import application = require("application"); import observable = require("data/observable"); import pageModule = require("ui/page"); var vm = new observable.Observable(); function orientationChanged(data) { console.log("Orientation changed: " + data.newValue); vm.set("orientation", data.newValue); } export function onPageLoaded(args: observable.EventData) { var page = args.object; application.on(application.orientationChangedEvent, orientationChanged, page); page.bindingContext = vm; vm.set("orientation", "not changed"); } export function onPageUnloaded(args: observable.EventData) { var page = args.object; application.off(application.orientationChangedEvent, orientationChanged, page); }