API: uploader FlashAdapter.js (YUI Library)

# Yahoo! UI Library

### Uploader 2.8.1

Yahoo! UI Library > uploader > FlashAdapter.js (source view)
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    /**
     * Wraps Flash embedding functionality and allows communication with SWF through
     * attributes.
     *
     * @namespace YAHOO.widget
     * @class FlashAdapter
     * @uses YAHOO.util.AttributeProvider
     */
    YAHOO.widget.FlashAdapter = function(swfURL, containerID, attributes, buttonSkin)
    {

    	this._queue = this._queue || [];
    	this._events = this._events || {};
    	this._configs = this._configs || {};
    	attributes = attributes || {};

    	//the Flash Player external interface code from Adobe doesn't play nicely
    	//with the default value, yui-gen, in IE
    	this._id = attributes.id = attributes.id || YAHOO.util.Dom.generateId(null, "yuigen");
    	attributes.version = attributes.version || "9.0.45";
    	attributes.backgroundColor = attributes.backgroundColor || "#ffffff";

    	//we can't use the initial attributes right away
    	//so save them for once the SWF finishes loading
    	this._attributes = attributes;

    	this._swfURL = swfURL;
    	this._containerID = containerID;

    	//embed the SWF file in the page
    	this._embedSWF(this._swfURL, this._containerID, attributes.id, attributes.version,
    		attributes.backgroundColor, attributes.expressInstall, attributes.wmode, buttonSkin);

    	/**
    	 * Fires when the SWF is initialized and communication is possible.
    	 * @event contentReady
    	 */
    	//Fix for iframe cross-domain issue with FF2x
    	try
    	{
    		this.createEvent("contentReady");
    	}
    	catch(e){}
    };

    YAHOO.widget.FlashAdapter.owners = YAHOO.widget.FlashAdapter.owners || {};

    YAHOO.extend(YAHOO.widget.FlashAdapter, YAHOO.util.AttributeProvider,
    {
    	/**
    	 * The URL of the SWF file.
    	 * @property _swfURL
    	 * @type String
    	 * @private
    	 */
    	_swfURL: null,

    	/**
    	 * The ID of the containing DIV.
    	 * @property _containerID
    	 * @type String
    	 * @private
    	 */
    	_containerID: null,

    	/**
    	 * A reference to the embedded SWF file.
    	 * @property _swf
    	 * @private
    	 */
    	_swf: null,

    	/**
    	 * The id of this instance.
    	 * @property _id
    	 * @type String
    	 * @private
    	 */
    	_id: null,

    	/**
    	 * Indicates whether the SWF has been initialized and is ready
    	 * to communicate with JavaScript
    	 * @property _initialized
    	 * @type Boolean
    	 * @private
    	 */
    	_initialized: false,

    	/**
    	 * The initializing attributes are stored here until the SWF is ready.
    	 * @property _attributes
    	 * @type Object
    	 * @private
    	 */
    	_attributes: null, //the intializing attributes

    	/**
    	 * Public accessor to the unique name of the FlashAdapter instance.
    	 *
    	 * @method toString
    	 * @return {String} Unique name of the FlashAdapter instance.
    	 */
    	toString: function()
    	{
    		return "FlashAdapter " + this._id;
    	},

    	/**
    	 * Nulls out the entire FlashAdapter instance and related objects and removes attached
    	 * event listeners and clears out DOM elements inside the container. After calling
    	 * this method, the instance reference should be expliclitly nulled by implementer,
    	 * as in myChart = null. Use with caution!
    	 *
    	 * @method destroy
    	 */
    	destroy: function()
    	{
    		//kill the Flash Player instance
    		if(this._swf)
    		{
    			var container = YAHOO.util.Dom.get(this._containerID);
    			container.removeChild(this._swf);
    		}

    		var instanceName = this._id;

    		//null out properties
    		for(var prop in this)
    		{
    			if(YAHOO.lang.hasOwnProperty(this, prop))
    			{
    				this[prop] = null;
    			}
    		}

    		YAHOO.log("FlashAdapter instance destroyed: " + instanceName);
    	},

    	/**
    	 * Embeds the SWF in the page and associates it with this instance.
    	 *
    	 * @method _embedSWF
    	 * @private
    	 */
    	_embedSWF: function(swfURL, containerID, swfID, version, backgroundColor, expressInstall, wmode, buttonSkin)
    	{
    		//standard SWFObject embed
    		var swfObj = new YAHOO.deconcept.SWFObject(swfURL, swfID, "100%", "100%", version, backgroundColor);

    		if(expressInstall)
    		{
    			swfObj.useExpressInstall(expressInstall);
    		}

    		//make sure we can communicate with ExternalInterface
    		swfObj.addParam("allowScriptAccess", "always");

    		if(wmode)
    		{
    			swfObj.addParam("wmode", wmode);
    		}

    		swfObj.addParam("menu", "false");

    		//again, a useful ExternalInterface trick
    		swfObj.addVariable("allowedDomain", document.location.hostname);

    		//tell the SWF which HTML element it is in
    		swfObj.addVariable("YUISwfId", swfID);

    		// set the name of the function to call when the swf has an event
    		swfObj.addVariable("YUIBridgeCallback", "YAHOO.widget.FlashAdapter.eventHandler");
    		if (buttonSkin) {
    		swfObj.addVariable("buttonSkin", buttonSkin);
    		}
    		var container = YAHOO.util.Dom.get(containerID);
    		var result = swfObj.write(container);
    		if(result)
    		{
    			this._swf = YAHOO.util.Dom.get(swfID);
    			YAHOO.widget.FlashAdapter.owners[swfID] = this;
    		}
    		else
    		{
    			YAHOO.log("Unable to load SWF " + swfURL);
    		}
    	},

