Alert

用于呈现原生 iOS 警告对话框的 SwiftUI 警告组件。

iOS

tvOS

Included in Expo Go

GitHub

npm

更新日志

Recommended version:

~58.0.1

Expo UI Alert 与官方 SwiftUI alert API 相匹配，并呈现一个原生 iOS 警告对话框，包含标题、操作按钮和可选消息。

Alert 是 ConfirmationDialog 的居中模态对应组件，后者会从屏幕底部显示为操作表。两者使用相同的触发器/操作/消息插槽模型，因此调用方只需更改组件名称即可在两者之间切换。

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

基本警告

使用 Alert.Trigger 定义可见元素，并使用 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 style={{ flex: 1 }}>
      <Alert
        title="Saved"
        isPresented={isPresented}
        onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button
            label="Show alert"
            onPress={() => setIsPresented(true)}
          />
        </Alert.Trigger>
        <Alert.Actions>
          <Button
            label="OK"
            onPress={() => setIsPresented(false)}
          />
        </Alert.Actions>
      </Alert>
    </Host>
  );
}

取消和确认

结合使用 role="cancel" 和确认按钮，构建标准的是/否警告。

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 style={{ flex: 1 }}>
      <Alert
        title="Sign out?"
        isPresented={isPresented}
        onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button
            label="Sign out"
            onPress={() => setIsPresented(true)}
          />
        </Alert.Trigger>
        <Alert.Actions>
          <Button
            label="Sign out"
            onPress={() => console.log('Signed out')}
          />
          <Button label="Cancel" role="cancel" />
        </Alert.Actions>
        <Alert.Message>
          <Text>
            You will need to sign in again to access your account.
          </Text>
        </Alert.Message>
      </Alert>
    </Host>
  );
}

破坏性操作

在 Alert.Actions 内的 Button 上使用 role="destructive"，将其样式设为破坏性操作。

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 style={{ flex: 1 }}>
      <Alert
        title="Delete account?"
        isPresented={isPresented}
        onIsPresentedChange={setIsPresented}>
        <Alert.Trigger>
          <Button
            label="Delete account"
            role="destructive"
            onPress={() => setIsPresented(true)}
          />
        </Alert.Trigger>
        <Alert.Actions>
          <Button
            label="Delete"
            role="destructive"
            onPress={() => {
              console.log('Deleted');
              setIsPresented(false);
            }}
          />
          <Button label="Cancel" role="cancel" />
        </Alert.Actions>
        <Alert.Message>
          <Text>
            This permanently deletes your account and all data. This
            cannot be undone.
          </Text>
        </Alert.Message>
      </Alert>
    </Host>
  );
}

API

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

Component

`Alert`

iOS

tvOS

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`

iOS

tvOS

Type: React.ReactNode

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

`isPresented`

iOS

tvOS

Optional • Type: boolean

Whether the alert is presented.

`onIsPresentedChange`

iOS

tvOS

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

A callback that is called when the isPresented state changes.

`title`

iOS

tvOS

Type: string

The title of the alert.

Inherited props

CommonViewModifierProps