警报

一个用于呈现原生 iOS 警报对话框的 SwiftUI Alert 组件。

iOS

tvOS

Included in Expo Go

GitHub

npm

更新日志

Recommended version:

~57.0.0

Expo UI Alert 与官方 SwiftUI alert API 保持一致，并会展示一个原生 iOS 警告对话框，包含标题、操作，以及可选的消息。

Alert 是 ConfirmationDialog 的居中模态对应组件，后者会以从屏幕底部弹出的操作表形式渲染。两者共享相同的触发器/操作/消息槽位模型，因此调用方只需更改组件名称即可在它们之间切换。

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

基本警告框

使用 Alert.Trigger 定义可见元素，使用 Alert.Actions 提供对话框按钮。

BasicAlertExample.tsx

import { useState } from 'react';
import { Host, Alert, Button } from '@expo/ui/swift-ui';

export default function BasicAlertExample() {
  const [isPresented, setIsPresented] = useState(false);

  return (
    <Host matchContents>
      <Alert title="已保存" isPresented={isPresented} onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button label="显示警告框" onPress={() => setIsPresented(true)} />
        </Alert.Trigger>
        <Alert.Actions>
          <Button label="确定" onPress={() => setIsPresented(false)} />
        </Alert.Actions>
      </Alert>
    </Host>
  );
}

取消与确认

将 role="cancel" 与确认按钮结合，构建标准的是否确认警告框。

CancelConfirmAlertExample.tsx

import { useState } from 'react';
import { Host, Alert, Button, Text } from '@expo/ui/swift-ui';

export default function CancelConfirmAlertExample() {
  const [isPresented, setIsPresented] = useState(false);

  return (
    <Host matchContents>
      <Alert title="要退出登录吗？" isPresented={isPresented} onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button label="退出登录" onPress={() => setIsPresented(true)} />
        </Alert.Trigger>
        <Alert.Actions>
          <Button label="退出登录" onPress={() => console.log('Signed out')} />
          <Button label="取消" role="cancel" />
        </Alert.Actions>
        <Alert.Message>
          <Text>你需要重新登录才能访问你的账户。</Text>
        </Alert.Message>
      </Alert>
    </Host>
  );
}

危险操作

在 Alert.Actions 内的 Button 上使用 role="destructive"，将其样式设为危险操作。

DestructiveAlertExample.tsx

import { useState } from 'react';
import { Host, Alert, Button, Text } from '@expo/ui/swift-ui';

export default function DestructiveAlertExample() {
  const [isPresented, setIsPresented] = useState(false);

  return (
    <Host matchContents>
      <Alert title="要删除账户吗？" isPresented={isPresented} onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button label="删除账户" role="destructive" onPress={() => setIsPresented(true)} />
        </Alert.Trigger>
        <Alert.Actions>
          <Button
            label="删除"
            role="destructive"
            onPress={() => {
              console.log('已删除');
              setIsPresented(false);
            }}
          />
          <Button label="取消" role="cancel" />
        </Alert.Actions>
        <Alert.Message>
          <Text>这将永久删除你的账户及所有数据。此操作无法撤销。</Text>
        </Alert.Message>
      </Alert>
    </Host>
  );
}

API

import { Alert } from '@expo/ui/swift-ui';

Component

`Alert`

Type: React.Element<AlertProps>

Alert presents a SwiftUI alert with a title, optional message, and action buttons.

See: Official SwiftUI documentation.

Props of the Alert component.

AlertProps

`children`

Type: React.ReactNode

The contents of the alert. Should include Alert.Trigger, Alert.Actions, and optionally Alert.Message.

`isPresented`

Optional • Type: boolean

Whether the alert is presented.

`onIsPresentedChange`

Optional • Type: (isPresented: boolean) => void

A callback that is called when the isPresented state changes.

`title`

Type: string

The title of the alert.

Inherited props

CommonViewModifierProps