ExtJs源码分析：class Ext.EventManager

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Dec 9, 2008, 3:05:37 AM12/9/08

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原文出处：http://jljlpch.javaeye.com/blog/223726

/**
* author:prk
* date：2008-08-01
* comment:event analyse.
*
*/
/*
* Ext JS Library 2.0
* Copyright(c) 2006-2007, Ext JS, LLC.
* lice...@extjs.com
*
* http://extjs.com/license
*/
/**
* @class Ext.EventManager
* Registers event handlers that want to receive a normalized EventObject instead of the standard browser event and provides
* several useful events directly.
* See {@link Ext.EventObject} for more details on normalized event objects.
* @singleton
*/
Ext.EventManager = function(){
var docReadyEvent, docReadyProcId, docReadyState = false;
var resizeEvent, resizeTask, textEvent, textSize;
var E = Ext.lib.Event;
var D = Ext.lib.Dom;
//docReady的监听函数
var fireDocReady = function(){
if(!docReadyState){
//设定加载完成的标识
docReadyState = true;
Ext.isReady = true;
//对于Safari，成功刚应该clearInterval
if(docReadyProcId){
clearInterval(docReadyProcId);
}
//现在到了remove DOMContentLoaded的事件监听了。
if(Ext.isGecko || Ext.isOpera) {
document.removeEventListener("DOMContentLoaded", fireDocReady, false);
}
//Ie,则remove 生成的元素。
if(Ext.isIE){
var defer = document.getElementById("ie-deferred-loader");
if(defer){
defer.onreadystatechange = null;
defer.parentNode.removeChild(defer);
}
}
//执行docReadyEvent中监听之后除去Listeners
if(docReadyEvent){
docReadyEvent.fire();
docReadyEvent.clearListeners();
}
}
};
//初始化docReady
var initDocReady = function(){
docReadyEvent = new Ext.util.Event();
//对于Opera、Gecko.为document的DOMContentLoaded事件注册fireDocReady监听。
if(Ext.isGecko || Ext.isOpera) {
document.addEventListener("DOMContentLoaded", fireDocReady, false);
}//对于IE，通过强行在document加入一个元素，判断这个元素是否加载完来判断文档是否加载完
//如果加载完了该元素的onreadystatechange的回调函数中的readyState == "complete"
else if(Ext.isIE){
document.write("<s"+'cript id="ie-deferred-loader" defer="defer" src="/'+'/:"></s'+"cript>");
var defer = document.getElementById("ie-deferred-loader");
defer.onreadystatechange = function(){
if(this.readyState == "complete"){
fireDocReady();
}
};
}
//对于Safari，每隔10ms监听它的document.readyState是否==="complete"
else if(Ext.isSafari){
docReadyProcId = setInterval(function(){
var rs = document.readyState;
if(rs == "complete") {
fireDocReady();
}
}, 10);
}
//觉得这里没有必要采用Ext.lib.event.
