diff --git a/en/application-dev/reference/apis/js-apis-display.md b/en/application-dev/reference/apis/js-apis-display.md index ffbc73ff530a4d8f9ec39fd6e824760df9448644..aed3f0dfd30e05810bf103c4b04738ae4fe237f9 100644 --- a/en/application-dev/reference/apis/js-apis-display.md +++ b/en/application-dev/reference/apis/js-apis-display.md @@ -1,5 +1,5 @@ # 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. +The **Display** module 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** > @@ -14,11 +14,11 @@ import display from '@ohos.display'; ## DisplayState -Provides the state of a display. +Enumerates the display states. **System capability**: SystemCapability.WindowManager.WindowManager.Core -| Name| Default Value| Description| +| Name| Value| Description| | -------- | -------- | -------- | | STATE_UNKNOWN | 0 | Unknown.| | STATE_OFF | 1 | The display is shut down.| @@ -35,163 +35,169 @@ 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](#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.| +| 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](#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. +Obtains the default display object. This API uses an asynchronous callback to return the result. **System capability**: SystemCapability.WindowManager.WindowManager.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | callback | AsyncCallback<[Display](#display)> | Yes| Callback used to return the default display object.| + +| Name| Type| Mandatory| Description| +| -------- | -------- | -------- | -------- | +| callback | AsyncCallback<[Display](#display)> | Yes| Callback used to return the default display object.| **Example** - ```js - 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; - }); - ``` + +```js +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. +Obtains the default display object. This API uses a promise to return the result. **System capability**: SystemCapability.WindowManager.WindowManager.Core **Return value** - | Type | Description | - | ---------------------------------- | ---------------------------------------------- | - | Promise<[Display](#display)> | Promise used to return the default display object.| +| Type | Description | +| ---------------------------------- | ---------------------------------------------- | +| Promise<[Display](#display)> | Promise used to return the default display object.| **Example** - ```js - let promise = display.getDefaultDisplay(); - promise.then(() => { - console.log('getDefaultDisplay success'); - }).catch((err) => { - console.log('getDefaultDisplay fail: ' + JSON.stringify(err)); - }); - ``` +```js +var displayClass = null; +let promise = display.getDefaultDisplay(); +promise.then((data) => { + displayClass = data; + console.info('Succeeded in obtaining the default display object. Data:' + JSON.stringify(data)); +}).catch((err) => { + console.error('Failed to obtain the default display object. Code: ' + JSON.stringify(err)); +}); +``` ## display.getAllDisplay getAllDisplay(callback: AsyncCallback<Array<Display>>): void -Obtains all the display objects. +Obtains all display objects. This API uses an asynchronous callback to return the result. **System capability**: SystemCapability.WindowManager.WindowManager.Core **Parameters** - | Name | Type | Mandatory| Description | - | -------- | ---------------------------------------------------- | ---- | ------------------------------- | - | callback | AsyncCallback<Array<[Display](#display)>> | Yes | Callback used to return all the display objects.| +| Name | Type | Mandatory| Description | +| -------- | ---------------------------------------------------- | ---- | ------------------------------- | +| callback | AsyncCallback<Array<[Display](#display)>> | Yes | Callback used to return all the display objects.| **Example** - ```js - 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)) - }); - ``` +```js +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. +Obtains all display objects. This API uses a promise to return the result. **System capability**: SystemCapability.WindowManager.WindowManager.Core **Return value** - | Type | Description | - | ----------------------------------------------- | ------------------------------------------------------- | - | Promise<Array<[Display](#display)>> | Promise used to return all the display objects.| +| Type | Description | +| ----------------------------------------------- | ------------------------------------------------------- | +| Promise<Array<[Display](#display)>> | Promise used to return all the display objects.| **Example** - ```js - let promise = display.getAllDisplay(); - promise.then(() => { - console.log('getAllDisplay success'); - }).catch((err) => { - console.log('getAllDisplay fail: ' + JSON.stringify(err)); - }); - ``` +```js +let promise = display.getAllDisplay(); +promise.then((data) => { + console.info('Succeeded in obtaining all the display objects. Data: ' + JSON.stringify(data)); +}).catch((err) => { + console.error('Failed to obtain all the display objects. Code: ' + JSON.stringify(err)); +}); +``` ## display.on('add'|'remove'|'change') on(type: 'add'|'remove'|'change', callback: Callback<number>): void -Enables listening. +Subscribes to display changes. **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.| + +| Name| Type| Mandatory| Description| +| -------- | -------- | -------- | -------- | +| type | string | Yes| Event type.
- **add**, indicating the display addition event.
- **remove**, indicating the display removal event.
- **change**, indicating the display change event.| +| callback | Callback<number> | Yes| Callback used to return the ID of the display.| **Example** - ```js - var callback = (data) => { - console.info('Listening enabled. Data: ' + JSON.stringify(data)) - } - display.on("add", callback); - ``` +```js +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. +Unsubscribes from display changes. **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.| + +| Name| Type| Mandatory| Description| +| -------- | -------- | -------- | -------- | +| type | string | Yes| Event type.
- **add**, indicating the display addition event.
- **remove**, indicating the display removal event.
- **change**, indicating the display change event.| +| callback | Callback<number> | No| Callback used to return the ID of the display.| **Example** - ```js - display.off("remove"); - ``` +```js +display.off("remove"); +```