dojo_app/js/library/dojox/mobile/_ScrollableMixin.js

define([
	"dojo/_base/kernel",
	"dojo/_base/config",
	"dojo/_base/declare",
	"dojo/_base/lang",
	"dojo/_base/window",
	"dojo/dom",
	"dojo/dom-class",
	"dijit/registry",	// registry.byNode
	"./scrollable"
], function(dojo, config, declare, lang, win, dom, domClass, registry, Scrollable){
	// module:
	//		dojox/mobile/_ScrollableMixin

	var cls = declare("dojox.mobile._ScrollableMixin", Scrollable, {
		// summary:
		//		Mixin for widgets to have a touch scrolling capability.
	
		// fixedHeader: String
		//		Id of the fixed header.
		fixedHeader: "",

		// fixedFooter: String
		//		Id of the fixed footer.
		fixedFooter: "",

		_fixedAppFooter: "",

		// scrollableParams: Object
		//		Parameters for dojox/mobile/scrollable.init().
		scrollableParams: null,

		// allowNestedScrolls: Boolean
		//		Flag to allow scrolling in nested containers, e.g. to allow ScrollableView in a SwapView.
		allowNestedScrolls: true,

		// appBars: Boolean
		//		Enables the search for application-specific bars (header or footer).
		appBars: true, 

		constructor: function(){
			// summary:
			//		Creates a new instance of the class.
			// tags:
			//		private
			this.scrollableParams = {};
		},

		destroy: function(){
			this.cleanup();
			this.inherited(arguments);
		},

		startup: function(){
			if(this._started){ return; }
			if(this._fixedAppFooter){
				this._fixedAppFooter = dom.byId(this._fixedAppFooter);
			}
			this.findAppBars();
			var node, params = this.scrollableParams;
			if(this.fixedHeader){
				node = dom.byId(this.fixedHeader);
				if(node.parentNode == this.domNode){ // local footer
					this.isLocalHeader = true;
				}
				params.fixedHeaderHeight = node.offsetHeight;
			}
			if(this.fixedFooter){
				node = dom.byId(this.fixedFooter);
				if(node.parentNode == this.domNode){ // local footer
					this.isLocalFooter = true;
					node.style.bottom = "0px";
				}
				params.fixedFooterHeight = node.offsetHeight;
			}
			this.scrollType = this.scrollType || config.mblScrollableScrollType || 0;
			this.init(params);
			if(this.allowNestedScrolls){
				for(var p = this.getParent(); p; p = p.getParent()){
					if(p && p.scrollableParams){
						this.dirLock = true;
						p.dirLock = true;
						break;
					}
				}
			}
			// subscribe to afterResizeAll to scroll the focused input field into view
			// so as not to break layout on orientation changes while keyboard is shown (#14991)
			this._resizeHandle = this.subscribe("/dojox/mobile/afterResizeAll", function(){
				if(this.domNode.style.display === 'none'){ return; }
				var elem = win.doc.activeElement;
				if(this.isFormElement(elem) && dom.isDescendant(elem, this.containerNode)){
					this.scrollIntoView(elem);
				}
			});
			this.inherited(arguments);
		},

		findAppBars: function(){
			// summary:
			//		Search for application-specific header or footer.
			if(!this.appBars){ return; }
			var i, len, c;
			for(i = 0, len = win.body().childNodes.length; i < len; i++){
				c = win.body().childNodes[i];
				this.checkFixedBar(c, false);
			}
			if(this.domNode.parentNode){
				for(i = 0, len = this.domNode.parentNode.childNodes.length; i < len; i++){
					c = this.domNode.parentNode.childNodes[i];
					this.checkFixedBar(c, false);
				}
			}
			this.fixedFooterHeight = this.fixedFooter ? this.fixedFooter.offsetHeight : 0;
		},

		checkFixedBar: function(/*DomNode*/node, /*Boolean*/local){
			// summary:
			//		Checks if the given node is a fixed bar or not.
			if(node.nodeType === 1){
				var fixed = node.getAttribute("fixed") // TODO: Remove the non-HTML5-compliant attribute in 2.0
					|| node.getAttribute("data-mobile-fixed")
					|| (registry.byNode(node) && registry.byNode(node).fixed);
				if(fixed === "top"){
					domClass.add(node, "mblFixedHeaderBar");
					if(local){
						node.style.top = "0px";
						this.fixedHeader = node;
					}
					return fixed;
				}else if(fixed === "bottom"){
					domClass.add(node, "mblFixedBottomBar");
					if(local){
						this.fixedFooter = node;
					}else{
						this._fixedAppFooter = node;
					}
					return fixed;
				}
			}
			return null;
		}
	});
	return cls;
});