// no matter what, make sure it fires on load
E.on(window, "load", fireDocReady);
};
//隔多长时间执行一次h函数。
var createBuffered = function(h, o){
var task = new Ext.util.DelayedTask(h);
return function(e){
// create new event object impl so new events don't wipe out properties
e = new Ext.EventObjectImpl(e);
task.delay(o.buffer, h, null, [e]);
};
};
//一个监听执行一次就被remove
var createSingle = function(h, el, ename, fn){
return function(e){
Ext.EventManager.removeListener(el, ename, fn);
h(e);
};
};
//多长时间之后执行h函数
var createDelayed = function(h, o){
return function(e){
// create new event object impl so new events don't wipe out properties
e = new Ext.EventObjectImpl(e);
setTimeout(function(){
h(e);
}, o.delay || 10);
};
};
//为element的ename事件添加fn的监听函数。
var listen = function(element, ename, opt, fn, scope){
var o = (!opt || typeof opt == "boolean") ? {} : opt;
fn = fn || o.fn; scope = scope || o.scope;
var el = Ext.getDom(element);
if(!el){
throw "Error listening for \"" + ename + '\". Element "' + element + '" doesn\'t exist.';
}
//对传进来的fn进行包装
var h = function(e){
e = Ext.EventObject.setEvent(e);
var t;
//找到事件的元素或附近的元素，o.delegate是select
if(o.delegate){
t = e.getTarget(o.delegate, el);
if(!t){
return;
}
}else{
t = e.target;
}
//对元素事件的三种操作，一：stop,二、preventDefault，三、stopPropagation
if(o.stopEvent === true){
e.stopEvent();
}
if(o.preventDefault === true){
e.preventDefault();
}
if(o.stopPropagation === true){
e.stopPropagation();
}
//是否采用原始的浏览事件e,而不是进行了包装的事件。
if(o.normalized === false){
e = e.browserEvent;
}
//fn(event,this,options)
fn.call(scope || el, e, t, o);
};
//推迟执行
if(o.delay){
h = createDelayed(h, o);
}
//监听只执行一次
if(o.single){
h = createSingle(h, el, ename, fn);
}
//隔多少时间就执行一次
if(o.buffer){
h = createBuffered(h, o);
}
fn._handlers = fn._handlers || [];
fn._handlers.push([Ext.id(el), ename, h]);
//为el的ename事件注册h函数。
E.on(el, ename, h);
if(ename == "mousewheel" && el.addEventListener){ // workaround for jQuery
el.addEventListener("DOMMouseScroll", h, false);
E.on(window, 'unload', function(){
el.removeEventListener("DOMMouseScroll", h, false);
});
}
//对document的mousedown,在stopEvent等中要先fire,之后才stop.
if(ename == "mousedown" && el == document){ // fix stopped mousedowns on the document
Ext.EventManager.stoppedMouseDownEvent.addListener(h);
}
return h;
};
var stopListening = function(el, ename, fn){
var id = Ext.id(el), hds = fn._handlers, hd = fn;
if(hds){
for(var i = 0, len = hds.length; i < len; i++){
var h = hds[i];
if(h[0] == id && h[1] == ename){
hd = h[2];
hds.splice(i, 1);
break;
}
}
}
E.un(el, ename, hd);
el = Ext.getDom(el);
if(ename == "mousewheel" && el.addEventListener){
el.removeEventListener("DOMMouseScroll", hd, false);
}
if(ename == "mousedown" && el == document){ // fix stopped mousedowns on the document
Ext.EventManager.stoppedMouseDownEvent.removeListener(hd);
}
};
var propRe = /^(?:scope|delay|buffer|single|stopEvent|preventDefault|stopPropagation|normalized|args|delegate)$/;
var pub = {
/**
* Appends an event handler to an element. The shorthand version {@link #on} is equivalent. Typically you will
* use {@link Ext.Element#addListener} directly on an Element in favor of calling this version.
* @param {String/HTMLElement} el The html element or id to assign the event handler to
* @param {String} eventName The type of event to listen for
* @param {Function} handler The handler function the event invokes
* @param {Object} scope (optional) The scope in which to execute the handler
* function (the handler function's "this" context)
* @param {Object} options (optional) An object containing handler configuration properties.
* This may contain any of the following properties:<ul>
* <li>scope {Object} : The scope in which to execute the handler function. The handler function's "this" context.</li>
* <li>delegate {String} : A simple selector to filter the target or look for a descendant of the target</li>
* <li>stopEvent {Boolean} : True to stop the event. That is stop propagation, and prevent the default action.</li>
* <li>preventDefault {Boolean} : True to prevent the default action</li>
* <li>stopPropagation {Boolean} : True to prevent event propagation</li>
* <li>normalized {Boolean} : False to pass a browser event to the handler function instead of an Ext.EventObject</li>
* <li>delay {Number} : The number of milliseconds to delay the invocation of the handler after te event fires.</li>
* <li>single {Boolean} : True to add a handler to handle just the next firing of the event, and then remove itself.</li>
* <li>buffer {Number} : Causes the handler to be scheduled to run in an {@link Ext.util.DelayedTask} delayed
* by the specified number of milliseconds. If the event fires again within that time, the original
* handler is not invoked, but the new handler is scheduled in its place.</li>
* </ul>
* See {@link Ext.Element#addListener} for examples of how to use these options.
