If a service needs to be continued when the application or service module is running in the background (not visible to users), the application or service module can request a transient task or continuous task for delayed suspension based on the service type.
| function requestSuspendDelay(reason: string, callback: Callback<void>): **DelaySuspendInfo**; | Requests delayed suspension after the application switches to the background.<br>The default duration of delayed suspension is 180000 when the battery level is higher than or equal to the broadcast low battery level and 60000 when the battery level is lower than the broadcast low battery level.|
| function getRemainingDelayTime(requestId: number, callback: AsyncCallback<number>): void;<br>function getRemainingDelayTime(requestId: number): Promise<number>; | Obtains the remaining duration before the application is suspended. (The value of **requestId** is obtained from the return value of **requestSuspendDelay**.)<br>Two asynchronous methods are provided: callback and promise.|
| function cancelSuspendDelay(requestId: number): void; | Cancels the suspension delay. (The value of **requestId** is obtained from the return value of **requestSuspendDelay**.)|
**Table 2** Parameters in DelaySuspendInfo
| requestSuspendDelay(reason: string, callback: Callback<void>): [DelaySuspendInfo](../reference/apis/js-apis-backgroundTaskManager.md#delaysuspendinfo) | Requests delayed suspension after the application switches to the background.<br>The default duration value of delayed suspension is 180000 milliseconds when the battery level is normal and 60000 milliseconds when the battery level is low. |
| getRemainingDelayTime(requestId: number): Promise<number> | Obtains the remaining duration before the application is suspended.<br>This API uses a promise to return the task execution result.|
| cancelSuspendDelay(requestId: number): void | Cancels the suspension delay.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| requestId | number | Yes| ID of the suspension delay request.|
| actualDelayTime | number | Yes| Actual suspension delay duration of the application, in milliseconds.|
## How to Develop
### How to Develop
1. Request a suspension delay.
...
...
@@ -65,7 +53,7 @@ import backgroundTaskManager from '@ohos.backgroundTaskManager';
| function startBackgroundRunning(context: Context, bgMode: BackgroundMode, wantAgent: WantAgent, callback: AsyncCallback<void>): void;<br>function startBackgroundRunning(context: Context, bgMode: BackgroundMode, wantAgent: WantAgent): Promise<void>; | Requests a continuous task from the system so that the application keeps running in the background.|
| function stopBackgroundRunning(context: Context, callback: AsyncCallback<void>): void;<br>function stopBackgroundRunning(context: Context): Promise<void>; | Cancels the continuous task.|
| startBackgroundRunning(context: Context, bgMode: BackgroundMode, wantAgent: WantAgent): Promise<void> | Requests a continuous task from the system so that the application keeps running in the background.|
| stopBackgroundRunning(context: Context): Promise<void> | Cancels the continuous task.|
For details about **wantAgent**, see [WantAgent](../reference/apis/js-apis-wantAgent.md).
**Table 4** Background modes
**Table 3** Background modes
| Name| ID| Description| Item|
| -------- | -------- | -------- | -------- |
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@@ -124,39 +114,30 @@ For details about **wantAgent**, see [WantAgent](../reference/apis/js-apis-wantA
1. Create an API version 8 project. Then right-click the project directory and choose **New > Ability > Service Ability** to create a Service ability. Configure the continuous task permission and background mode type in the **config.json** file, with the ability type set to **service**.
@@ -201,13 +182,11 @@ For details about **wantAgent**, see [WantAgent](../reference/apis/js-apis-wantA
```
## Development Examples
### Development Examples
For details about how to use the Service ability in the FA model, see [Service Ability Development](../ability/fa-serviceability.md).
If an application does not need to interact with a continuous task in the background, you can use **startAbility()** to start the Service ability. In the **onStart** callback of the Service ability, call **startBackgroundRunning()** to declare that the Service ability needs to run in the background for a long time. After the task execution is complete, call **stopBackgroundRunning()** to release resources.
After a service is started, call the API for requesting a continuous task in the **onStart** callback of the Service ability to declare that the service needs to run in the background for a long time. In the **onStop** callback, call the API for canceling the continuous task.
If an application needs to interact with a continuous task in the background (for example, an application related to music playback), you can use **connectAbility()** to start and connect to the Service ability. After obtaining the proxy of the Service ability, the application can communicate with the Service ability and control the request and cancellation of continuous tasks.
```js
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@@ -289,7 +268,6 @@ export default {
},
onStop(){
console.info('ServiceAbility onStop');
stopBackgroundRunning();
},
onConnect(want){
console.info('ServiceAbility onConnect');
...
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@@ -306,3 +284,9 @@ export default {
}
};
```
## Samples
The following sample is provided to help you better understand how to develop background task management:
-[`BackgroundTaskManager`: Background Task Management (eTS, API version 8)](https://gitee.com/openharmony/app_samples/tree/master/ResourcesSchedule/BackgroundTaskManager)
