This is documentation for the next SDK version. For up-to-date documentation, see the latest version (SDK 55).

LazyColumn

一个用于显示可滚动列表的 Jetpack Compose LazyColumn 组件。

Android

GitHub

npm

更新日志

一个懒加载的垂直列表组件，它只渲染可见项，以实现高效滚动。有关更多信息，请参阅 Jetpack Compose 官方文档。

安装

Terminal

- npx 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

基础懒加载列

BasicLazyColumn.tsx

import { Host, LazyColumn, ListItem } from '@expo/ui/jetpack-compose';

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

export default function BasicLazyColumn() {
  return (
    <Host style={{ height: 400 }}>
      <LazyColumn>
        {items.map(item => (
          <ListItem key={item} headline={item} />
        ))}
      </LazyColumn>
    </Host>
  );
}

使用排列方式

使用 verticalArrangement 属性来控制列表中各项的间距。传入一个字符串值，例如 'spaceBetween'，或者传入一个对象，例如 { spacedBy: 8 }，以设置固定的 dp 间距。

LazyColumnArrangement.tsx

import { Host, LazyColumn, ListItem } from '@expo/ui/jetpack-compose';

export default function LazyColumnArrangement() {
  return (
    <Host style={{ height: 400 }}>
      <LazyColumn verticalArrangement={{ spacedBy: 8 }} horizontalAlignment="center">
        <ListItem>
          <ListItem.HeadlineContent>间隔项 1</ListItem.HeadlineContent>
        </ListItem>
        <ListItem>
          <ListItem.HeadlineContent>间隔项 2</ListItem.HeadlineContent>
        </ListItem>
        <ListItem>
          <ListItem.HeadlineContent>间隔项 3</ListItem.HeadlineContent>
        </ListItem>
      </LazyColumn>
    </Host>
  );
}

使用内容内边距

使用 contentPadding 属性为列表内容周围添加 dp 内边距。

LazyColumnPadding.tsx

import { Host, LazyColumn, ListItem } from '@expo/ui/jetpack-compose';

export default function LazyColumnPadding() {
  return (
    <Host style={{ height: 400 }}>
      <LazyColumn contentPadding={{ start: 16, top: 8, end: 16, bottom: 8 }}>
        <ListItem>
          <ListItem.HeadlineContent>带内边距的项 1</ListItem.HeadlineContent>
        </ListItem>
        <ListItem>
          <ListItem.HeadlineContent>带内边距的项 2</ListItem.HeadlineContent>
        </ListItem>
        <ListItem>
          <ListItem.HeadlineContent>带内边距的项 3</ListItem.HeadlineContent>
        </ListItem>
      </LazyColumn>
    </Host>
  );
}

API

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

Component

`LazyColumn`

Android

Type: React.Element<LazyColumnProps>

A lazy column component that efficiently displays a vertically scrolling list.

LazyColumnProps

`children`

Android

Optional • Type: React.ReactNode

The content to display inside the lazy column.

`contentPadding`

Android

Optional • Type: ContentPadding

Content padding in dp.

`horizontalAlignment`

Android

Optional • Literal type: string

The horizontal alignment of items.

Acceptable values are: 'start' | 'end' | 'center'

`modifiers`

Android

Optional • Type: ExpoModifier[]

Modifiers for the component.

`verticalArrangement`

Android

Optional • Literal type: union

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

Acceptable values are: 'top' | 'bottom' | 'center' | 'spaceBetween' | 'spaceAround' | 'spaceEvenly' | { spacedBy: number }

Types

`ContentPadding`

Android

Content padding values for LazyColumn.

Property	Type	Description
bottom(optional)	`number`	Bottom padding in dp.
end(optional)	`number`	End padding in dp.
start(optional)	`number`	Start padding in dp.
top(optional)	`number`	Top padding in dp.