*/
//支持和observable中addListener一样的传参的形式
//这个函数和observable中addListener的结构差不多。不同的把具体的处理放到listen中。
addListener : function(element, eventName, fn, scope, options){
if(typeof eventName == "object"){
var o = eventName;
for(var e in o){
if(propRe.test(e)){
continue;
}
if(typeof o[e] == "function"){
// shared options
listen(element, e, o, o[e], o.scope);
}else{
// individual options
listen(element, e, o[e]);
}
}
return;
}
return listen(element, eventName, options, fn, scope);
},
/**
* Removes an event handler from an element. The shorthand version {@link #un} is equivalent. Typically
* you will use {@link Ext.Element#removeListener} directly on an Element in favor of calling this version.
* @param {String/HTMLElement} el The id or html element from which to remove the event
* @param {String} eventName The type of event
* @param {Function} fn The handler function to remove
* @return {Boolean} True if a listener was actually removed, else false
*/
removeListener : function(element, eventName, fn){
return stopListening(element, eventName, fn);
},
/**
* Fires when the document is ready (before onload and before images are loaded). Can be
* accessed shorthanded as Ext.onReady().
* @param {Function} fn The method the event invokes
* @param {Object} scope (optional) An object that becomes the scope of the handler
* @param {boolean} options (optional) An object containing standard {@link #addListener} options
*/
onDocumentReady : function(fn, scope, options){
//document已经load,为docReadyEvent 进行addListener、fire(),clearListeners();
if(docReadyState){ // if it already fired
docReadyEvent.addListener(fn, scope, options);
docReadyEvent.fire();
docReadyEvent.clearListeners();
return;
}
//初始化Document Ready.
if(!docReadyEvent){
initDocReady();
}
//初始化之后再addListener
docReadyEvent.addListener(fn, scope, options);
},
/**
* Fires when the window is resized and provides resize event buffering (50 milliseconds), passes new viewport width and height to handlers.
* @param {Function} fn The method the event invokes
* @param {Object} scope An object that becomes the scope of the handler
* @param {boolean} options
*/
onWindowResize : function(fn, scope, options){
if(!resizeEvent){
resizeEvent = new Ext.util.Event();
resizeTask = new Ext.util.DelayedTask(function(){
resizeEvent.fire(D.getViewWidth(), D.getViewHeight());
});
E.on(window, "resize", this.fireWindowResize, this);
}
resizeEvent.addListener(fn, scope, options);
},
// exposed only to allow manual firing
fireWindowResize : function(){
if(resizeEvent){
if((Ext.isIE||Ext.isAir) && resizeTask){
resizeTask.delay(50);
}else{
resizeEvent.fire(D.getViewWidth(), D.getViewHeight());
}
}
},
/**
* Fires when the user changes the active text size. Handler gets called with 2 params, the old size and the new size.
* @param {Function} fn The method the event invokes
* @param {Object} scope An object that becomes the scope of the handler
* @param {boolean} options
*/
onTextResize : function(fn, scope, options){
if(!textEvent){
textEvent = new Ext.util.Event();
var textEl = new Ext.Element(document.createElement('div'));
textEl.dom.className = 'x-text-resize';
textEl.dom.innerHTML = 'X';
textEl.appendTo(document.body);
textSize = textEl.dom.offsetHeight;
setInterval(function(){
if(textEl.dom.offsetHeight != textSize){
textEvent.fire(textSize, textSize = textEl.dom.offsetHeight);
}
}, this.textResizeInterval);
}
textEvent.addListener(fn, scope, options);
},
/**
* Removes the passed window resize listener.
