Screen event recorded is out of sync if a event is fired right before a screen view event

[drayan85]

Describe the bug

Especially when an event is triggered right before an activity navigation.

We suspect it is because screen_view event from the track method is collected in an Executor thread.

https://github.com/snowplow/snowplow-android-tracker/blob/1.7.1/snowplow-tracker/src/main/java/com/snowplowanalytics/snowplow/tracker/Tracker.java#L534-L538

However, the tracking of screen_view is not done in the Executor thread.

https://github.com/snowplow/snowplow-android-tracker/blob/1.7.1/snowplow-tracker/src/main/java/com/snowplowanalytics/snowplow/tracker/Tracker.java#L528-L531

So it is possible for the recording of screen_view to be executed first. By the time the previous track method retrieves the screen_view context, it is already out of date.

To Reproduce
Steps to reproduce the behavior or code snippets that produce the issue.

Tracker.TrackerBuilder trackerBuilder = new Tracker.TrackerBuilder(/** **/);
Tracker snowPlowTracker = Tracker.init(trackerBuilder.build());

// In ActivityA.onResume()
ScreenView.Builder<?> screenView = ScreenView.builder()
        .activityClassName("ActivityA")
        .name("ActivityA")
        .build();
snowPlowTracker.track(screenView); // seq 1

// User presses a button to navigate to ActivityB

Structured.Builder<?> builder = Structured.builder()
    .category("navigate")
    .label("ActivityB")
    .build();
snowPlowTracker.track(builder); // seq 2

// Start ActivityB

// In ActivityB.onResume()

ScreenView.Builder<?> screenView = ScreenView.builder()
        .activityClassName("ActivityB")
        .name("ActivityB")
        .build();
snowPlowTracker.track(screenView); // seq 3

Expected behavior

seq	event.type	screen.activity	screen_view.name	structEvent.category	structEvent.label
1	screen_view	ActivityA	ActivityA
2	event	ActivityA	ActivityA	navigate	ActivityB
3	screen_view	ActivityB	ActivityB

But what we observed is:

seq	event.type	screen.activity	screen_view.name	structEvent.category	structEvent.label
1	screen_view	ActivityA	ActivityA
2	event	ActivityB	ActivityB	navigate	ActivityB
3	screen_view	ActivityB	ActivityB

Notice that seq2 is recorded as if it is triggered from the next screen (ActivityB).

Screenshots
N/A

Device informatoin (please complete the following information):

• Device: In All Tested Android Devices (Oneplus 6, Pixel 4, Razer)
• OS: Android9, Android 10, Android 11
• Version: SnowPlow 1.7.1

Additional context

• We did not enable screenviewEvents to auto record the screen views (.screenviewEvents(false))

[AlexBenny]

Thanks @drayan85 to raise this issue.
We noticed the problem and planned a fix that would improve all the internal state management of the tracker.
We are close to release the version 2.0 of both iOS and Android trackers.
Just after that we will work on this fix in one of the minor versions we planned.
I don't have a clear ETA at the moment. I'll keep you updated here about further details on that.

[drayan85]

@AlexBenny, Thanks for your reply and Please update when this fix added to the release so we can update our mobile SDKs respectively.