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Signed-off-by: Nwusongqing <wusongqing@huawei.com>
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en/application-dev/ability/fa-serviceability.md
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......@@ -5,22 +5,20 @@ A Service ability is used to run tasks in the background, such as playing music
## Available APIs
**Table 1** Service ability lifecycle callbacks
**Table 1** Service ability lifecycle APIs
|API|Description|
|:------|:------|
|onStart|Called to initialize a Service ability when the Service ability is being created. This callback is invoked only once in the entire lifecycle of a Service ability. The **Want** object passed to this callback must be null.|
|onCommand|Called every time a Service ability is created on a client. You can calculate calling statistics and perform initialization operations in this callback.|
|onConnect|Called when another ability is connected to the Service ability.|
|onDisconnect|Called when another ability is disconnected from the Service ability.|
|onStop|Called when the Service ability is being destroyed. You should override this callback for your Service ability to clear its resources, such as threads and registered listeners.|
|onStart?(): void|Called to initialize a Service ability being created. This callback is invoked only once in the entire lifecycle of a Service ability. The **Want** object passed to this callback must be null.|
|onCommand?(want: Want, startId: number): void|Called every time a Service ability is created on a client. You can collect calling statistics and perform initialization operations in this callback.|
|onConnect?(want: Want): rpc.RemoteObject|Called when another ability is connected to the Service ability.|
|onDisconnect?(want: Want): void|Called when another ability is disconnected from the Service ability.|
|onStop?(): void|Called when the Service ability is being destroyed. You should override this callback for your Service ability to clear its resources, such as threads and registered listeners.|
## How to Develop
### Creating a Service Ability
### Creating and Registering a Service Ability
1. Create a child class of the **Ability** class and override the following Service ability-related lifecycle callbacks to implement your own logic for processing requests to interact with your Service ability:
The following code snippet shows how to create a Service ability:
1. Override the Service ability-related lifecycle callbacks to implement your own logic for processing interaction requests.
```javascript
export default {
......@@ -32,6 +30,7 @@ A Service ability is used to run tasks in the background, such as playing music
},
onConnect(want) {
console.log('ServiceAbility OnConnect');
return null;
},
onDisconnect(want) {
console.log('ServiceAbility OnDisConnect');
......@@ -44,7 +43,7 @@ A Service ability is used to run tasks in the background, such as playing music
2. Register a Service ability.
You must declare your Service ability in the **config.json** file by setting its **type** attribute to **service**.
Declare the Service ability in the **config.json** file by setting its **type** attribute to **service**.
```javascript
{
......@@ -78,12 +77,12 @@ The following code snippet shows how to start a Service ability running on the l
```javascript
import featureAbility from '@ohos.ability.featureAbility';
let promise = await featureAbility.startAbility(
let promise = featureAbility.startAbility(
{
want:
{
bundleName: "com.jstest.serviceability",
abilityName: "com.jstest.serviceability.MainAbility",
bundleName: "com.jstest.service",
abilityName: "com.jstest.service.ServiceAbility",
},
}
);
......@@ -93,11 +92,26 @@ After the preceding code is executed, the **startAbility()** API is called to st
- If the Service ability is not running, the system calls **onStart()** to initialize the Service ability, and then calls **onCommand()** on the Service ability.
- If the Service ability is running, the system directly calls **onCommand()** on the Service ability.
The following code snippet shows how to start a Service ability running on the remote device. For details about **getRemoteDeviceId()**, see [Connecting to a Remote Service Ability](#connecting-to-a-remote-service-ability-applying-only-to-system-applications).
```javascript
import featureAbility from '@ohos.ability.featureAbility';
let promise = featureAbility.startAbility(
{
want:
{
deviceId: getRemoteDeviceId(), // Remote device ID
bundleName: "com.jstest.service",
abilityName: "com.jstest.service.ServiceAbility",
},
}
);
```
### Stopping a Service Ability
Once created, the Service ability keeps running in the background. The system does not stop or destroy it unless memory resources must be reclaimed. You can call **terminateSelf()** on a Service ability to stop it.