* @param {Function} fn The method the event invokes
* @param {Object} scope The scope of handler
*/
removeResizeListener : function(fn, scope){
if(resizeEvent){
resizeEvent.removeListener(fn, scope);
}
},
// private
fireResize : function(){
if(resizeEvent){
resizeEvent.fire(D.getViewWidth(), D.getViewHeight());
}
},
/**
* Url used for onDocumentReady with using SSL (defaults to Ext.SSL_SECURE_URL)
*/
ieDeferSrc : false,
/**
* The frequency, in milliseconds, to check for text resize events (defaults to 50)
*/
textResizeInterval : 50
};
/**
* Appends an event handler to an element. Shorthand for {@link #addListener}.
* @param {String/HTMLElement} el The html element or id to assign the event handler to
* @param {String} eventName The type of event to listen for
* @param {Function} handler The handler function the event invokes
* @param {Object} scope (optional) The scope in which to execute the handler
* function (the handler function's "this" context)
* @param {Object} options (optional) An object containing standard {@link #addListener} options
* @member Ext.EventManager
* @method on
*/
pub.on = pub.addListener;
/**
* Removes an event handler from an element. Shorthand for {@link #removeListener}.
* @param {String/HTMLElement} el The id or html element from which to remove the event
* @param {String} eventName The type of event
* @param {Function} fn The handler function to remove
* @return {Boolean} True if a listener was actually removed, else false
* @member Ext.EventManager
* @method un
*/
pub.un = pub.removeListener;
pub.stoppedMouseDownEvent = new Ext.util.Event();
return pub;
}();
/**
* Fires when the document is ready (before onload and before images are loaded). Shorthand of {@link Ext.EventManager#onDocumentReady}.
* @param {Function} fn The method the event invokes
* @param {Object} scope An object that becomes the scope of the handler
* @param {boolean} override If true, the obj passed in becomes
* the execution scope of the listener
* @member Ext
* @method onReady
*/
Ext.onReady = Ext.EventManager.onDocumentReady;
Ext.onReady(function(){
var bd = Ext.getBody();
if(!bd){ return; }
var cls = [
Ext.isIE ? "ext-ie " + (Ext.isIE6 ? 'ext-ie6' : 'ext-ie7')
: Ext.isGecko ? "ext-gecko"
: Ext.isOpera ? "ext-opera"
: Ext.isSafari ? "ext-safari" : ""];
if(Ext.isMac){
cls.push("ext-mac");
}
if(Ext.isLinux){
cls.push("ext-linux");
}
if(Ext.isBorderBox){
cls.push('ext-border-box');
}
if(Ext.isStrict){ // add to the parent to allow for selectors like ".ext-strict .ext-ie"
var p = bd.dom.parentNode;
if(p){
p.className += ' ext-strict';
}
}
bd.addClass(cls.join(' '));
});
/**
* @class Ext.EventObject
* EventObject exposes the Yahoo! UI Event functionality directly on the object
* passed to your event handler. It exists mostly for convenience. It also fixes the annoying null checks automatically to cleanup your code
* Example:
* <pre><code>
function handleClick(e){ // e is not a standard event object, it is a Ext.EventObject
e.preventDefault();
var target = e.getTarget();
...
