import { android as androidApp, AndroidActivityBackPressedEventData } from "tns-core-modules/application"; import { fromObject, Observable } from "tns-core-modules/data/observable" let context: Observable; function activityBackPressedCallback(args: AndroidActivityBackPressedEventData) { if (context && context.get("shouldCancel")) { context.set("shouldCancel", false); context.set("message", "Back-pressed canceled!"); args.cancel = true; } } export function onLoaded(args) { console.log("back-button modal test loaded"); context = fromObject({ message: "First back-press will be canceled", shouldCancel: true }); args.object.bindingContext = context; if (androidApp) { androidApp.on("activityBackPressed", activityBackPressedCallback); } } export function onUnloaded(args) { console.log("back-button modal test unloaded"); if (androidApp) { androidApp.off("activityBackPressed", activityBackPressedCallback); } }