harmony 鸿蒙XComponent

2022-08-09
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XComponent

The <XComponent> can accept and display the EGL/OpenGL ES and media data input.

NOTE

This component is supported since API version 8. Updates will be marked with a superscript to indicate their earliest API version.

Child Components

Child components are not supported when type is set to “surface”.

Since API version 9, child components are supported when type is set to “component”.

APIs

XComponent

XComponent(value: {id: string, type: string, libraryname?: string, controller?: XComponentController})

Parameters

Name	Type	Mandatory	Description
id	string	Yes	Unique ID of the component. The value can contain a maximum of 128 characters.
type	string	Yes	Type of the component. The options are as follows: - “surface”: The custom content is displayed individually on the screen. This option is used for displaying EGL/OpenGL ES and media data. - “component”⁹⁺: The component becomes a container where non-UI logic can be executed to dynamically load the display content. Any other value evaluates to “surface”.
libraryname	string	No	Name of the dynamic library generated after compilation at the application native layer. This parameter is valid only when type is “surface”.
controller	XComponentcontroller	No	Controller bound to the component, which can be used to invoke methods of the component. This parameter is valid only when the component type is “surface”.

XComponent¹⁰⁺

XComponent(value: {id: string, type: XComponentType, libraryname?: string, controller?: XComponentController})

Parameters

Name	Type	Mandatory	Description
id	string	Yes	Unique ID of the component. The value can contain a maximum of 128 characters.
type	XComponentType	Yes	Type of the component.
libraryname	string	No	Name of the dynamic library generated after compilation at the application native layer. This parameter is valid only when type is SURFACE or TEXTURE.
controller	XComponentcontroller	No	Controller bound to the component, which can be used to invoke methods of the component. This parameter is valid only when type is SURFACE or TEXTURE.

XComponentType¹⁰⁺

Name	Description
SURFACE	The custom content is displayed individually on the screen. This option is used for displaying EGL/OpenGL ES and media data.
COMPONENT	The component becomes a container where non-UI logic can be executed to dynamically load the display content.
TEXTURE	The custom content of the component is grouped and displayed together with content of the component.

NOTE

When type is set to COMPONENT(“component”), the <XComponent> functions as a container, where child components are laid out vertically.

Vertical alignment: FlexAlign.Start

Horizontal alignment: FlexAlign.Center

The component does not respond to any events.

Layout changes and event responses can be set by mounting child components.

The non-UI logic written internally needs to be encapsulated in one or more functions.

Attributes

You can customize the content displayed in the <XComponent>. Depending on the type settings, the support for the universal attributes background, opacity, and image effects varies.
When type is set to SURFACE(“surface”), only the shadow attribute of image effects. For configuration of other attributes, you are advised to use the APIs provided by EGL/OpenGL ES instead.
When type is set to COMPONENT(“component”), only the shadow attribute of image effects. For configuration of other attributes, you are advised to mount child components.
When type is set to TEXTURE, only the backgroundColor attribute of background, the shadow attribute of image effects, and opacity are supported. For configuration of other attributes, you are advised to use the APIs provided by EGL/OpenGL ES instead.

Events

When type is set to SURFACE(“surface”) or TEXTURE, the following events are supported. The universal events are not supported.

onLoad

onLoad(callback: (event?: object) => void )

Triggered when the plug-in is loaded.

Parameters

Name	Type	Mandatory	Description
event	object	No	Context of the <XComponent> object. The APIs contained in the context are defined at the C++ layer by developers.

onDestroy

onDestroy(event: () => void )

Triggered when the plug-in is destroyed.

XComponentController

Defines the controller of the <XComponent>. You can bind the controller to the <XComponent> to invoke the methods of the component through the controller.

Creating an Object

xcomponentController: XComponentController = new XComponentController()

getXComponentSurfaceId

getXComponentSurfaceId(): string

Obtains the ID of the surface held by the <XComponent>, which can then be used for @ohos APIs. For details, see Camera Management. This API works only when type of the <XComponent> is set to SURFACE(“surface”) or TEXTURE.

Return value

Type	Description
string	ID of the surface held by the <XComponent>.

setXComponentSurfaceSize

setXComponentSurfaceSize(value: {surfaceWidth: number, surfaceHeight: number}): void

Sets the width and height of the surface held by the <XComponent>. This API works only when type of the <XComponent> is set to SURFACE(“surface”) or TEXTURE.

Parameters

Name	Type	Mandatory	Description
surfaceWidth	number	Yes	Width of the surface held by the <XComponent>.
surfaceHeight	number	Yes	Height of the surface held by the <XComponent>.

getXComponentContext

getXComponentContext(): Object

Obtains the context of an <XComponent> object. This API works only when type of the <XComponent> is set to SURFACE(“surface”) or TEXTURE.

Return value

Type	Description
Object	Context of the <XComponent> object. The APIs contained in the context are defined by developers.

Example

You can preview how this component looks on a real device. The preview is not yet available in the DevEco Studio Previewer.

// xxx.ets
@Entry
@Component
struct PreviewArea {
  private surfaceId : string =''
  xcomponentController: XComponentController = new XComponentController()
  build() {
    Row() {
      XComponent({
        id: 'xcomponent',
        type: 'surface',
        controller: this.xcomponentController
      })
        .onLoad(() => {
          this.xcomponentController.setXComponentSurfaceSize({surfaceWidth:1920,surfaceHeight:1080});
          this.surfaceId = this.xcomponentController.getXComponentSurfaceId()
        })
        .width('640px')
        .height('480px')
    }
    .backgroundColor(Color.Black)
    .position({x: 0, y: 48})
  }
}