}
var myDiv = Ext.get("myDiv");
myDiv.on("click", handleClick);
//or
Ext.EventManager.on("myDiv", 'click', handleClick);
Ext.EventManager.addListener("myDiv", 'click', handleClick);
</code></pre>
* @singleton
*/
Ext.EventObject = function(){
var E = Ext.lib.Event;
// safari keypress events for special keys return bad keycodes
var safariKeys = {
63234 : 37, // left
63235 : 39, // right
63232 : 38, // up
63233 : 40, // down
63276 : 33, // page up
63277 : 34, // page down
63272 : 46, // delete
63273 : 36, // home
63275 : 35 // end
};
// normalize button clicks
//表示鼠标的左，中，右键，每种浏览器不一同，统一为0,1,2.
var btnMap = Ext.isIE ? {1:0,4:1,2:2} :
(Ext.isSafari ? {1:0,2:1,3:2} : {0:0,1:1,2:2});
Ext.EventObjectImpl = function(e){
if(e){
this.setEvent(e.browserEvent || e);
}
};
Ext.EventObjectImpl.prototype = {
/** The normal browser event */
browserEvent : null,
/** The button pressed in a mouse event */
button : -1,
/** True if the shift key was down during the event */
shiftKey : false,
/** True if the control key was down during the event */
ctrlKey : false,
/** True if the alt key was down during the event */
altKey : false,
//一些常用的按键。
/** Key constant @type Number */
BACKSPACE : 8,
/** Key constant @type Number */
TAB : 9,
/** Key constant @type Number */
RETURN : 13,
/** Key constant @type Number */
ENTER : 13,
/** Key constant @type Number */
SHIFT : 16,
/** Key constant @type Number */
CONTROL : 17,
/** Key constant @type Number */
ESC : 27,
/** Key constant @type Number */
SPACE : 32,
/** Key constant @type Number */
PAGEUP : 33,
/** Key constant @type Number */
PAGEDOWN : 34,
/** Key constant @type Number */
END : 35,
/** Key constant @type Number */
HOME : 36,
/** Key constant @type Number */
LEFT : 37,
/** Key constant @type Number */
UP : 38,
/** Key constant @type Number */
RIGHT : 39,
/** Key constant @type Number */
DOWN : 40,
/** Key constant @type Number */
DELETE : 46,
/** Key constant @type Number */
F5 : 116,
/** @private */
//包装事件。
setEvent : function(e){
if(e == this || (e && e.browserEvent)){ // already wrapped
return e;
}
//设定 this.browserEvent=传入的浏览器的event,做为是否包装的标识。
this.browserEvent = e;
if(e){
// normalize buttons，比prototype实现简单多了。表示鼠标按键。
this.button = e.button ? btnMap[e.button] : (e.which ? e.which-1 : -1);
if(e.type == 'click' && this.button == -1){
this.button = 0;
}
//事件名
this.type = e.type;
//三个功能组合键
this.shiftKey = e.shiftKey;
// mac metaKey behaves like ctrlKey
this.ctrlKey = e.ctrlKey || e.metaKey;
this.altKey = e.altKey;
//键盘事件的keywode,and charcode
// in getKey these will be normalized for the mac
this.keyCode = e.keyCode;
this.charCode = e.charCode;
//我倒是觉得这里的不好，不应该采用 Ext.lib.Event，组合在一起很方便啊
//可能是出于版本兼容等问题的考虑吧。
// cache the target for the delayed and or buffered events
this.target = E.getTarget(e);
// same for XY
this.xy = E.getXY(e);
}else{
this.button = -1;
this.shiftKey = false;
this.ctrlKey = false;
this.altKey = false;
this.keyCode = 0;
this.charCode =0;
this.target = null;
this.xy = [0, 0];
}
return this;
},
/**
* Stop the event (preventDefault and stopPropagation)
*/
//觉得stopEvent，preventDefault,stopPropagation完全可以独立实现。
stopEvent : function(){
if(this.browserEvent){
if(this.browserEvent.type == 'mousedown'){
Ext.EventManager.stoppedMouseDownEvent.fire(this);
}
E.stopEvent(this.browserEvent);
}
},
/**
* Prevents the browsers default handling of the event.
