react-horizontal-scrolling-menu

桌面端滑动：一个给菜单翻页的鼠标轻拂

拖拽滚动让这一行 1:1 地跟随光标。这是另一种鼠标手势：轻拂。按下、移动至少 50px、松开——菜单便通过 scrollNext 或 scrollPrev 朝那个方向滑行一页。这一行完全不会跟随指针；滑行是库的平滑程序化滚动，正是它让松开的动作带有惯性感。
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在这一行任意位置按下，向左或向右移动至少 50px 再松开——菜单滑行一页。更短的移动不会产生效果。

在 Storybook 中实时编辑此示例

工作原理

一个 useSwipe hook 返回 ScrollMenu 期待的三个柯里化鼠标属性——每个都接收 API 对象并返回普通的事件处理器。onMouseDown 把指针的 clientX 锚定到一个 ref 里，onMouseMove 不断覆盖结束坐标，onMouseUp 则比较二者：超过 minSwipeDistance（50px）的水平差值，向左轻拂调用 apiObj.scrollNext()，向右则调用 apiObj.scrollPrev()。

为什么点击无需特殊处理

在拖拽滚动示例里，在卡片上松开拖拽会点击它，所以 dragging 标志必须比手势多存活一帧。轻拂把整个问题绕开了：低于 50px 阈值时 onMouseUp 什么都不做，点击就只是点击——超过阈值时指针反正也已经离开了它按下的那张卡片。没有标志，没有受抑制的处理器。

这个 story 为触摸与滚轮补充了什么

该 story 也敲定了原生触摸平移：React 18+ 以被动方式注册 touchmove 监听器，因此 preventDefault 只能从非被动监听器里生效。一个副作用通过 apiRef（ref.current.scrollContainer.current）拿到滚动容器，并以 { passive: false } 附加一个监听器。它的 onWheel 处理器也会给菜单翻页，并带一条启发式规则——非零 deltaX 或较小的 deltaY 被视为触控板而放行。

注意

完整源码

完整且可直接复制粘贴——这正是背后这份文件的 可在 Storybook 中实时编辑的版本.

SwipeDesktop.source.tsx
import 'react-horizontal-scrolling-menu/dist/styles.css';

import styled from '@emotion/styled';
import React from 'react';
import {
  type publicApiType,
  ScrollMenu,
  VisibilityContext,
} from 'react-horizontal-scrolling-menu';

export function SwipeDesktop() {
  const [items] = React.useState(() => getItems());
  const [selected, setSelected] = React.useState<string[]>([]);

  const isItemSelected = (id: string): boolean =>
    !!selected.find((el) => el === id);

  const handleItemClick = (itemId: string) => {
    const itemSelected = isItemSelected(itemId);

    setSelected((currentSelected: string[]) =>
      itemSelected
        ? currentSelected.filter((el) => el !== itemId)
        : currentSelected.concat(itemId),
    );
  };

  const { onMouseDown, onMouseMove, onMouseUp } = useSwipe();

  const ref = React.useRef<publicApiType>(null);

  // React 18+ attaches touchmove listeners as passive, so preventDefault only
  // works from a non-passive listener added manually to the scroll container.
  React.useEffect(() => {
    const onTouchMove = (ev: TouchEvent) => {
      ev.preventDefault();
    };
    const node = ref.current?.scrollContainer.current;
    node?.addEventListener('touchmove', onTouchMove, { passive: false });

    return () => node?.removeEventListener('touchmove', onTouchMove);
  }, [ref]);

  return (
    <NoScrollbar>
      <ScrollMenu
        LeftArrow={LeftArrow}
        RightArrow={RightArrow}
        onWheel={onWheel}
        onMouseDown={onMouseDown}
        onMouseMove={onMouseMove}
        onMouseUp={onMouseUp}
        apiRef={ref}
      >
        {items.map(({ id }) => (
          <Card
            title={id}
            itemId={id} // NOTE: itemId is required for track items
            key={id}
            onClick={() => handleItemClick(id)}
            selected={isItemSelected(id)}
          />
        ))}
      </ScrollMenu>
    </NoScrollbar>
  );
}

export default SwipeDesktop;

export const useSwipe = () => {
  const pos = React.useRef({ start: { x: 0, y: 0 }, end: { x: 0, y: 0 } });

  // the required distance between touchStart and touchEnd to be detected as a swipe
  const minSwipeDistance = 50;

  const onMouseDown = () => (ev: React.MouseEvent) => {
    pos.current.start = { x: ev.clientX, y: ev.clientY };
  };

  const onMouseMove = () => (ev: React.MouseEvent) => {
    pos.current.end = { x: ev.clientX, y: ev.clientY };
  };

  const onMouseUp = (apiObj: publicApiType) => () => {
    // disable it for native touch screen devices
    // if ('ontouchstart' in window) { return false }

    const horDiff = pos.current.end.x - pos.current.start.x;
    // const vertDiff = pos.current.end.y - pos.current.start.y;
    const toLeft = horDiff < 0 && Math.abs(horDiff) > minSwipeDistance;
    const toRight = horDiff > 0 && Math.abs(horDiff) > minSwipeDistance;

