# Indicator

The **Indicator** component provides two types of navigation indicators: dot indicators and digit indicators.

It encapsulates the existing [indicator](ts-container-swiper.md#indicator) capabilities—previously part of the [Swiper](ts-container-swiper.md) component—and delivers them as a standalone component. You can use the **Indicator** component independently or bind it to a **Swiper** component through **IndicatorComponentController**.

When multiple **Indicator** components are bound to a single **Swiper**, only the last bound **Indicator** is active.

Conversely, if an **Indicator** is bound to multiple **Swiper** components, only the last bound **Swiper** works with the **Indicator**.

>  **NOTE**
>
> This component is supported since API version 15. Updates will be marked with a superscript to indicate their earliest API version.


## Child Components

Not supported

## APIs

IndicatorComponent(controller?: IndicatorComponentController)

A constructor used to create an **Indicator** component. You can optionally pass a controller to manage the **Indicator** component.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

|Name|Type|Mandatory|Description|
| ----- | ----- | -- |  --- |
| controller |  [IndicatorComponentController](#indicatorcomponentcontroller) | No| Controller to manage the **Indicator** component.|

## Attributes

In addition to the [universal attributes](ts-component-general-attributes.md), the following attributes are supported.

### style

style(indicatorStyle: DotIndicator | DigitIndicator)

Sets the style of the navigation indicator.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type                                                        | Mandatory| Description                                                        |
| ------ | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| indicatorStyle  | [DotIndicator](ts-container-swiper.md#dotindicator10) \| [DigitIndicator](ts-container-swiper.md#digitindicator10) | Yes  | Style of the navigation indicator.<br> \- **DotIndicator**: dot style.<br> \- **DigitIndicator**: digit style.<br>  Default style: **DotIndicator**|

> **NOTE**
>
> When **indicatorStyle** is set to **DotIndicator**, [maxDisplayCount](ts-container-swiper.md#maxdisplaycount12) does not take effect.

### count

count(totalCount: number)

Sets the total number of navigation points.

When the **Indicator** component is used with a **Swiper** component, the count is subject to the number of pages in the **Swiper** component.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type  | Mandatory| Description                                            |
| ------ | ------ | ---- | ------------------------------------------------ |
| totalCount  | number | Yes  |  Total number of navigation points.<br>Default value: **2**|

### initialIndex

initialIndex(index: number)

Sets the initial index of the navigation indicator when it first appears. If the value is less than 0 or greater than or equal to the total count, the default value **0** is used.

This attribute does not take effect when the **Indicator** component is bound to a **Swiper** component.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type  | Mandatory| Description                                            |
| ------ | ------ | ---- | ------------------------------------------------ |
| index  | number | Yes  | Initial index of the navigation indicator when it first appears.<br>Default value: **0**|

### loop

loop(isLoop: boolean)

Sets whether to enable looping.

This attribute does not take effect when the **Indicator** component is bound to a **Swiper** component.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type   | Mandatory| Description                           |
| ------ | ------- | ---- | ------------------------------- |
| isLoop  | boolean | Yes  | Whether to enable looping. The value **true** means to enable looping, and **false** means the opposite.<br>Default value: **true**|

### vertical

vertical(isVertical: boolean)

Sets whether vertical swiping is used.

This attribute does not take effect when the **Indicator** component is bound to a **Swiper** component.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type   | Mandatory| Description                              |
| ------ | ------- | ---- | ---------------------------------- |
| isVertical  | boolean | Yes  | Whether vertical swiping is used. The value **true** means vertical swiping, and **false** means horizontal swiping.<br>Default value: **false**.|

## Events

In addition to the [universal events](ts-component-general-events.md), the following events are supported.

### onChange

onChange(event: Callback\<number>)

Triggered when the currently selected navigation index changes. The callback provides the new index.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name| Type  | Mandatory| Description                |
| ------ | ------ | ---- | -------------------- |
| event  | [Callback](./ts-types.md#callback12)\<number> | Yes  | Callback triggered when the index changes.|

## IndicatorComponentController

Implements a controller for the **Indicator** component, allowing you to control navigation.

