图片

用于显示 SF 符号的 SwiftUI 图片组件。

iOS

tvOS

Included in Expo Go

Recommended version:

~57.0.3

信息有关跨平台使用，请参阅通用 Icon —— 它会根据平台呈现相应的原生组件。

Expo UI 图片使用 SwiftUI Image API 显示 SF 符号。SF 符号是苹果提供的一个可配置符号库。

🌐 Expo UI Image displays SF Symbols using the SwiftUI Image API. SF Symbols are a library of configurable symbols provided by Apple.

安装

🌐 Installation

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

🌐 Usage

基本 SF 符号

🌐 Basic SF Symbol

BasicImageExample.tsx

import { Host, Image } from '@expo/ui/swift-ui';

export default function BasicImageExample() {
  return (
    <Host matchContents>
      <Image systemName="star.fill" />
    </Host>
  );
}

自定义 SF 符号

🌐 Custom SF Symbol

使用 assetName 属性来显示作为符号集导入到应用资源目录中的自定义 SF 符号。

🌐 Use the assetName prop to display a custom SF Symbol imported into the app asset catalog as a symbol set.

CustomImageExample.tsx

import { Host, Image } from '@expo/ui/swift-ui';

export default function CustomImageExample() {
  return (
    <Host matchContents>
      <Image assetName="acme.mark" />
    </Host>
  );
}

按尺寸和颜色

🌐 With size and color

ImageSizeColorExample.tsx

import { Host, HStack, Image } from '@expo/ui/swift-ui';

export default function ImageSizeColorExample() {
  return (
    <Host matchContents>
      <HStack spacing={16}>
        <Image systemName="heart.fill" size={24} color="red" />
        <Image systemName="star.fill" size={32} color="orange" />
        <Image systemName="bell.fill" size={40} color="blue" />
      </HStack>
    </Host>
  );
}

带有变量值

🌐 With variable value

某些 SF 符号会根据变量值改变其外观。使用 variableValue 属性，取值范围在 0.0 到 1.0 之间，以控制渲染的符号。需要 iOS 16.0 及以上版本和 SF Symbols 4.0 及以上版本。

🌐 Some SF Symbols alter their appearance based on a variable value. Use the variableValue prop with a value between 0.0 and 1.0 to control the rendered symbol. Requires iOS 16.0+ and SF Symbols 4.0+.

ImageVariableExample.tsx

import { Host, HStack, Image } from '@expo/ui/swift-ui';

export default function ImageVariableExample() {
  return (
    <Host matchContents>
      <HStack spacing={16}>
        <Image systemName="chart.bar.fill" size={32} variableValue={0.3} />
        <Image systemName="chart.bar.fill" size={32} variableValue={0.6} />
        <Image systemName="chart.bar.fill" size={32} variableValue={1.0} />
      </HStack>
    </Host>
  );
}

带符号效果

🌐 With symbol effect

通过从 @expo/ui/swift-ui/modifiers 传递 symbolEffect 修饰符，为 SF 符号应用动画效果。默认情况下，此效果会连续运行。你也可以传递 value 来触发离散事件，每次更改时触发一次，或者传递 isActive 作为布尔切换，在 true 为真时运行此效果。需要 iOS 17.0 及更高版本。

🌐 Apply an SF Symbol effect to animate the symbol by passing a symbolEffect modifier from @expo/ui/swift-ui/modifiers. This effect runs continuously by default. You can also pass value for a discrete trigger that fires once per change, or isActive for a boolean toggle that runs the effect while true. Requires iOS 17.0 and later.

ImageSymbolEffectExample.tsx

import { Host, Image } from '@expo/ui/swift-ui';
import { symbolEffect } from '@expo/ui/swift-ui/modifiers';

export default function ImageSymbolEffectExample() {
  return (
    <Host matchContents>
      <Image
        systemName="wifi"
        size={48}
        color="blue"
        modifiers={[
          symbolEffect({
            effect: 'variableColor',
            fillStyle: 'iterative',
            playbackStyle: 'reversing',
          }),
        ]}
      />
    </Host>
  );
}

以下示例使用 value 在每次按下按钮时播放 bounce。从 worklet（或通过 scheduleOnUI）写入 state.value 以触发效果。

🌐 The following example uses value to play bounce on each button press. Write to state.value from a worklet (or via scheduleOnUI) to trigger the effect.

ImageSymbolEffectValueExample.tsx

import { Button, Host, Image, useNativeState, VStack } from '@expo/ui/swift-ui';
import { symbolEffect } from '@expo/ui/swift-ui/modifiers';
import { scheduleOnUI } from 'react-native-worklets';

export default function ImageSymbolEffectValueExample() {
  const trigger = useNativeState(0);

  return (
    <Host matchContents>
      <VStack spacing={16}>
        <Image
          systemName="bell.fill"
          size={48}
          color="orange"
          modifiers={[symbolEffect({ effect: 'bounce', direction: 'up' }, { value: trigger })]}
        />
        <Button
          label="Bounce"
          onPress={() =>
            scheduleOnUI(() => {
              'worklet';
              trigger.value = trigger.value + 1;
            })
          }
        />
      </VStack>
    </Host>
  );
}

以下示例使用 isActive 来切换连续的 breathe 动画。

🌐 The following example uses isActive to toggle a continuous breathe animation.

ImageSymbolEffectIsActiveExample.tsx

import { Host, Image, SyncToggle, useNativeState, VStack } from '@expo/ui/swift-ui';
import { symbolEffect } from '@expo/ui/swift-ui/modifiers';

export default function ImageSymbolEffectIsActiveExample() {
  const isActive = useNativeState(true);

  return (
    <Host matchContents>
      <VStack spacing={16}>
        <Image
          systemName="cloud.fill"
          size={48}
          color="cyan"
          modifiers={[symbolEffect({ effect: 'breathe' }, { isActive })]}
        />
        <SyncToggle label="Breathe" isOn={isActive} />
      </VStack>
    </Host>
  );
}

应用接口

🌐 API

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

Component

`Image`

Type: React.Element<ImageProps>

ImageProps

`assetName`

Optional • Type: string

The asset catalog name of a custom SF Symbol imported as a symbol set.

`color`

Optional • Type: ColorValue

The color of the system image. Can be a color name like '#ff00ff', 'red', 'blue', etc.

`onPress`

Optional • Type: () => void

Callback triggered when the view is pressed.

`size`

Optional • Type: number

The fixed size of the system image in points. Does not scale with Dynamic Type. Use the font modifier with textStyle for that. Ignored when a font modifier is supplied.

`systemName`

Optional • Type: SFSymbols7_0

The name of the system image (SF Symbol). For example: 'photo', 'heart.fill', 'star.circle'

`uiImage`

Optional • Type: string

The URI of the local image file to display. For example: 'file:///path/to/image.jpg' Performs a synchronous read operation that blocks the main thread.

`variableValue`

Only for:

iOS16.0+

tvOS16.0+

Optional • Type: number

The variable value that alters the symbol's appearance. A number between 0.0 and 1.0. Only works with SF Symbols that support variable values (SF Symbols 4.0+).

Inherited Props

CommonViewModifierProps