## How do I determine whether an application is a system application?
Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)
**Solution**
Use **bundleManager.getApplicationInfo** (available only for system applications) to obtain application information, and check the value of **systemApp** in the information. The application is a system application if the value is **true**.
## How do I obtain the version code and version name of an application?
Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)
**Solution**
Use **bundleManager.getBundleInfoForSelf\(\)** to obtain the bundle information, which contains the version code (specified by **BundleInfo.versionCode**) and version name (specified by **BundleInfo.versionName**) .
**Example**
```
import bundleManager from '@ohos.bundle.bundleManager';
import hilog from '@ohos.hilog';
let bundleFlags = bundleManager.BundleFlag.GET_BUNDLE_INFO_DEFAULT;
[UIAbilityContext](../reference/apis/js-apis-inner-application-uiAbilityContext.md#uiabilitycontext) and [AbilityInfo](../reference/apis/js-apis-bundleManager-abilityInfo.md#abilityinfo)
## How do I obtain the application version number, version name, and screen resolution?
Applicable to: OpenHarmony 3.2 Beta5
**Solution**
1. Obtain the bundle information from the **@ohos.bundle.bundleManager** module.
The bundle information contains the application version number and version name.
```
import bundleManager from '@ohos.bundle.bundleManager';
## Can I obtain the HAP information of other applications from the current application?
Applicable to: OpenHarmony 3.2 Beta (API version 9)
According to the OpenHarmony security design specifications, the SDK does not provide APIs for third-party applications to obtain bundle information (including but not limited to the application name and version number) of other applications.
## How do I determine whether an application is a system application?
Applicable to: OpenHarmony SDK 3.2.5.5, stage model of API version 9
Use **bundle.getApplicationInfo** to obtain the application information, and then check the value of **systemApp** in the information. The application is a system application if the value is **true**.
## Why do the isStatusBarLightIcon and isNavigationBarLightIcon attributes not take effect when window.setSystemBarProperties() is called?
## How do I obtain the DPI of a device?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Applicable to: OpenHarmony 3.2 Beta5 (API version 9, stage model)
In effect, the **isStatusBarLightIcon** and **isNavigationBarLightIcon** attributes turn the font white when set to **true**. If **statusBarContentColor** is also set in **window.setSystemBarProperties()**, the **isStatusBarLightIcon** attribute does not take effect. Similarly, if **navigationBarContentColor** is set, the **isNavigationBarLightIcon** attribute does not take effect.
**Solution**
## How do I set the style of the system bar?
Import the **@ohos.display** module and call the **getDefaultDisplaySync\(\)** API.
Applicable to: OpenHarmony SDK 3.2.3.5, stage model of API version 9
**Example**
Import the **\@ohos.window** module, and call **window.setSystemBarProperties()**.
console.error('Failed to enable the full-screen mode. Cause:' + JSON.stringify(err));
return;
}
console.info('Succeeded in enabling the full-screen mode. Data: ' + JSON.stringify(data));
});
```
## How do I obtain the window width and height?
Applicable to: OpenHarmony SDK 3.2.3.5, stage model of API version 9
Applicable to: OpenHarmony SDK 3.2 Beta5 (API version 9, stage model)
Use **window.getProperties()** to obtain the window properties. The **windowRect** field in the properties specifies the window width and height.
**Solution**
Example:
Import the **@ohos.window** module, obtain a **Window** object, and use **getWindowProperties\(\)** of the object to obtain the window properties. The **windowRect** field in the properties specifies the window width and height.
**Example**
```ts
letpromise=windowClass.getProperties();
promise.then((data)=>{
console.info('Succeeded in obtaining the window properties. Data: '+JSON.stringify(data.windowRect));
}).catch((err)=>{
console.error('Failed to obtain the window properties. Cause: '+JSON.stringify(err));
});
```
## How do I set the color of the system bar?
Applicable to: OpenHarmony SDK 3.2.5.5, stage model of API version 9
## How do I obtain the frame data of a camera when using the XComponent to display the preview output stream of the camera?
Applicable to: OpenHarmony 3.2 (API version 9, stage model)
**Symptom**
Currently, the API does not support real-time preview of the camera frame data. To obtain the frame data, you must bind an action, for example, photographing.
**Solution**
Create a dual-channel preview to obtain the frame data.
## How do I obtain the preview image of the front camera?
Applicable to: OpenHarmony 3.2 (API version 9, stage model)
**Solution**
1. Use the **@ohos.multimedia.camera** module to obtain the physical camera information.
```
let cameraManager = await camera.getCameraManager(context);
let camerasInfo = await cameraManager.getSupportedCameras();
let cameraDevice = this.camerasInfo[0];
```
2. Create and start the input stream channel of the physical camera.
```
let cameraInput = await cameraManager.createCameraInput(cameraDevice);
await this.cameraInput.open();
```
3. Obtain the output formats supported by the camera, and create a preview output channel based on the surface ID provided by the XComponent.
```
let outputCapability = await this.cameraManager.getSupportedOutputCapability(cameraDevice);
let previewProfile = this.outputCapability.previewProfiles[0];
let previewOutput = await cameraManager.createPreviewOutput(previewProfile, previewId);
```
4. Create a camera session, add the camera input stream and preview output stream to the session, and start the session. The preview image is displayed on the XComponent.
