harmony 鸿蒙@ohos.arkui.inspector (Layout Callback)

2023-10-30
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@ohos.arkui.inspector (Layout Callback)

The Inspector module provides APIs for registering the component layout and drawing completion callbacks.

NOTE

The APIs of this module are supported since API version 10. Updates will be marked with a superscript to indicate their earliest API version.

Since API version 10, you can use the getUIInspector API in UIContext to obtain the UIInspector object associated with the current UI context.

Modules to Import

import inspector from '@ohos.arkui.inspector'

inspector.createComponentObserver

createComponentObserver(id: string): ComponentObserver

Creates an observer for the specified component.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
id	string	Yes	Component ID.

Return value

Type	Description
ComponentObserver	Component observer, which is used to register and unregister listeners.

Example

let listener:inspector = inspector.createComponentObserver('COMPONENT_ID'); // Listen for callback events of the component whose ID is COMPONENT_ID.

ComponentObserver

Implements a component observer for completion of component layout and drawing, including the first query result when the observer is requested.

on

on(type: ‘layout’, callback: () => void): void

Registers a listener for completion of component layout.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the listener. The value must be ‘layout’ or ‘draw’. ‘layout’: completion of component layout. ‘draw’: completion of component drawing.
callback	void	Yes	Callback invoked upon completion of component layout or drawing.

off

off(type: ‘layout’, callback?: () => void): void

Unregisters the listener for completion of component layout.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the listener. The value must be ‘layout’ or ‘draw’. ‘layout’: completion of component layout. ‘draw’: completion of component drawing.
callback	void	No	Callback to unregister. If this parameter is not specified, all callbacks of the specified type are unregistered.

on

on(type: ‘draw’, callback: () => void): void

Registers a listener for completion of component drawing.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the listener. The value must be ‘layout’ or ‘draw’. ‘layout’: completion of component layout. ‘draw’: completion of component drawing.
callback	void	Yes	Callback invoked upon completion of component layout or drawing.

off

off(type: ‘draw’, callback?: () => void): void

Unregisters the listener for completion of component drawing.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the listener. The value must be ‘layout’ or ‘draw’. ‘layout’: completion of component layout. ‘draw’: completion of component drawing.
callback	void	No	Callback to unregister. If this parameter is not specified, all callbacks of the specified type are unregistered.

Example

  import inspector from '@ohos.arkui.inspector'

  @Entry
  @Component
  struct ImageExample {
    build() {
      Column() {
        Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Start }) {
          Row({ space: 5 }) {
            Image($r('app.media.app_icon'))
              .width(110)
              .height(110)
              .border({ width: 1 })
              .id('IMAGE_ID')
          }
        }
      }.height(320).width(360).padding({ right: 10, top: 10 })
    }

    listener:inspector.ComponentObserver = inspector.createComponentObserver('IMAGE_ID')

    aboutToAppear() {
      let onLayoutComplete:()=>void=():void=>{
          // do something here
      }
      let onDrawComplete:()=>void=():void=>{
          // do something here
      }
      let FuncLayout = onLayoutComplete // bind current js instance
      let FuncDraw = onDrawComplete // bind current js instance

      this.listener.on('layout', FuncLayout)
      this.listener.on('draw', FuncDraw)
    }
  }