How to get currently visible index in RN flat list

Question

I have a horizontal flat list where each item is width:300 All I am trying to do is to get index of currently visible item.

Answer 1

Many thanks to the most-voted answer :) However, it does not work when I try it, raising an error saying that changing onViewableItemsChanged on the fly is not supported. After some search, I find the solution here. Here is the full code that can run without error. The key point is that the two configs should be put as class properties instead of inside the render() function.

class MyComponent extends Component {  
  _onViewableItemsChanged = ({ viewableItems, changed }) => {
    console.log("Visible items are", viewableItems);
    console.log("Changed in this iteration", changed);
  };

  _viewabilityConfig = {
    itemVisiblePercentThreshold: 50
  };

  render() {
    return (
        
      
    );
  }
}