Display
Provides APIs for managing displays, such as obtaining information about the default display, obtaining information about all displays, and listening for the addition and removal of displays.
NOTE
The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
Modules to Import
import display from '@ohos.display';
DisplayState
Provides the state of a display.
System capability: SystemCapability.WindowManager.WindowManager.Core
Name | Default Value | Description |
---|---|---|
STATE_UNKNOWN | 0 | Unknown. |
STATE_OFF | 1 | The display is shut down. |
STATE_ON | 2 | The display is powered on. |
STATE_DOZE | 3 | The display is in sleep mode. |
STATE_DOZE_SUSPEND | 4 | The display is in sleep mode, and the CPU is suspended. |
STATE_VR | 5 | The display is in VR mode. |
STATE_ON_SUSPEND | 6 | The display is powered on, and the CPU is suspended. |
Display
Describes the attributes of a display.
System capability: SystemCapability.WindowManager.WindowManager.Core
Name | Type | Readable | Writable | Description |
---|---|---|---|---|
id | number | Yes | No | ID of the display. |
name | string | Yes | No | Name of the display. |
alive | boolean | Yes | No | Whether the display is alive. |
state | DisplayState | Yes | No | State of the display. |
refreshRate | number | Yes | No | Refresh rate of the display. |
rotation | number | Yes | No | Screen rotation angle of the display. |
width | number | Yes | No | Width of the display, in pixels. |
height | number | Yes | No | Height of the display, in pixels. |
densityDPI | number | Yes | No | Screen density of the display, in DPI. |
densityPixels | number | Yes | No | Screen density of the display, in pixels. |
scaledDensity | number | Yes | No | Scaling factor for fonts displayed on the display. |
xDPI | number | Yes | No | Exact physical dots per inch of the screen in the horizontal direction. |
yDPI | number | Yes | No | Exact physical dots per inch of the screen in the vertical direction. |
display.getDefaultDisplay
getDefaultDisplay(callback: AsyncCallback<Display>): void
Obtains the default display object.
System capability: SystemCapability.WindowManager.WindowManager.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
callback | AsyncCallback<Display> | Yes | Callback used to return the default display object. |
Example
var displayClass = null;
display.getDefaultDisplay((err, data) => {
if (err.code) {
console.error('Failed to obtain the default display object. Code: ' + JSON.stringify(err));
return;
}
console.info('Succeeded in obtaining the default display object. Data:' + JSON.stringify(data));
displayClass = data;
});
display.getDefaultDisplay
getDefaultDisplay(): Promise<Display>
Obtains the default display object.
System capability: SystemCapability.WindowManager.WindowManager.Core
Return value
Type | Description |
---|---|
Promise<Display> | Promise used to return the default display object. |
Example
let promise = display.getDefaultDisplay();
promise.then(() => {
console.log('getDefaultDisplay success');
}).catch((err) => {
console.log('getDefaultDisplay fail: ' + JSON.stringify(err));
});
display.getAllDisplay
getAllDisplay(callback: AsyncCallback<Array<Display>>): void
Obtains all the display objects.
System capability: SystemCapability.WindowManager.WindowManager.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
callback | AsyncCallback<Array<Display>> | Yes | Callback used to return all the display objects. |
Example
display.getAllDisplay((err, data) => {
if (err.code) {
console.error('Failed to obtain all the display objects. Code: ' + JSON.stringify(err));
return;
}
console.info('Succeeded in obtaining all the display objects. Data: ' + JSON.stringify(data))
});
display.getAllDisplay
getAllDisplay(): Promise<Array<Display>>
Obtains all the display objects.
System capability: SystemCapability.WindowManager.WindowManager.Core
Return value
Type | Description |
---|---|
Promise<Array<Display>> | Promise used to return all the display objects. |
Example
let promise = display.getAllDisplay();
promise.then(() => {
console.log('getAllDisplay success');
}).catch((err) => {
console.log('getAllDisplay fail: ' + JSON.stringify(err));
});
display.on('add'|'remove'|'change')
on(type: 'add'|'remove'|'change', callback: Callback<number>): void
Enables listening.
System capability: SystemCapability.WindowManager.WindowManager.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
type | string | Yes | Listening type. The available values are as follows: - add: listening for whether a display is added - remove: listening for whether a display is removed - change: listening for whether a display is changed |
callback | Callback<number> | Yes | Callback used to return the ID of the display. |
Example
var callback = (data) => {
console.info('Listening enabled. Data: ' + JSON.stringify(data))
}
display.on("add", callback);
display.off('add'|'remove'|'change')
off(type: 'add'|'remove'|'change', callback?: Callback<number>): void
Disables listening.
System capability: SystemCapability.WindowManager.WindowManager.Core
Parameters
Name | Type | Mandatory | Description |
---|---|---|---|
type | string | Yes | Listening type. The available values are as follows: - add: listening for whether a display is added - remove: listening for whether a display is removed - change: listening for whether a display is changed |
callback | Callback<number> | No | Callback used to return the ID of the display. |
Example
display.off("remove");