feat: fire the onTouchStart prop

[sangle7]

Platforms affected

all

What does this PR do?

fire the onTouchStart prop in carousel

the onTouchStart prop didn't fire in the previous code, which may end in unwanted result.

an online demo here: https://snack.expo.io/@sanglewang/react-native-snap-carousel-demo

in the case, we have two nested vertical scrollview, on android only the outside scroll view can be scrolled. we add a state to control the scrollEnabled prop to hack it. since the onTouchStart prop did not fire in the carousel, the state will never turn to false, and the carousel cannot mannully scroll.

I was wondering why the other event props (onScrollEndDrag, onMomentumScrollEnd etc. ) are fired in the component and the onTouchStart is not. Is there any protential problem i ignored ?

What testing has been done on this change?

Tested features checklist

• Default setup (example)
• Carousels with and without momentum enabled (prop enableMomentum)
• Vertical carousels (prop vertical)
• Slide alignment (prop activeSlideAlignment)
• Autoplay (prop autoplay)
• Loop mode (prop loop)
• ScrollView/FlatList carousels (prop useScrollView)
• Callback methods
• ParallaxImage component
• Pagination component
• Layouts and custom interpolations

[bd-arc]

Hi @sangle7,

Thank you for the PR!

Well, there shouldn't be any issue in theory, but I remember seeing weird things with the autoplay feature...

Have you made sure that the autoplay was still working properly on iOS and Android when a onTouchStart callback was defined?

[sangle7]

yes, i've tested on both Android and iOS device. Autoplay works well.😃

[bd-arc]

Shipped in version 3.8.0.