Use SplitWindow w/ Titanium and toggle MasterView based on both orientation + if in SplitView/SplitOver Mode

ti_splitwindow.js

//XML
<Alloy>
	<SplitWindow id="splitWindow" backgroundColor="white" showMasterInPortrait="true" masterIsOverlayed="true" platform="ios">
		<!--MASTER-->
		<NavigationWindow platform="ios">
			<Window title="Master" layout="vertical">
				<LeftNavButtons>
					<Label id="masterCollapseButton" class="navButton" text="<<" onClick="toggleMaster" />
				</LeftNavButtons>
					
				<Label text="Master View" />
			</Window>
		</NavigationWindow>

		<!--DETAIL-->
		<NavigationWindow platform="ios" id="detailNavWindow">
			<Window title="Detail" id="detailWindow" class="container" layout="vertical" backgroundColor="#cccccc">
				<LeftNavButtons>
					<Label id="masterOpenButton" class="navButton" text=">>" onClick="toggleMaster" />
				</LeftNavButtons>

				<Label text="Detail View" />
			</Window>
		</NavigationWindow>

	</SplitWindow>
</Alloy>


//JS
var showMaster = true;
Alloy.Globals.deviceSmallestMeasurement = (parseInt(Ti.Platform.displayCaps.platformWidth) < parseInt(Ti.Platform.displayCaps.platformHeight)) ? parseInt(Ti.Platform.displayCaps.platformWidth) : parseInt(Ti.Platform.displayCaps.platformHeight);

function toggleMaster(){
	$.splitWindow.masterViewVisible = !showMaster;
	showMaster = !showMaster;
}

/**
* Executes when rotated, resumed, or even when introduced to SplitView or SplitOver Mode
*/
$.splitWindow.addEventListener('postlayout',function(e) {	
		if ($.splitWindow.toImage().width <= Alloy.Globals.deviceSmallestMeasurement) {
			//act as Portrait
			$.masterCollapseButton.visible = true;
			$.masterOpenButton.visible = true;
		} else {
			//landscape
			$.masterCollapseButton.visible = false;
			$.masterOpenButton.visible = false;
			if (!$.splitWindow.masterViewVisible) { toggleMaster(); }	//when rotating to landscape, if master is hidden toggle it to be visible
		}
});