = easyloader.base + 'locale/' + locales[easyloader.locale];
runJs(url, function(){
finish();
});
} else {
finish();
}
}
}
loadMm();
}
easyloader = {
modules:modules,
locales:locales,
base:'.',
theme:'default',
css:true,
locale:null,
timeout:2000,
load: function(name, callback){
if (/\.css$/i.test(name)){
if (/^http/i.test(name)){
loadCss(name, callback);
} else {
loadCss(easyloader.base + name, callback);
}
} else if (/\.js$/i.test(name)){
if (/^http/i.test(name)){
loadJs(name, callback);
} else {
loadJs(easyloader.base + name, callback);
}
} else {
loadModule(name, callback);
}
},
onProgress: function(name){},
onLoad: function(name){}
};
var scripts = document.getElementsByTagName('script');
for(var i=0; i<scripts.length; i++){
var src = scripts[i].src;
if (!src) continue;
var m = src.match(/easyloader\.js(\W|$)/i);
if (m){
easyloader.base = src.substring(0, m.index);
}
}
window.using = easyloader.load;
if (window.jQuery){
jQuery(function(){
easyloader.load('parser', function(){
jQuery.parser.parse();
});
});
}
})();
Dialog的实现
Dialog是最典型的UI组件，使用广泛。
(function($){
/**
* wrap dialog and return content panel.
*/
function wrapDialog(target){
var t = $(target);
t.wrapInner('<div class="dialog-content"></div>');
var contentPanel = t.find('>div.dialog-content');
contentPanel.css('padding', t.css('padding'));
t.css('padding', 0);
contentPanel.panel({
border:false
});
return contentPanel;
}
/**
* build the dialog
*/
function buildDialog(target){
var opts = $.data(target, 'dialog').options;
var contentPanel = $.data(target, 'dialog').contentPanel;
$(target).find('div.dialog-toolbar').remove();
$(target).find('div.dialog-button').remove();
if (opts.toolbar){
var toolbar = $('<div class="dialog-toolbar"></div>').prependTo(target);
for(var i=0; i<opts.toolbar.length; i++){
var p = opts.toolbar[i];
if (p == '-'){
toolbar.append('<div class="dialog-tool-separator"></div>');
} else {
var tool = $('<a href="javascript:void(0)"></a>').appendTo(toolbar);
tool.css('float','left').text(p.text);
if (p.iconCls) tool.attr('icon', p.iconCls);
if (p.handler) tool[0].onclick = p.handler;
tool.linkbutton({
plain: true,
disabled: (p.disabled || false)
});
}
}
toolbar.append('<div style="clear:both"></div>');
}
if (opts.buttons){
var buttons = $('<div class="dialog-button"></div>').appendTo(target);
for(var i=0; i<opts.buttons.length; i++){
var p = opts.buttons[i];
var button = $('<a href="javascript:void(0)"></a>').appendTo(buttons);
if (p.handler) button[0].onclick = p.handler;
button.linkbutton(p);
}
}
if (opts.href){
contentPanel.panel({
href: opts.href,
onLoad: opts.onLoad
});
opts.href = null;
}
$(target).window($.extend({}, opts, {
onResize:function(width, height){
var wbody = $(target).panel('panel').find('>div.panel-body');
contentPanel.panel('resize', {
width: wbody.width(),
height: (height=='auto') ? 'auto' :
wbody.height()
- wbody.find('>div.dialog-toolbar').outerHeight()
- wbody.find('>div.dialog-button').outerHeight()
});
if (opts.onResize) opts.onResize.call(target, width, height);
}
}));
}
function refresh(target){
var contentPanel = $.data(target, 'dialog').contentPanel;
contentPanel.panel('refresh');
}
// 此处定义了一个新的组件：dialog
$.fn.dialog = function(options, param){
if (typeof options == 'string'){
switch(options){
case 'options':
return $(this[0]).window('options');
case 'dialog':
return $(this[0]).window('window');
case 'setTitle':
return this.each(function(){
$(this).window('setTitle', param);
});
case 'open':
return this.each(function(){
$(this).window('open', param);
});
case 'close':
return this.each(function(){
$(this).window('close', param);
});
case 'destroy':
return this.each(function(){
$(this).window('destroy', param);
});
case 'refresh':
return this.each(function(){
refresh(this);
});
case 'resize':
return this.each(function(){
$(this).window('resize', param);
});
case 'move':
return this.each(function(){
$(this).window('move', param);
});
case 'maximize':
return this.each(function(){
$(this).window('maximize');
});
case 'minimize':
return this.each(function(){
$(this).window('minimize');
});
case 'restore':
return this.each(function(){
$(this).window('restore');
});
case 'collapse':
return this.each(function(){
$(this).window('collapse', param);
});
case 'expand':
return this.each(function(){
$(this).window('expand', param);
});
}
}
options = options || {};
// this.each()返回的对象还是this
return this.each(function(){
var state = $.data(this, 'dialog');
if (state){
$.extend(state.options, options);
} else {
var t = $(this);
var opts = $.extend({}, $.fn.dialog.defaults, {
title:(t.attr('title') ? t.attr('title') : undefined),
href:t.attr('href'),
collapsible: (t.attr('collapsible') ? t.attr('collapsible') == 'true' : undefined),
minimizable: (t.attr('minimizable') ? t.attr('minimizable') == 'true' : undefined),
maximizable: (t.attr('maximizable') ? t.attr('maximizable') == 'true' : undefined),
resizable: (t.attr('resizable') ? t.attr('resizable') == 'true' : undefined)
}, options);
$.data(this, 'dialog', {
options: opts,
contentPanel: wrapDialog(this)
});
}
buildDialog(this);
});
};
$.fn.dialog.defaults = {
title: 'New Dialog',
href: null,
collapsible: false,
minimizable: false,
maximizable: false,
resizable: false,
toolbar:null,
buttons:null
};
})(jQuery);
解析如下：
- (function($){})(jQuery) 是常规套路，调用了一个函数，把jQuery对象作为参数传进去。
- $.fn.dialog = function() 定义了一个函数，这个函数返回一个jQuery对象，这个对象是通过执行this.each()方法返回的。在each()里调用buildDialog(this)后，就对这个对象赋予了"生命": 数据和事件处理。所以，当我们执行$(‘#myDialog’).dialog()后，就返回了一个Dialog对象。
其它组件的实现都是和Dialog一个套路。
小结
jQuery easyui的整体架构还是比较清晰的，一个loader加上一堆jQuery插件，每个插件实现一个UI组件。搞清楚了几个关键地方的实现，我们也能自己实现一些简易的UI组件了。
![[附源码]计算机毕业设计影评网站系统Springboot程序](https://img-blog.csdnimg.cn/48bab4f4f45a496583dfb054cf041434.png)
![[附源码]Python计算机毕业设计Django基于Web的软考题库平台](https://img-blog.csdnimg.cn/42e5ca9508a74b429757f6050a8dff4d.png)
