fix: engagement time in first screen view when app warm starts

clickstream/src/main/java/software/aws/solution/clickstream/ActivityLifecycleManager.java

@@ -37,6 +37,7 @@
  **/
 final class ActivityLifecycleManager implements Application.ActivityLifecycleCallbacks, LifecycleEventObserver {
     private static final Log LOG = LogFactory.getLog(ActivityLifecycleManager.class);
+    private static boolean isFromForeground;
     private final SessionClient sessionClient;
     private final AutoRecordEventClient autoRecordEventClient;
 
@@ -84,9 +85,14 @@ public void onActivityResumed(final Activity activity) {
             ScreenRefererTool.isSameScreen(activity.getClass().getCanonicalName(), activity.getClass().getSimpleName(),
                 autoRecordEventClient.getScreenUniqueId(activity));
         if (ScreenRefererTool.getCurrentScreenName() != null && !isSameScreen) {
-            autoRecordEventClient.recordUserEngagement();
+            if (!isFromForeground) {
+                autoRecordEventClient.recordUserEngagement();
+            } else {
+                autoRecordEventClient.resetLastEngageTime();
+            }
         }
         autoRecordEventClient.recordViewScreen(activity);
+        isFromForeground = false;
     }
 
     @Override
@@ -127,6 +133,7 @@ public void onStateChanged(@NonNull LifecycleOwner lifecycleOwner, @NonNull Life
             autoRecordEventClient.flushEvents();
         } else if (event == Lifecycle.Event.ON_START) {
             LOG.debug("Application entered the foreground.");
+            isFromForeground = true;
             autoRecordEventClient.handleAppStart();
             boolean isNewSession = sessionClient.initialSession();
             if (isNewSession) {

clickstream/src/main/java/software/aws/solution/clickstream/client/AutoRecordEventClient.java

@@ -157,6 +157,13 @@ public void updateStartEngageTimestamp() {
         startEngageTimestamp = System.currentTimeMillis();
     }
 
+    /**
+     * reset last engagement time when app warm start.
+     */
+    public void resetLastEngageTime() {
+        lastEngageTime = 0;
+    }
+
     /**
      * check and record _app_update event.
      */

clickstream/src/test/java/software/aws/solution/clickstream/AutoRecordEventClientTest.java

@@ -450,6 +450,41 @@ public void testPreviousTimestampInTwoScreenViewEvent() throws Exception {
         }
     }
 
+    /**
+     * test app warm start without engagement_mesc attribute.
+     *
+     * @throws Exception exception.
+     */
+    @Test
+    public void testAppWarmStartWithoutEngagementTime() throws Exception {
+        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_START);
+        Activity activityA = mock(ActivityA.class);
+
+        Bundle bundle = mock(Bundle.class);
+        callbacks.onActivityCreated(activityA, bundle);
+        callbacks.onActivityStarted(activityA);
+        callbacks.onActivityResumed(activityA);
+        callbacks.onActivityPaused(activityA);
+        callbacks.onActivityDestroyed(activityA);
+
+        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_STOP);
+        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_START);
+
+        Activity activityA1 = mock(ActivityA.class);
+        callbacks.onActivityCreated(activityA1, bundle);
+        callbacks.onActivityStarted(activityA1);
+        callbacks.onActivityResumed(activityA1);
+
+        try (Cursor cursor = dbUtil.queryAllEvents()) {
+            cursor.moveToLast();
+            String eventString = cursor.getString(2);
+            JSONObject jsonObject = new JSONObject(eventString);
+            String eventName = jsonObject.getString("event_type");
+            assertEquals(Event.PresetEvent.SCREEN_VIEW, eventName);
+            JSONObject attributes = jsonObject.getJSONObject("attributes");
+            Assert.assertFalse(attributes.has(ReservedAttribute.ENGAGEMENT_TIMESTAMP));
+        }
+    }
 
     /**
      * test app version not update.