# Content Modifier

You can apply a content modifier to a component to customize its content area using a style builder.

>  **NOTE**
>
>  This feature is supported since API version 12. Updates will be marked with a superscript to indicate their earliest API version.

## contentModifier

contentModifier(modifier:ContentModifier\<T>)

Creates a content modifier.

**System capability**: SystemCapability.ArkUI.ArkUI.Full

**Parameters**

| Name  | Type              | Mandatory | Description                                                        |
| -------- | ------------------ | ---- | ------------------------------------------------------------ |
| modifier | ContentModifier\<T> | Yes  | Content modifier to apply to the current component.<br>**modifier**: content modifier. You need a custom class to implement the **ContentModifier** API. |

## ContentModifier\<T>

You need a custom class to implement the **ContentModifier** API.

### applyContent

applyContent() : WrappedBuilder<[T]>

Builder of the custom content area.

**Atomic service API**: This API can be used in atomic services since API version 12.

**Parameters**

| Name | Description                                                        |
| ---- | ------------------------------------------------------------ |
| T    | Component attribute class, which is used to distinguish different information required by different components after content areas are customized, for example, **ButtonConfiguration** for the **\<Button>** component and **CheckBoxConfiguration** of the **\<Checkbox>** component. |

**Value range of the T parameter:**

ButtonConfiguration, CheckBoxConfiguration, DataPanelConfiguration, TextClockConfiguration, ToggleConfiguration, GaugeConfiguration, LoadingProgressConfiguration, RadioConfiguration, ProgressConfiguration, RatingConfiguration, SliderConfiguration

**Supported attributes**

The universal attribute **enabled** and **contentModifier** are supported.
## CommonConfiguration\<T><sup>12+</sup>

You need a custom class to implement the **ContentModifier** API.

**Atomic service API**: This API can be used in atomic services since API version 12.

| Name | Type   | Description             |
| ------ | ------ | ---------------- |
| enabled | boolean | Whether to enable the content modifier and respond to operations such as **triggerChange**. The value **true** means to enable the content modifier and respond to operations such as **triggerChange**, and **false** means the opposite. |
| contentModifier | ContentModifier\<T> | Content modifier that sends the component information required by users to the custom content area. |


## Example
This example implements a custom check box. This check box comes in the custom pentagon style instead of the original check box style. When selected, the check box shows a red triangle pattern inside, and the title displays the word "Selected;" when deselected, the check box hides the red triangle pattern inside, and the title displays the word "Unselected."
```ts
// xxx.ets
class MyCheckboxStyle implements ContentModifier<CheckBoxConfiguration> {
  selectedColor: Color = Color.White
  constructor(selectedColor: Color) {
    this.selectedColor = selectedColor;
  }
  applyContent() : WrappedBuilder<[CheckBoxConfiguration]>
  {
    return wrapBuilder(buildCheckbox)
  }
}

@Builder function buildCheckbox(config: CheckBoxConfiguration) {
  Column({space:10}) {
      Text(config.name + (config.selected ? "(Selected)" : "(Not selected)"))
      Shape() {
        Path().width(200).height(60).commands('M100 0 L0 100 L50 200 L150 200 L200 100 Z').fillOpacity(0).strokeWidth(3)
        Path().width(10).height(10).commands('M50 0 L100 100 L0 100 Z')
          .visibility(config.selected ? Visibility.Visible : Visibility.Hidden)
          .fill(config.selected ? (config.contentModifier as MyCheckboxStyle).selectedColor : Color.Black)
          .stroke((config.contentModifier as MyCheckboxStyle).selectedColor)
          .margin({left:11,top:10})
      }
      .width(300)
      .height(200)
      .viewPort({ x: 0, y: 0, width: 310, height: 310 })
      .strokeLineJoin(LineJoinStyle.Miter)
      .strokeMiterLimit(5)
      .onClick(()=>{
            if (config.selected) {
              config.triggerChange(false)
            } else {
              config.triggerChange(true)
            }
      }).margin({left:150})
    }
  }

@Entry
@Component
struct Index {
  build() {
    Row() {
      Column() {
        Checkbox({ name: 'Check box status', group: 'checkboxGroup' })
        .select(true)
        .contentModifier(new MyCheckboxStyle(Color.Red))
        .onChange((value: boolean) => {
          console.info('Checkbox change is' + value)
        })
      }
      .width('100%')
    }
    .height('100%')
  }
}
```

![](figures/common_builder.gif)