react-horizontal-scrolling-menu

一次滚动一个项目，而非整页

默认情况下箭头是翻页的：所有可见项滑出、下一组滑入。此示例把它们改接成一卡一步——每点一下一张卡——而整个改动就是箭头 onClick 所调用的内容。同样的菜单、同样的项目，不同的滚动目标。
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点击箭头——这一行前进一张卡，而非一页。箭头在两端禁用。

在 Storybook 中实时编辑此示例

工作原理

getNextElement() 返回可见组之后的第一个项目；getPrevElement() 返回它前面的那个。右箭头调用 scrollToItem(visibility.getNextElement(), ’smooth’, ’end’)——把那个项目对齐到容器的末尾边缘，滚动的距离恰好足以把它带进可视区，也就让这一行正好移动一张卡。左箭头与之对称：上一个元素，对齐到 ’start’。

对齐就是全部诀窍

现成的 scrollNext() 内部解析出同一个下一个元素，但把它对齐到起始边缘——视图会滚过整个可见组，把那个项目放到最前。一个 ScrollLogicalPosition 参数就区别了翻页与逐步。scrollToItem 的第三个参数是标准的 scroll-into-view inline 对齐；第二个是行为，这里是 ’smooth’。

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.

OneItemScroll.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 OneItemScroll() {
  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),
    );
  };

  return (
    <NoScrollbar>
      <ScrollMenu
        LeftArrow={LeftArrow}
        RightArrow={RightArrow}
        onWheel={onWheel}
      >
        {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 OneItemScroll;

function LeftArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);
  const isFirstItemVisible = visibility.useIsVisible('first', true);

  // NOTE: Look here
  const onClick = () =>
    visibility.scrollToItem(visibility.getPrevElement(), 'smooth', 'start');

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

function RightArrow() {
  const visibility = React.useContext<publicApiType>(VisibilityContext);
  const isLastItemVisible = visibility.useIsVisible('last', false);

  // NOTE: Look here
  const onClick = () =>
    visibility.scrollToItem(visibility.getNextElement(), 'smooth', 'end');

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

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

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(10)
    .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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