    	/**
    	 * Handles or re-dispatches events received from the SWF.
    	 *
    	 * @method _eventHandler
    	 * @private
    	 */
    	_eventHandler: function(event)
    	{
    		var type = event.type;
    		switch(type)
    		{
    			case "swfReady":
       				this._loadHandler();
    				return;
    			case "log":
    				YAHOO.log(event.message, event.category, this.toString());
    				return;
    		}

    		//be sure to return after your case or the event will automatically fire!
    		this.fireEvent(type, event);
    	},

    	/**
    	 * Called when the SWF has been initialized.
    	 *
    	 * @method _loadHandler
    	 * @private
    	 */
    	_loadHandler: function()
    	{
    		this._initialized = false;
    		this._initAttributes(this._attributes);
    		this.setAttributes(this._attributes, true);

    		this._initialized = true;
    		this.fireEvent("contentReady");
    	},

    	set: function(name, value)
    	{
    		//save all the attributes in case the swf reloads
    		//so that we can pass them in again
    		this._attributes[name] = value;
    		YAHOO.widget.FlashAdapter.superclass.set.call(this, name, value);
    	},

    	/**
    	 * Initializes the attributes.
    	 *
    	 * @method _initAttributes
    	 * @private
    	 */
    	_initAttributes: function(attributes)
    	{
    		//should be overridden if other attributes need to be set up

    		/**
    		 * @attribute wmode
    		 * @description Sets the window mode of the Flash Player control. May be
    		 *		"window", "opaque", or "transparent". Only available in the constructor
    		 *		because it may not be set after Flash Player has been embedded in the page.
    		 * @type String
    		 */

    		/**
    		 * @attribute expressInstall
    		 * @description URL pointing to a SWF file that handles Flash Player's express
    		 *		install feature. Only available in the constructor because it may not be
    		 *		set after Flash Player has been embedded in the page.
    		 * @type String
    		 */

    		/**
    		 * @attribute version
    		 * @description Minimum required version for the SWF file. Only available in the constructor because it may not be
    		 *		set after Flash Player has been embedded in the page.
    		 * @type String
    		 */

    		/**
    		 * @attribute backgroundColor
    		 * @description The background color of the SWF. Only available in the constructor because it may not be
    		 *		set after Flash Player has been embedded in the page.
    		 * @type String
    		 */

    		/**
    		 * @attribute altText
    		 * @description The alternative text to provide for screen readers and other assistive technology.
    		 * @type String
    		 */
    		this.getAttributeConfig("altText",
    		{
    			method: this._getAltText
    		});
    		this.setAttributeConfig("altText",
    		{
    			method: this._setAltText
    		});

    		/**
    		 * @attribute swfURL
    		 * @description Absolute or relative URL to the SWF displayed by the FlashAdapter. Only available in the constructor because it may not be
    		 *		set after Flash Player has been embedded in the page.
    		 * @type String
    		 */
    		this.getAttributeConfig("swfURL",
    		{
    			method: this._getSWFURL
    		});
    	},

    	/**
    	 * Getter for swfURL attribute.
    	 *
    	 * @method _getSWFURL
    	 * @private
    	 */
    	_getSWFURL: function()
    	{
    		return this._swfURL;
    	},

    	/**
    	 * Getter for altText attribute.
    	 *
    	 * @method _getAltText
    	 * @private
    	 */
    	_getAltText: function()
    	{
    		return this._swf.getAltText();
    	},

    	/**
    	 * Setter for altText attribute.
    	 *
    	 * @method _setAltText
    	 * @private
    	 */
    	_setAltText: function(value)
    	{
    		return this._swf.setAltText(value);
    	}
    });

    /**
     * Receives event messages from SWF and passes them to the correct instance
     * of FlashAdapter.
     *
     * @method YAHOO.widget.FlashAdapter.eventHandler
     * @static
     * @private
     */
    YAHOO.widget.FlashAdapter.eventHandler = function(elementID, event)
    {

    	if(!YAHOO.widget.FlashAdapter.owners[elementID])
    	{
    		//fix for ie: if owner doesn't exist yet, try again in a moment
    		setTimeout(function() { YAHOO.widget.FlashAdapter.eventHandler( elementID, event ); }, 0);
    	}
    	else
    	{
    		YAHOO.widget.FlashAdapter.owners[elementID]._eventHandler(event);
    	}
    };

    /**
     * The number of proxy functions that have been created.
     * @static
     * @private
     */
    YAHOO.widget.FlashAdapter.proxyFunctionCount = 0;

    /**
     * Creates a globally accessible function that wraps a function reference.
     * Returns the proxy function's name as a string for use by the SWF through
     * ExternalInterface.
     *
     * @method YAHOO.widget.FlashAdapter.createProxyFunction
     * @static
     * @private
     */
    YAHOO.widget.FlashAdapter.createProxyFunction = function(func)
    {
    	var index = YAHOO.widget.FlashAdapter.proxyFunctionCount;
    	YAHOO.widget.FlashAdapter["proxyFunction" + index] = function()
    	{
    		return func.apply(null, arguments);
    	};
    	YAHOO.widget.FlashAdapter.proxyFunctionCount++;
    	return "YAHOO.widget.FlashAdapter.proxyFunction" + index.toString();
    };

    /**
     * Removes a function created with createProxyFunction()
     *
     * @method YAHOO.widget.FlashAdapter.removeProxyFunction
     * @static
     * @private
     */
    YAHOO.widget.FlashAdapter.removeProxyFunction = function(funcName)
    {
    	//quick error check
    	if(!funcName || funcName.indexOf("YAHOO.widget.FlashAdapter.proxyFunction") < 0)
    	{
    		return;
    	}

    	funcName = funcName.substr(26);
    	YAHOO.widget.FlashAdapter[funcName] = null;
    };

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