LazyRow

用于显示水平滚动列表的 Jetpack Compose LazyRow 组件。

Android

Included in Expo Go

GitHub

npm

更新日志

Recommended version:

~58.0.1

一种采用延迟加载的水平列表组件，仅渲染可见项目以实现高效滚动。有关更多信息，请参阅 Jetpack Compose 官方文档。

信息 LazyRow 目前还不是真正的延迟加载：原生端只会组合可见项目，但 React 仍会预先创建每个子项，因此大型列表的挂载速度可能较慢。我们正在努力改进这一点。对于大型列表，我们推荐使用 FlashList 或 Legend List。

安装

Terminal

- npx expo install @expo/ui

- yarn expo install @expo/ui

- pnpm expo install @expo/ui

- bun expo install @expo/ui

If you are installing this in an existing React Native app, make sure to install expo in your project.

用法

基本延迟加载行

BasicLazyRow.tsx

import {
  Host,
  LazyRow,
  Text,
  useMaterialColors,
} from '@expo/ui/jetpack-compose';
import {
  border,
  padding,
} from '@expo/ui/jetpack-compose/modifiers';

const items = Array.from(
  { length: 100 },
  (_, i) => `Item ${i + 1}`
);

export default function BasicLazyRow() {
  const colors = useMaterialColors();

  return (
    <Host style={{ height: 100 }}>
      <LazyRow>
        {items.map(item => (
          <Text
            key={item}
            style={{ fontSize: 28 }}
            color={colors.onBackground}
            modifiers={[
              border(1, colors.outline),
              padding(12, 6, 12, 6),
            ]}>
            {item}
          </Text>
        ))}
      </LazyRow>
    </Host>
  );
}

使用排列方式

使用 horizontalArrangement 属性控制列表中项目之间的间距。传入类似 'spaceBetween' 的字符串值，或传入类似 { spacedBy: 8 } 的对象以设置固定的 dp 间距。

LazyRowArrangement.tsx

import {
  Host,
  LazyRow,
  Text,
  useMaterialColors,
} from '@expo/ui/jetpack-compose';
import {
  border,
  padding,
} from '@expo/ui/jetpack-compose/modifiers';

export default function LazyRowArrangement() {
  const colors = useMaterialColors();

  return (
    <Host style={{ height: 100 }}>
      <LazyRow
        horizontalArrangement={{ spacedBy: 16 }}
        verticalAlignment="center">
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Spaced item 1
        </Text>
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Spaced item 2
        </Text>
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Spaced item 3
        </Text>
      </LazyRow>
    </Host>
  );
}

使用内容内边距

使用 contentPadding 属性以 dp 为单位在列表内容周围添加内边距。

LazyRowPadding.tsx

import {
  Host,
  LazyRow,
  Text,
  useMaterialColors,
} from '@expo/ui/jetpack-compose';
import {
  border,
  padding,
} from '@expo/ui/jetpack-compose/modifiers';

export default function LazyRowPadding() {
  const colors = useMaterialColors();

  return (
    <Host style={{ height: 100 }}>
      <LazyRow
        contentPadding={{ start: 16, top: 8, end: 16, bottom: 8 }}>
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Padded item 1
        </Text>
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Padded item 2
        </Text>
        <Text
          style={{ fontSize: 28 }}
          color={colors.onBackground}
          modifiers={[
            border(1, colors.outline),
            padding(12, 6, 12, 6),
          ]}>
          Padded item 3
        </Text>
      </LazyRow>
    </Host>
  );
}

API

import { LazyRow } from '@expo/ui/jetpack-compose';

Component

`LazyRow`

Android

Type: React.Element<LazyRowProps>

A lazy row component that efficiently displays a horizontally scrolling list.

LazyRowProps

`children`

Android

Optional • Type: ReactNode

The content to display inside the lazy row.

`contentPadding`

Android

Optional • Type: ContentPadding

Content padding in dp.

`horizontalArrangement`

Android

Optional • Literal type: union

The horizontal arrangement of items. Can be a preset string or an object with spacedBy to specify spacing in dp.

Acceptable values are: 'center' | 'start' | 'end' | 'spaceBetween' | 'spaceAround' | 'spaceEvenly' | { spacedBy: number }

`modifiers`

Android

Optional • Type: ModifierConfig[]

Modifiers for the component.

`verticalAlignment`

Android

Optional • Literal type: string

The vertical alignment of items.

Acceptable values are: 'center' | 'top' | 'bottom'