*/
// this.browserEven.returnValue = false;
preventDefault : function(){
if(this.browserEvent){
E.preventDefault(this.browserEvent);
}
},
/** @private */
//判断键是不是字符按键，除去了一些功能键
isNavKeyPress : function(){
var k = this.keyCode;
k = Ext.isSafari ? (safariKeys[k] || k) : k;
return (k >= 33 && k <= 40) || k == this.RETURN || k == this.TAB || k == this.ESC;
},
//判断是不是特殊键。
isSpecialKey : function(){
var k = this.keyCode;
return (this.type == 'keypress' && this.ctrlKey) || k == 9 || k == 13 || k == 40 || k == 27 ||
(k == 16) || (k == 17) ||
(k >= 18 && k <= 20) ||
(k >= 33 && k <= 35) ||
(k >= 36 && k <= 39) ||
(k >= 44 && k <= 45);
},
/**
* Cancels bubbling of the event.
*/
//this.browserEvent.cancelBubble=false
stopPropagation : function(){
if(this.browserEvent){
if(this.browserEvent.type == 'mousedown'){
Ext.EventManager.stoppedMouseDownEvent.fire(this);
}
E.stopPropagation(this.browserEvent);
}
},
//取得键值和其代码
/**
* Gets the key code for the event.
* @return {Number}
*/
getCharCode : function(){
return this.charCode || this.keyCode;
},
/**
* Returns a normalized keyCode for the event.
* @return {Number} The key code
*/
getKey : function(){
var k = this.keyCode || this.charCode;
return Ext.isSafari ? (safariKeys[k] || k) : k;
},
//取得事件页面的位置
/**
* Gets the x coordinate of the event.
* @return {Number}
*/
getPageX : function(){
return this.xy[0];
},
/**
* Gets the y coordinate of the event.
* @return {Number}
*/
getPageY : function(){
return this.xy[1];
},
/**
* Gets the time of the event.
* @return {Number}
*/
getTime : function(){
if(this.browserEvent){
return E.getTime(this.browserEvent);
}
return null;
},
/**
* Gets the page coordinates of the event.
* @return {Array} The xy values like [x, y]
*/
getXY : function(){
return this.xy;
},
/**
* Gets the target for the event.
* @param {String} selector (optional) A simple selector to filter the target or look for an ancestor of the target
* @param {Number/Mixed} maxDepth (optional) The max depth to
search as a number or element (defaults to 10 || document.body)
* @param {Boolean} returnEl (optional) True to return a Ext.Element object instead of DOM node
* @return {HTMLelement}
*/
//和prototype中findElement差不多，找到事件源元素附近的元素。
getTarget : function(selector, maxDepth, returnEl){
var t = Ext.get(this.target);
return selector ? t.findParent(selector, maxDepth, returnEl) : (returnEl ? t : this.target);
},
/**
* Gets the related target.
* @return {HTMLElement}
*/
getRelatedTarget : function(){
if(this.browserEvent){
return E.getRelatedTarget(this.browserEvent);
}
return null;
},
/**
* Normalizes mouse wheel delta across browsers
* @return {Number} The delta
*/
getWheelDelta : function(){
var e = this.browserEvent;
var delta = 0;
if(e.wheelDelta){ /* IE/Opera. */
delta = e.wheelDelta/120;
}else if(e.detail){ /* Mozilla case. */
delta = -e.detail/3;
}
return delta;
},
/**
* Returns true if the control, meta, shift or alt key was pressed during this event.
* @return {Boolean}
*/
hasModifier : function(){
return ((this.ctrlKey || this.altKey) || this.shiftKey) ? true : false;
},
/**
* Returns true if the target of this event equals el or is a child of el
* @param {Mixed} el
* @param {Boolean} related (optional) true to test if the related target is within el instead of the target
* @return {Boolean}
*/
within : function(el, related){
var t = this[related ? "getRelatedTarget" : "getTarget"]();
return t && Ext.fly(el).contains(t);
},
getPoint : function(){
return new Ext.lib.Point(this.xy[0], this.xy[1]);
}
};
return new Ext.EventObjectImpl();
}();

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