Respond to Android FlatList to Android Animation

Question

I have a FlatList with an onScroll function that looks like this:

<Animated.View style={{ transform: [{translateX: this.state.scrollX}] }}>
  <FlatList
    data={ reactionGroup.reactions }
    keyExtractor={ (i) => i.id + uuid.v4() }
    renderItem={ this._renderItem }
    horizontal={ true }
    scrollEventThrottle={1}
    onScroll={ reactionGroup.reactions.length > 1 ? this.onScroll : null }
    showsHorizontalScrollIndicator={ false } />
</Animated.View>

onScroll(event) {
  const { timing } = Animated
  if (event.nativeEvent.contentOffset.x > 0) {
    timing(
      this.state.scrollX,
      { toValue: -60, duration: 100, useNativeDriver: true }
    ).start()
  } else {
    timing(
      this.state.scrollX,
      { toValue: 0, duration: 100, useNativeDriver: true }
    ).start()
  }
},

This works fine on iOS, but for Android, the animation won't start until FlatList stops scrolling.

Basically, I just start the animation when the user scrolls and sets it back when they return to the beginning of the horizontal scroll.

Is there a better way to handle this, so it works on Android?

I also tried doing Animation.event inside onScroll, but I don't want to snap the animation directly to the scroll position. This approach allowed Android to animate while scrolling, but it was pretty nervous.

RN: 0.43.3

Answer 1

Animated.event. , event.nativeEvent .

blogpost , nav RN:

https://medium.com/appandflow/react-native-collapsible-navbar-e51a049b560a

, : -)