harmony 鸿蒙@system.mediaquery (Media Query)

2022-08-09
浏览 (652)

@system.mediaquery (Media Query)

The mediaquery module provides different styles for different media types.

NOTE

The APIs of this module are no longer maintained since API version 7. You are advised to use @ohos.mediaquery instead.

The initial APIs of this module are supported since API version 3. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import mediaquery from '@system.mediaquery';

mediaquery.matchMedia

matchMedia(condition: string): MediaQueryList

Creates a MediaQueryList object based on the query condition.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
condition	string	Yes	Query condition.

Return value

Type	Description
MediaQueryList	Attributes of the MediaQueryList object created. For details, see MediaQueryList attributes.

Example

let mMediaQueryList = mediaquery.matchMedia('(max-width: 466)');

MediaQueryEvent

Defines a media query event.

System capability: SystemCapability.ArkUI.ArkUI.Full

Name	Type	Mandatory	Description
matches	boolean	Yes	Matching result.

MediaQueryList

Defines a media query list.

Attributes

System capability: SystemCapability.ArkUI.ArkUI.Full

Name	Type	Mandatory	Description
media	string	No	Serialized media query condition. This parameter is read-only.
matches	boolean	Yes	Matching result.

onchange

onchange?: (matches: boolean) => void

Called when the matches value changes.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
matches	boolean	Yes	New matches value.

MediaQueryList.addListener

addListener(callback: (event: MediaQueryEvent) => void): void

Adds a listener for this MediaQueryList object. The listener must be added before onShow is called, that is, it must be added in the onInit or onReady API.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
callback	(event: MediaQueryEvent) => void	Yes	Callback invoked when the query condition changes.

Example

import mediaquery, { MediaQueryEvent } from '@system.mediaquery';
let mMediaQueryList = mediaquery.matchMedia('(max-width: 466)');

function maxWidthMatch(e: MediaQueryEvent): void {
  if(e.matches){
    // do something
  }
}
mMediaQueryList.addListener(maxWidthMatch);

MediaQueryList.removeListener

removeListener(callback: (event: MediaQueryEvent) => void): void

Removes the listener for this MediaQueryList object.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
callback	(event: MediaQueryEvent) => void)	Yes	Callback invoked when the query condition changes.

Example

import mediaquery, { MediaQueryEvent } from '@system.mediaquery';
let mMediaQueryList = mediaquery.matchMedia('(max-width: 466)');

function maxWidthMatch(e: MediaQueryEvent): void {
  if(e.matches){
    // do something
  }
}
mMediaQueryList.removeListener(maxWidthMatch);