How to Achieve High‑Accuracy User Behavior Tracking in Flutter

User Behavior Tracking Positioning

In Xianyu's workflow a user enters page A, sees button X, clicks it, and a new page B opens. Five tracking events occur:

Enter page A – first frame rendered and focus gained.

Expose slot X – button X is visible on screen for a sufficient time.

Click slot X – user taps the button, triggering navigation to page B.

Leave page A – page A loses focus.

Enter page B – first frame rendered and focus gained.

Implementation Plan

Enter/Leave Page

Native apps listen to onResume / onPause (Android) or viewWillAppear / viewDidDisappear (iOS). In Flutter, pages are hosted by FlutterActivity or FlutterViewController, which maintain their own page stack, so native lifecycle hooks cannot be used directly.

Registering a NavigatorObserver to listen for push/pop events has two problems:

If page A is pushed, then page B is pushed and later popped, page A becomes visible again but no push event is received.

Dialogs or BottomSheets also trigger push events even though the underlying page has not left.

Solution: maintain an index list that mirrors the Flutter page stack. When a push event arrives, insert the new page index; when a pop occurs, remove the top index and trigger leave/enter events based on the remaining top page. For dialogs, check the overlayEntries of the Route and ignore non‑full‑screen overlays.

// Listen to scroll container offset
double _scrollContainerOffset = scrollNotification.metrics.pixels;

// Get offset of a widget relative to the screen
final RenderObject childRenderObject = context.findRenderObject();
final RenderAbstractViewport viewport = RenderAbstractViewport.of(childRenderObject);
if (viewport == null) return;
final RevealedOffset offsetToRevealTop = viewport.getOffsetToReveal(childRenderObject, 0.0);

Exposure Slot

A slot is considered exposed when:

At least half of its area is within the visible screen region.

It remains in the visible region for more than 500 ms.

To compute the visible proportion, obtain:

Container offset relative to the screen.

Slot offset relative to the container.

Slot dimensions.

Container dimensions.

if (slotIsInvisible && exposureRatio >= 0.5) {
  // mark as visible and record start time
} else if (slotIsVisible && exposureRatio < 0.5) {
  // mark as invisible
}
if (currentTime - startTime > 500ms) {
  // trigger exposure tracking API
}

Click Slot

Click tracking is straightforward: attach a listener to the widget and report the click event to the tracking backend.

Effect

After multiple iterations, the online Flutter page tracking accuracy has reached 100%, providing reliable data for business analysis. The solution is non‑intrusive: developers do not need to manually trigger page‑enter, page‑leave, or exposure events.

Future

Currently the solution works with Xianyu's Flutter‑Boost hybrid stack. As more pure Flutter pages appear, a native‑only implementation will be added to make the approach universally applicable.