### constructor

constructor()

A constructor used to create an **IndicatorComponentController** object.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

### showNext

showNext(): void

Moves to the next navigation point.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

### showPrevious

showPrevious(): void

Moves to the previous navigation point.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

### changeIndex

changeIndex(index: number, useAnimation?: boolean): void

Moves to a specific navigation index.

**Widget capability**: This API can be used in ArkTS widgets since API version 15.

**Atomic service API**: This API can be used in atomic services since API version 15.

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

**Parameters**

| Name     | Type      | Mandatory | Description    |
| -------- | ---------- | ---- | -------- |
| index| number | Yes   | Target navigation index.|
| useAnimation| boolean | No   | Whether to use an animation for when the target index is reached. The value **true** means to use an animation, and **false** means the opposite.<br>Default value: **false**.|

## Example

### Example 1: Using a Dot Indicator with a Swiper Component
This example shows how to bind a dot-style **Indicator** component to a **Swiper** component using **IndicatorComponentController**.
```
@Entry
@Component
struct DotIndicatorDemo {
  private indicatorController: IndicatorComponentController = new IndicatorComponentController();
  private swiperController: SwiperController = new SwiperController();
  @State list: number[] = [];
  aboutToAppear(): void {
    for (let i = 1; i <= 6; i++) {
      this.list.push(i);
    }
  }

  build() {
    Column() {
      Swiper(this.swiperController) {
        ForEach(this.list, (item: string) => {
          Text(item.toString())
            .width('100%')
            .height(160)
            .backgroundColor(0xAFEEEE)
            .textAlign(TextAlign.Center)
            .fontSize(30)
        }, (item: string) => item)
      }
      .cachedCount(2)
      .index(0)
      .autoPlay(true)
      .interval(2000)
      .indicator(this.indicatorController)
      .loop(true)
      .duration(1000)
      .itemSpace(0)
      .curve(Curve.Linear)
      .onChange((index: number) => {
        console.info(index.toString());
      })

      IndicatorComponent(this.indicatorController)
        .initialIndex(0)
        .style(
          new DotIndicator()
            .itemWidth(15)
            .itemHeight(15)
            .selectedItemWidth(15)
            .selectedItemHeight(15)
            .color(Color.Gray)
            .selectedColor(Color.Blue))
        .loop(true)
        .count(6)
        .vertical(true)
        .onChange((index: number) => {
          console.log("current index: " + index );
        })
    }
  }
}
```
![bindIndicatorDotStyle](figures/bindIndicatorDotStyle.gif)

### Example 2: Using a Digit Indicator with a Swiper Component

This example shows how to bind a digit-style **Indicator** component to a **Swiper** component using **IndicatorComponentController**.

```
@Entry
@Component
struct DigitIndicatorDemo {
  private indicatorController: IndicatorComponentController = new IndicatorComponentController();
  private swiperController: SwiperController = new SwiperController();
  @State list: number[] = [];
  aboutToAppear(): void {
    for (let i = 1; i <= 6; i++) {
      this.list.push(i);
    }
  }

  build() {
    Column() {
      Swiper(this.swiperController) {
        ForEach(this.list, (item: string) => {
          Text(item.toString())
            .width('100%')
            .height(160)
            .backgroundColor(0xAFEEEE)
            .textAlign(TextAlign.Center)
            .fontSize(30)
        }, (item: string) => item)
      }
      .cachedCount(2)
      .index(0)
      .autoPlay(true)
      .interval(2000)
      .indicator(this.indicatorController)
      .loop(true)
      .duration(1000)
      .itemSpace(0)
      .curve(Curve.Linear)
      .onChange((index: number) => {
        console.info(index.toString());
      })

      IndicatorComponent(this.indicatorController)
        .initialIndex(0)
        .style(Indicator.digit()
          .fontColor(Color.Gray)
          .selectedFontColor(Color.Gray)
          .digitFont({ size: 20, weight: FontWeight.Bold })
          .selectedDigitFont({ size: 20, weight: FontWeight.Normal }))
        .loop(true)
        .count(6)
        .vertical(true)
        .onChange((index: number) => {
          console.log("current index: " + index );
        })
    }
  }
}
```

![bindIndicatorDigitStyle](figures/bindIndicatorDigitStyle.gif)