Ali72 · September 20, 2024 13:03
diff --git a/HorizontalRTLSupportFlatList.js b/HorizontalRTLSupportFlatList.js
 import React, {useEffect, useRef, useState} from 'react';
 import {FlatList, I18nManager} from 'react-native';

 /**
 * HorizontalRTLSupportFlatList
 *
 * This component is a custom wrapper around React Native's FlatList to add support
 * for Right-to-Left (RTL) layouts when rendering horizontal lists. It automatically
 * handles reversing the scroll direction and item order in RTL mode while maintaining
 * the correct visual order of list items. Additionally, it includes logic to manage
 * scrolling behavior in large screens and to handle potential scroll failures.
 *
 * Why this component was created:
 * - React Native's FlatList does not provide native RTL scrolling for horizontal lists.
 * - This component ensures correct scrolling direction and item order in RTL layouts.
 * - It solves the need for a reusable RTL-friendly horizontal FlatList component.
 *
 * Key Features:
 * - Automatically flips the FlatList's horizontal scrolling in RTL mode by reversing the data and using the `inverted` prop.
 * - Reverses the data array to display items in the correct visual order for RTL layouts.
 * - Scrolls to the last item in RTL mode (or the first item in LTR mode) after the layout is complete.
 * - Adjusts the scroll offset to center the selected item for large screens.
 * - Handles potential `scrollToIndex` failures by using `onScrollToIndexFailed` to retry scrolling after a small delay.
 *
 * Scroll Behavior:
 * - Uses the `inverted` prop to flip the scrolling direction in RTL mode without the need for a `scaleX` transformation.
 * - Scrolls to the last item in RTL mode once the layout is complete and retries scrolling on failure.
 * - Adjusts the scroll offset on large screens for better centering of items.
 */

 const HorizontalRTLSupportFlatList = ({renderItem, data, ...props}) => {
  const flatListRef = useRef(null); // Reference for accessing FlatList methods like scrollToIndex
  const [isLayoutComplete, setIsLayoutComplete] = useState(false); // Tracks whether the FlatList has completed layout
  const [isScrollToIndexFailed, setScrollToIndexFailed] = useState(false); // Tracks if scrollToIndex has failed

  // Reverse the data if RTL mode is active to ensure the correct visual order of items.
  const processedData = I18nManager.isRTL ? [...data].reverse() : data;

  useEffect(() => {
    // Scroll to the last item in RTL mode after the layout is complete
    if (I18nManager.isRTL && isLayoutComplete && flatListRef.current && processedData.length > 0) {
      flatListRef.current.scrollToIndex({index: processedData.length - 1, animated: false});
    }
  }, [isLayoutComplete, isScrollToIndexFailed, processedData]);

  return (
    <FlatList
      ref={flatListRef} // Ref to programmatically control FlatList
      horizontal // Specifies horizontal list layout
      inverted={I18nManager.isRTL} // Inverts scrolling in RTL mode
      data={processedData} // Use processed (reversed) data for correct RTL order
      {...props} // Spread other props like keyExtractor, extraData, etc.
      renderItem={renderItem} // Function to render each item in the list
      onLayout={() => setIsLayoutComplete(true)} // Trigger layout completion callback
      onScrollToIndexFailed={info => {
        // Handle scrollToIndex failure and retry after a short delay
        const wait = new Promise(resolve => setTimeout(resolve, 200));
        wait.then(() => {
          setScrollToIndexFailed(true);
        });
      }}
    />
  );
 };

 export default HorizontalRTLSupportFlatList;
	import React, {useEffect, useRef, useState} from 'react';
	import {FlatList, I18nManager} from 'react-native';

	/**
	* HorizontalRTLSupportFlatList
	*
	* This component is a custom wrapper around React Native's FlatList to add support
	* for Right-to-Left (RTL) layouts when rendering horizontal lists. It automatically
	* handles reversing the scroll direction and item order in RTL mode while maintaining
	* the correct visual order of list items. Additionally, it includes logic to manage
	* scrolling behavior in large screens and to handle potential scroll failures.
	*
	* Why this component was created:
	* - React Native's FlatList does not provide native RTL scrolling for horizontal lists.
	* - This component ensures correct scrolling direction and item order in RTL layouts.
	* - It solves the need for a reusable RTL-friendly horizontal FlatList component.
	*
	* Key Features:
	* - Automatically flips the FlatList's horizontal scrolling in RTL mode by reversing the data and using the `inverted` prop.
	* - Reverses the data array to display items in the correct visual order for RTL layouts.
	* - Scrolls to the last item in RTL mode (or the first item in LTR mode) after the layout is complete.
	* - Adjusts the scroll offset to center the selected item for large screens.
	* - Handles potential `scrollToIndex` failures by using `onScrollToIndexFailed` to retry scrolling after a small delay.
	*
	* Scroll Behavior:
	* - Uses the `inverted` prop to flip the scrolling direction in RTL mode without the need for a `scaleX` transformation.
	* - Scrolls to the last item in RTL mode once the layout is complete and retries scrolling on failure.
	* - Adjusts the scroll offset on large screens for better centering of items.
	*/

	const HorizontalRTLSupportFlatList = ({renderItem, data, ...props}) => {
	const flatListRef = useRef(null); // Reference for accessing FlatList methods like scrollToIndex
	const [isLayoutComplete, setIsLayoutComplete] = useState(false); // Tracks whether the FlatList has completed layout
	const [isScrollToIndexFailed, setScrollToIndexFailed] = useState(false); // Tracks if scrollToIndex has failed

	// Reverse the data if RTL mode is active to ensure the correct visual order of items.
	const processedData = I18nManager.isRTL ? [...data].reverse() : data;

	useEffect(() => {
	// Scroll to the last item in RTL mode after the layout is complete
	if (I18nManager.isRTL && isLayoutComplete && flatListRef.current && processedData.length > 0) {
	flatListRef.current.scrollToIndex({index: processedData.length - 1, animated: false});
	}
	}, [isLayoutComplete, isScrollToIndexFailed, processedData]);

	return (
	<FlatList
	ref={flatListRef} // Ref to programmatically control FlatList
	horizontal // Specifies horizontal list layout
	inverted={I18nManager.isRTL} // Inverts scrolling in RTL mode
	data={processedData} // Use processed (reversed) data for correct RTL order
	{...props} // Spread other props like keyExtractor, extraData, etc.
	renderItem={renderItem} // Function to render each item in the list
	onLayout={() => setIsLayoutComplete(true)} // Trigger layout completion callback
	onScrollToIndexFailed={info => {
	// Handle scrollToIndex failure and retry after a short delay
	const wait = new Promise(resolve => setTimeout(resolve, 200));
	wait.then(() => {
	setScrollToIndexFailed(true);
	});
	}}
	/>
	);
	};

	export default HorizontalRTLSupportFlatList;