harmony 鸿蒙Arc Button (ArcButton)

2025-06-12
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Arc Button (ArcButton)

The ArcButton component represents an arc button specifically designed for circular screens on wearable devices. It offers various button styles, such as emphasized, normal, and warning, tailored for watch UIs. For details, see ArcButton.

Creating a Button

To create an ArcButton component, use the following:

ArcButton({
  options: new ArcButtonOptions({
    label: 'OK',
    position: ArcButtonPosition.TOP_EDGE,
    styleMode: ArcButtonStyleMode.EMPHASIZED_LIGHT
  })
})

label: sets the text displayed on the button.
position: sets the type of the button.
styleMode: sets the style mode of the button.

top

Setting the Button Type

The ArcButton component offers two types: top arc button and bottom arc button. Use the position attribute to set the type.

Lower arc button (default type)

Set position to ArcButtonPosition.BOTTOM_EDGE.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      position: ArcButtonPosition.BOTTOM_EDGE,
      styleMode: ArcButtonStyleMode.EMPHASIZED_LIGHT
    })
  })

bottom

Upper arc button

Set position to ArcButtonPosition.TOP_EDGE.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      position: ArcButtonPosition.TOP_EDGE,
      styleMode: ArcButtonStyleMode.EMPHASIZED_LIGHT
    })
  })

top

Customizing the Style

Setting the background color

Use the backgroundColor attribute to set the background color of the button.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      styleMode: ArcButtonStyleMode.CUSTOM,
      backgroundColor: ColorMetrics.resourceColor('#707070')
    })
  })

custom_bg

Setting the font color

Use the fontColor attribute to set the font color of the button.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      styleMode: ArcButtonStyleMode.CUSTOM,
      backgroundColor: ColorMetrics.resourceColor('#E84026'),
      fontColor: ColorMetrics.resourceColor('#707070')
    })
  })

custom_font

Setting the shadow color

Enable the button shadow using the shadowEnabled attribute and set the shadow color using the shadowColor attribute.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      shadowEnabled: true,
      shadowColor: ColorMetrics.resourceColor('#707070')
    })
  })

custom_shadow

Adding Events

Bind the onClick event to define custom behavior to be executed when the button is clicked.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      onClick: () => {
        console.info('ArcButton onClick')
      }
    })
  })

Bind the onTouch event to define custom behavior to be executed when the button is touched.

  ArcButton({
    options: new ArcButtonOptions({
      label: 'OK',
      onTouch: (event: TouchEvent) => {
        console.info('ArcButton onTouch')
      }
    })
  })

Example

This example demonstrates a brightness settings screen where a slider displays the current brightness level at 30%. When the reset button is clicked, the brightness value is reset to the default value of 50%.

import { LengthMetrics, LengthUnit, ArcButton, ArcButtonOptions, ArcButtonStyleMode, } from '@kit.ArkUI';

@Entry
@ComponentV2
struct BrightnessPage {
  @Local brightnessValue: number = 30
  private defaultBrightnessValue: number = 50

  build() {
    RelativeContainer() {
      Text('Set brightness')
        .fontColor(Color.Black)
        .id('id_brightness_set_text')
        .fontSize(24)
        .margin({ top: 16 })
        .alignRules({
          middle: { anchor: '__container__', align: HorizontalAlign.Center }
        })

      Text(`${this.brightnessValue} %`)
        .fontColor(Color.Black)
        .id('id_brightness_min_text')
        .margin({ left: 16 })
        .alignRules({
          start: { anchor: '__container__', align: HorizontalAlign.Start },
          center: { anchor: '__container__', align: VerticalAlign.Center }
        })

      Slider({
        value: this.brightnessValue,
        min: 0,
        max: 100,
        style: SliderStyle.InSet
      })
        .blockColor('#191970')
        .trackColor('#ADD8E6')
        .selectedColor('#4169E1')
        .width(150)
        .id('id_brightness_slider')
        .margin({ left: 16, right: 16 })
        .onChange((value: number, mode: SliderChangeMode) => {
          this.brightnessValue = value
        })
        .alignRules({
          center: { anchor: 'id_brightness_min_text', align: VerticalAlign.Center },
          start: { anchor: 'id_brightness_min_text', align: HorizontalAlign.End },
          end: { anchor: 'id_brightness_max_text', align: HorizontalAlign.Start }
        })

      ArcButton({
        options: new ArcButtonOptions({
          label: 'Reset',
          styleMode: ArcButtonStyleMode.EMPHASIZED_LIGHT,
          fontSize: new LengthMetrics(19, LengthUnit.FP),
          onClick: () => {
            this.brightnessValue = this.defaultBrightnessValue
          }
        })
      })
        .alignRules({
          middle: { anchor: '__container__', align: HorizontalAlign.Center },
          bottom: { anchor: '__container__', align: VerticalAlign.Bottom }
        })
    }
    .height('100%')
    .width('100%')
    .backgroundColor(Color.White)
  }
}

example