# Focus Event

A focus event is triggered when the page focus moves between components. It can be used to process related logic within the component.

>  **NOTE**
>
>  - The APIs of this module are supported since API version 8. Updates will be marked with a superscript to indicate their earliest API version.
>
>  - Currently, only the Tab button and arrow buttons on the external keyboard can be used to trigger the focus event. Sequential keyboard navigation is not supported for nested scrollable components.
>
>  - Components that have default interaction logic, such as [Button](ts-basic-components-button.md) and [TextInput](ts-basic-components-textinput.md), are focusable by default. Other components, such as [Text](ts-basic-components-text.md) and [Image](ts-basic-components-image.md), are not focusable by default. Only focusable components can trigger a focus event. To enable a component to be focusable, set its **focusable** attribute to **true**.
>  
>  - Container components that can gain focus, such as [Stack](ts-container-stack.md) and [Row](ts-container-row.md), are not focusable if they do not have any focusable child components. To make them focusable, you can add an **onClick** event or a tap gesture to the component. This makes the component implicitly focusable.
> 
>  - For details about focus development and component focusability, see [Focus Event](../../../ui/arkts-common-events-focus-event.md).

## onFocus

onFocus(event: () => void)

Triggered when the current component obtains focus.

**Atomic service API**: This API can be used in atomic services since API version 11.

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

## onBlur

onBlur(event:() => void)

Triggered when the current component loses focus.

**Atomic service API**: This API can be used in atomic services since API version 11.

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


## Example

This example demonstrates how components gain and lose focus. The colors of the buttons change when they gain or lose focus.

```ts
// xxx.ets
@Entry
@Component
struct FocusEventExample {
  @State oneButtonColor: string = '#FFC0CB'
  @State twoButtonColor: string = '#87CEFA'
  @State threeButtonColor: string = '#90EE90'

  build() {
    Column({ space: 20 }) {
      // You can use the up and down arrow keys on an external keyboard to move the focus between the three buttons. When a button gains focus, its color changes. When it loses focus, its color changes back.
      Button('First Button')
        .backgroundColor(this.oneButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.oneButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.oneButtonColor = '#FFC0CB'
        })
      Button('Second Button')
        .backgroundColor(this.twoButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.twoButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.twoButtonColor = '#87CEFA'
        })
      Button('Third Button')
        .backgroundColor(this.threeButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.threeButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.threeButtonColor = '#90EE90'
        })
    }.width('100%').margin({ top: 20 })
  }
}
```

 ![focus](figures/focus.png)