    // for vertical menu
    // const toTop =  vertDiff < 0 && Math.abs(vertDiff) > minSwipeDistance;
    // const toBottom = vertDiff > 0 && Math.abs(vertDiff) > minSwipeDistance;

    if (toLeft) {
      apiObj.scrollNext();
    }
    if (toRight) {
      apiObj.scrollPrev();
    }
  };

  return { onMouseDown, onMouseMove, onMouseUp };
};

const NoScrollbar = styled('div')({
  '&': {
    position: 'relative',
  },
  '& .react-horizontal-scrolling-menu--scroll-container::-webkit-scrollbar': {
    display: 'none',
  },
  '& .react-horizontal-scrolling-menu--scroll-container': {
    scrollbarWidth: 'none',
    '-ms-overflow-style': 'none',
  },
});

function LeftArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);

  const disabled = visibility.useLeftArrowVisible();

  return (
    <Arrow
      disabled={disabled}
      onClick={() => visibility.scrollPrev()}
      testId="left-arrow"
    >
      Left
    </Arrow>
  );
}

function RightArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);

  const disabled = visibility.useRightArrowVisible();

  return (
    <Arrow
      disabled={disabled}
      onClick={() => visibility.scrollNext()}
      testId="right-arrow"
    >
      Right
    </Arrow>
  );
}

function Arrow({
  children,
  disabled,
  onClick,
  className,
  testId,
}: {
  children: React.ReactNode;
  disabled: boolean;
  onClick: VoidFunction;
  className?: string;
  testId: string;
}) {
  return (
    <ArrowButton
      disabled={disabled}
      onClick={onClick}
      className={'arrow' + `-${className}`}
      data-testid={testId}
    >
      {children}
    </ArrowButton>
  );
}
const ArrowButton = styled('button')((props) => ({
  cursor: 'pointer',
  display: 'flex',
  flexDirection: 'column',
  justifyContent: 'center',
  marginBottom: '2px',
  opacity: props.disabled ? '0' : '1',
  userSelect: 'none',
  borderRadius: '6px',
  borderWidth: '1px',
}));

function Card({
  onClick,
  selected,
  title,
  itemId,
}: {
  onClick: (context: publicApiType) => void;
  selected: boolean;
  title: string;
  itemId: string;
}) {
  const visibility = React.useContext<publicApiType>(VisibilityContext);
  const isVisible = visibility.useIsVisible(itemId, true);

  return (
    <CardBody
      data-cy={itemId}
      onClick={() => onClick(visibility)}
      onKeyDown={(ev: React.KeyboardEvent) => {
        ev.code === 'Enter' && onClick(visibility);
      }}
      data-testid="card"
      role="button"
      tabIndex={0}
      className="card"
      visible={isVisible}
      selected={selected}
    >
      <div className="header">
        <div>{title}</div>
        <div className="visible">visible: {JSON.stringify(isVisible)}</div>
        <div className="selected">selected: {JSON.stringify(!!selected)}</div>
      </div>
      <div className="background" />
    </CardBody>
  );
}
const CardBody = styled('div')<{ selected?: boolean; visible?: boolean }>(
  (props) => ({
    border: '1px solid',
    display: 'inline-block',
    margin: '0 10px',
    width: '160px',
    userSelect: 'none',
    borderRadius: '8px',
    overflow: 'hidden',

    '& .header': {
      backgroundColor: 'white',
    },

    '& .visible': {
      backgroundColor: props.visible ? 'transparent' : 'gray',
    },

    '& .background': {
      backgroundColor: props.selected ? 'green' : 'bisque',
      height: '200px',
    },
  }),
);

const getId = (index: number) => `${'test'}${index}`;

const getItems = () =>
  Array(20)
    .fill(0)
    .map((_, ind) => ({ id: getId(ind) }));

function onWheel(apiObj: publicApiType, ev: React.WheelEvent): void {
  // NOTE: no good standart way to distinguish touchpad scrolling gestures
  // but can assume that gesture will affect X axis, mouse scroll only Y axis
  // of if deltaY too small probably is it touchpad
  const isThouchpad = Math.abs(ev.deltaX) !== 0 || Math.abs(ev.deltaY) < 15;

  if (isThouchpad) {
    ev.stopPropagation();
    return;
  }

  if (ev.deltaY < 0) {
    apiObj.scrollNext();
  } else {
    apiObj.scrollPrev();
  }
}

相关示例

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