```
let captureSession = await cameraManager.createCaptureSession();
await captureSession.beginConfig();
await captureSession.addInput(cameraInput);
await captureSession.addOutput(previewOutput);
await this.captureSession.commitConfig()
await this.captureSession.start();
```
## How do I set the camera focal length?
Applicable to: OpenHarmony 3.2 (API version 9, stage model)
**Solution**
1. Check whether the camera is a front camera. A front camera does not support focal length setting.
2. Use **captureSession.getZoomRatioRange\(\)** to obtain the focal length range supported by the device.
3. Check whether the target focal length is within the range obtained. If yes, call **captureSession.setZoomRatio\(\)** to set the focal length.
## How do I play music in the background?
Applicable to: OpenHarmony 3.2 (API version 9, stage model)
**Symptom**
Music cannot be played in the background.
**Solution**
**AVSession** controls media playback. When a third-party application switches to the background or encounters a screen lock event, media playback is forcibly paused and the application is unaware of the pause. To enable the application to continue the playback in the background, request a continuous task and access the AVSession capability, which allows Control Panel to control the playback behavior of third-party applications.
## Are the APIs used for obtaining PPG and ECG sensor data open to individual developers?
Applicable to: OpenHarmony 3.1 Beta 5 (API version 9)
Data collected by the PPG and ECG sensors of wearable devices is personal privacy data. Therefore, relative APIs are not open to individual developers.
## What does the following error message mean: "Stage model module... does not support including OpenHarmony npm packages or modules in FA model. OpenHarmony build tasks will not be executed, and OpenHarmony resources will not be packed."
## How do I obtain available third-party libraries?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Applicable to: OpenHarmony 3.1 Beta 5 (API version 9)
The third- and fourth-party libraries are not yet compatible with the stage model of API version 9 and cannot be used.
The three-party and four-party libraries that can be obtained through ohpm are summarized in the [OpenHarmony-TPC/tpc_resource repository](https://gitee.com/openharmony-tpc/tpc_resource). You can access this repository, and find the desired component based on the directory index.
## Can I transfer project-level dependencies?
## Which third-party libraries are related to network requests?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Applicable to: OpenHarmony 3.1 Beta 5 (API version 9)
For example, if project A depends on project B and project B depends on project C, can project A directly use the APIs provided by project C?
The following third-party libraries are related to network requests: [Axios](https://gitee.com/openharmony-sig/axios), httpclient, and okdownload. For details, see the [OpenHarmony-TPC/tpc_resource repository](https://gitee.com/openharmony-tpc/tpc_resource).
No. Project A cannot directly use the APIs provided by project C. The project packing tool NPM does not support dependency transfer. To use the APIs provided by project C, you can add the dependency of project C to project A.
## How do I use ohpm to import third- and fourth-party libraries?
## How do I obtain available third-party libraries?
Applicable to: OpenHarmony 3.1 Beta 5 (API version 9)
Applicable to: OpenHarmony SDK 3.2.6.5, stage model of API version 9
**Solution**
For details, see [Third-Party Components That Can Be Directly Used on OpenHarmony](https://gitee.com/openharmony-sig/third_party_app_libs).
- Method 1:
1. Open the **Terminal** window and run the following command to go to the **entry** directory:
## Which third-party libraries are related to network requests?
```
cd entry
```
2. Run the following command to install a third-party library, for example, **dayjs**:
```
ohpm install dayjs
```
3. Add the following statement in the .js file to import the third-party library:
```
import dayjs from 'dayjs';
```
Applicable to: OpenHarmony SDK 3.2.6.5, stage model of API version 9
The [Axios](https://gitee.com/openharmony-sig/axios) library is related to network requests.
## How do I use NPM to import third- and fourth-party libraries?
Applicable to: OpenHarmony SDK 3.2.5.5, stage model of API version 9
- Method 1:
1. Open the **Terminal** window and run the following command to go to the **entry** directory:
```
cd entry
```
2. Run the following command to install a third-party package, for example, **dayjs**:
```
npm install dayjs --save
```
3. Add the following statement in the .js file to import the package:
```
import dayjs from 'dayjs';
```
- Method 2:
1. Enter the **entry** directory of the project and open the **package.json** file.
2. Write the third-party NPM package to be installed (for example, **dayjs**) in the **package.json** file.
```
{
"dependencies": {
"dayjs": "^1.10.4",
- Method 2:
1. Enter the **entry** directory of the project and open the **oh-package.json5** file.
2. Write the third-party library to be installed (for example, **dayjs**) in the **oh-package.json5** file.
```
{
"dependencies": {
"dayjs": "^1.10.4",
}
}
}
```
3. Open the **Terminal** window and run the following command to go to the **entry** directory:
```
cd entry
```
4. Run the following command to install NPM:
```
npm install
```
5. Add the following statement in the .js file to import the package:
```
import dayjs from 'dayjs';
```
```
3. Open the **Terminal** window and run the following command to go to the **entry** directory:
```
cd entry
```
4. Run the following command to install the third-party library:
```
ohpm install
```
5. Add the following statement in the .js file to import the third-party library:
letavoidAreaRect=data.regionTint[0].region;// data.regionTint is an array that contains the rectangle coordinates of the status bar and navigation bar.
