1# @ohos.brightness (Screen Brightness) (System API)
2
3The **brightness** module provides an API for setting the screen brightness.
4
5> **NOTE**
6>
7> - 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.
8>
9> - The APIs provided by this module are system APIs.
10
11## Modules to Import
12
13```js
14import brightness from '@ohos.brightness';
15```
16
17## brightness.setValue
18
19setValue(value: number): void
20
21Sets the screen brightness.
22
23**System API**: This is a system API.
24
25**System capability**: SystemCapability.PowerManager.DisplayPowerManager
26
27**Parameters**
28
29| Name| Type  | Mandatory| Description                   |
30| ------ | ------ | ---- | ----------------------- |
31| value  | number | Yes  | Brightness value. Value range: 0 to 255. The value of this parameter must be a number.|
32
33**Error codes**
34
35For details about the error codes, see [Screen Brightness Error Codes](errorcode-brightness.md).
36
37| ID  | Error Message   |
38|---------|---------|
39| 4700101 | Failed to connect to the service. |
40| 401     | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types. |
41| 202     | Permission verification failed. A non-system application calls a system API.  |
42
43**Example:**
44
45```js
46try {
47    brightness.setValue(128);
48} catch(err) {
49    console.error('set brightness failed, err: ' + err);
50}
51```
52
53## brightness.setValue<sup>11+</sup>
54
55setValue(value: number, continuous: boolean): void
56
57Sets the screen brightness. This API is used for continuous brightness adjustment. To achieve a better performance, set **continuous** to **true** when you start, and set it to **false** after you finish.
58
59**System API**: This is a system API.
60
61**System capability**: SystemCapability.PowerManager.DisplayPowerManager
62
63**Parameters**
64
65| Name| Type  | Mandatory| Description                   |
66| ------ | ------ | ---- | ----------------------- |
67| value  | number | Yes  | Brightness value. Value range: 0 to 255. The value of this parameter must be a number.|
68| continuous  | boolean | Yes  | Whether the luminance adjustment is continuous. The value of this parameter must be of the Boolean type.|
69
70**Error codes**
71
72For details about the error codes, see [Screen Brightness Error Codes](errorcode-brightness.md).
73
74| ID  | Error Message   |
75|---------|---------|
76| 4700101 | Failed to connect to the service. |
77| 401     | Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types. |
78| 202     | Permission verification failed. A non-system application calls a system API.  |
79
80**Example:**
81
82```js
83try {
84    brightness.setValue(128, true);
85} catch(err) {
86    console.error('set brightness failed, err: ' + err);
87}
88```
89