harmony 鸿蒙Media Query

2023-06-24
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Media Query

NOTE

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

The media attribute uses the actual size, physical pixel, and screen resolution of the device by default.

Media queries are widely used. You can use them to modify the application style based on the device type or specific features and device parameters (such as the screen resolution). Specifically, media queries allow you to design a layout style based on the device and application attributes.

CSS Syntax Rules

Use @media to import query statements. The rule is as follows:

@media [media-type] [and|or] [(media-feature)] {
  CSS-Code;
}

@media screen and (round-screen: true) { … }: The condition is met when the device screen is round.

@media (max-height: 454) { … }: Range query. CSS level 3 is used.

NOTE

The following operators are not supported: <=, >=, <, and >.

Nested parentheses are supported since API version 9.

A media query statement can contain a maximum of 512 characters.

A media query condition can contain a maximum of 32 characters.

Media Type

Type	Description
screen	Media query based on screen-related parameters.

Media Logical Operation

You can use media logical operators to implement complex media query. The following table describes the available operators.

Table 1 Media logical operators

Type	Description
and	The and operator is used to combine multiple media features into one media query, in a logical AND operation. The query is valid only when all media features are true. It can also combine media types and media functions. For example, screen and (device-type: liteWearable) and (max-height: 454) evaluates to true when the device type is wearable and the maximum height of the application is 454 pixel units.
or⁹⁺	The or operator is used to combine multiple media features into one media query, in a logical OR operation. The query is valid if a media feature is true. For example, screen and (max-height: 454) or (round-screen: true) evaluates to true when the maximum height of the application is 454 pixel units or the device screen is round.

Type

Description

and

The and operator is used to combine multiple media features into one media query, in a logical AND operation. The query is valid only when all media features are true. It can also combine media types and media functions.
For example, screen and (device-type: liteWearable) and (max-height: 454) evaluates to true when the device type is wearable and the maximum height of the application is 454 pixel units.

or⁹⁺

The or operator is used to combine multiple media features into one media query, in a logical OR operation. The query is valid if a media feature is true.
For example, screen and (max-height: 454) or (round-screen: true) evaluates to true when the maximum height of the application is 454 pixel units or the device screen is round.

Media Features

Type	Description
height	Height of the display area on the application page.
min-height	Minimum height of the display area on the application page.
max-height	Maximum height of the display area on the application page.
width	Width of the display area on the application page.
min-width	Minimum width of the display area on the application page.
max-width	Maximum width of the display area on the application page.
aspect-ratio	Ratio of the width to the height of the display area on the application page. Example: aspect-ratio: ¹⁄₂
min-aspect-ratio	Minimum ratio of the width to the height of the display area on the application page.
max-aspect-ratio	Maximum ratio of the width to the height of the display area on the application page.
round-screen	Screen type. The value true means that the screen is round, and false means the opposite.

Sample Code for the Common Media Feature

The number and type of attributes must be the same among .container blocks. Otherwise, display errors will occur.

<!-- xxx.hml -->
<div>
  <div class="container">
    <text class="title">Hello World</text>
  </div>
</div>

/* xxx.css */
.container {
  width: 300px;
  height: 600px;
  background-color: #008000;
}
.title {
    font-size: 30px;
    text-align: center;
}
@media (device-type: samrtVision) {
  .container {
    width: 500px;
    height: 500px;
    background-color: #fa8072;
  }
} 
@media (device-type: liteWearable) {
  .container {
    width: 300px;
    height: 300px;
    background-color: #008b8b;
  }
}