Make sure that `onSnapToItem` is triggered AFTER scroll animation's completion

Currently, React Native doesn’t provide a callback for the scrollTo() method, which is a bummer.

The ScrollView component has a prop onScrollAnimationEnd, but unfortunately this works on iOS only (even though it is referenced in the Java file). Moreover, a bug currently prevents the callback from being fired with horizontal scrollers.

Another lead would be to link the duration of the scroll animation to a timer before firing the callback. Unfortunately, scrollTo() doesn’t accept a custom duration.

An idea might be to activate momentum events on Android and see if onMomentumScrollEnd can provide a good enough feedback without impairing performance too much. But this event might not be fired when snapping programatically… Moreover, it is automatically enabled if a momentum callback has been set.

ScrollResponder is another lead worth pursuing…

[joseygordev]

@bd-arc thank you very much for you attention, component very nice.

[bd-arc]

@piuccio @joseygordev Version 2.2.1 should resolve your issue with the faulty index.

I’ve completely refactored the way callbacks are handled when momentum is disabled. Let’s face it: this is hacky since ScrollView neither provides callbacks to the scrollTo method nor gives access to a onScrollEnd event.

Make sure to play with the new props scrollEndDragThrottleValue and snapCallbackDebounceValue. Let me know how this works for you.