Resolved Issue #391: Added cancellable Android activityBackPressed event + fixed the names of the other activity events because they were wrong.

application/application.android.ts

@@ -11,14 +11,15 @@ var callbacks = android.app.Application.ActivityLifecycleCallbacks;
 
 export var mainModule: string;
 
-export var androidActivityCreatedEvent = "androidActivityCreated";
-export var androidActivityDestroyedEvent = "androidActivityDestroyed";
-export var androidActivityStartedEvent = "androidActivityStarted";
-export var androidActivityPausedEvent = "androidActivityPaused";
-export var androidActivityResumedEvent = "androidActivityResumed";
-export var androidActivityStoppedEvent = "androidActivityStopped";
-export var androidSaveActivityStateEvent = "androidSaveActivityState";
-export var androidActivityResultEvent = "androidActivityResult";
+export var androidActivityCreatedEvent = "activityCreated";
+export var androidActivityDestroyedEvent = "activityDestroyed";
+export var androidActivityStartedEvent = "activityStarted";
+export var androidActivityPausedEvent = "activityPaused";
+export var androidActivityResumedEvent = "activityResumed";
+export var androidActivityStoppedEvent = "activityStopped";
+export var androidSaveActivityStateEvent = "saveActivityState";
+export var androidActivityResultEvent = "activityResult";
+export var androidActivityBackPressedEvent = "activityBackPressed";
 
 // We are using the exports object for the common events since we merge the appModule with this module's exports, which is what users will receive when require("application") is called;
 // TODO: This is kind of hacky and is "pure JS in TypeScript"
@@ -163,7 +164,6 @@ class AndroidApplication implements dts.AndroidApplication {
     public onActivityResumed: (activity: android.app.Activity) => void;
     public onActivityStopped: (activity: android.app.Activity) => void;
     public onSaveActivityState: (activity: android.app.Activity, bundle: android.os.Bundle) => void;
-
     public onActivityResult: (requestCode: number, resultCode: number, data: android.content.Intent) => void;
 
     private _eventsToken: any;

application/application.d.ts

@@ -250,6 +250,16 @@ declare module "application" {
         intent: android.content.Intent;
     }
 
+    /**
+     * Data for the Android activity back pressed event.
+     */
+    export interface AndroidActivityBackPressedEventData extends AndroidActivityEventData {
+        /**
+         * In the event handler, set this value to true if you want to cancel the back navigation and do something else instead.
+         */
+        cancel: boolean;
+    }
+
     /**
      * This event is raised on android application ActivityCreated.
      */
@@ -290,6 +300,11 @@ declare module "application" {
      */
     export function on(event: "activityResult", callback: (args: AndroidActivityResultEventData) => void, thisArg?: any);
 
+    /**
+     * This event is raised on the back button is pressed in an android application.
+     */
+    export function on(event: "activityBackPressed", callback: (args: AndroidActivityBackPressedEventData) => void, thisArg?: any);
+
     /**
      * String value used when hooking to ActivityCreated event.
      */
@@ -330,6 +345,11 @@ declare module "application" {
      */
     export var androidActivityResultEvent: string;
 
+    /**
+     * String value used when hooking to ActivityBackPressed event.
+     */
+    export var androidActivityBackPressedEvent: string;
+
     /**
      * The abstraction of an Android-specific application object.
      */

apps/tests/app/app.ts

@@ -98,6 +98,10 @@ if (platform.device.os === platform.platformNames.android) {
     application.on(application.androidSaveActivityStateEvent, function (args: application.AndroidActivityBundleEventData) {
         console.log("Event: " + args.eventName + ", Activity: " + args.activity + ", Bundle: " + args.bundle);
     });
+
+    application.on(application.androidActivityBackPressedEvent, function (args: application.AndroidActivityBackPressedEventData) {
+        console.log("Event: " + args.eventName + ", Activity: " + args.activity);
+    });
 }
 
 application.start();

ui/frame/frame.android.ts

@@ -494,6 +494,19 @@ var NativeActivity = {
 
     onBackPressed: function () {
         trace.write("NativeScriptActivity.onBackPressed;", trace.categories.NativeLifecycle);
+
+        var args = <application.AndroidActivityBackPressedEventData>{
+            eventName: application.androidActivityBackPressedEvent,
+            object: application.android,
+            activity: this,
+            cancel: false,
+        };
+        application.notify(args);
+
+        if (args.cancel) {
+            return;
+        }
+
         if (!frameCommon.goBack()) {
             this.super.onBackPressed();
         }