Once created, the Service ability keeps running in the background. The system does not stop or destroy it unless memory resources must be reclaimed.
......@@ -105,13 +119,24 @@ After the preceding code is executed, the **startAbility()** API is called to st
If you need to connect a Service ability to a Page ability or to a Service ability in another application, you must first implement the **IAbilityConnection** API for the connection. A Service ability allows other abilities to connect to it through **connectAbility()**.
When calling **connectAbility()**, you should pass a **Want** object containing information about the target Service ability and an **IAbilityConnection** object to the API. **IAbilityConnection** provides the following callbacks that you should implement: **onConnect()**, **onDisconnect()**, and **onFailed()**. The **onConnect()** callback is invoked when a Service ability is connected, **onDisconnect()** is invoked when a Service ability is unexpectedly disconnected, and **onFailed()** is invoked when a connection to a Service ability fails.
The following code snippet shows how to implement the callbacks:
You can use either of the following methods to connect to a Service ability:
```javascript
let mRemote;
function onConnectCallback(element, remote){
1. Using the IDL to automatically generate code
Use OpenHarmony Interface Definition Language (IDL) to automatically generate the corresponding client, server, and **IRemoteObject** code. For details, see [“Development Using TS” in OpenHarmony IDL Specifications and User Guide](https://gitee.com/openharmony/docs/blob/master/en/application-dev/IDL/idl-guidelines.md#development-using-ts).
2. Writing code in the corresponding file
When calling **connectAbility()**, you should pass a **Want** object containing information about the target Service ability and an **IAbilityConnection** object to the API. **IAbilityConnection** provides the following callbacks that you should implement: **onConnect()**, **onDisconnect()**, and **onFailed()**. The **onConnect()** callback is invoked when a Service ability is connected, **onDisconnect()** is invoked when a Service ability is unexpectedly disconnected, and **onFailed()** is invoked when a connection to a Service ability fails.
The following code snippet shows how to implement the callbacks:
```javascript
import prompt from '@system.prompt'
let mRemote;
function onConnectCallback(element, remote){
console.log('onConnectLocalService onConnectDone element: ' + element);
console.log('onConnectLocalService onConnectDone remote: ' + remote);
mRemote = remote;
......@@ -137,43 +162,43 @@ function onConnectCallback(element, remote){
console.log('sendRequest error:' + e);
});
}
}
function onDisconnectCallback(element){
function onDisconnectCallback(element){
console.log('ConnectAbility onDisconnect Callback')
}
}
function onFailedCallback(code){
function onFailedCallback(code){
console.log('ConnectAbility onFailed Callback')
}
```
}
```
The following code snippet shows how to connect to a local Service ability:
The following code snippet shows how to connect to a local Service ability:
```javascript
import featureAbility from '@ohos.ability.featureAbility';
let connId = featureAbility.connectAbility(
```javascript
import featureAbility from '@ohos.ability.featureAbility';
let connId = featureAbility.connectAbility(
{
bundleName: "com.jstest.serviceability",
abilityName: "com.jstest.serviceability.MainAbility",
bundleName: "com.jstest.service",
abilityName: "com.jstest.service.ServiceAbility",
},
{
onConnect: onConnectCallback,
onDisconnect: onDisconnectCallback,
onFailed: onFailedCallback,
},
);
```
);
```
When a Service ability is connected, the **onConnect()** callback is invoked and returns an **IRemoteObject** defining the proxy used for communicating with the Service ability. OpenHarmony provides a default implementation of the **IRemoteObject** interface. You can inherit **rpc.RemoteObject** to implement your own class of **IRemoteObject**.
When a Service ability is connected, the **onConnect()** callback is invoked and returns an **IRemoteObject** defining the proxy used for communicating with the Service ability. OpenHarmony provides a default implementation of **IRemoteObject**. You can extend **rpc.RemoteObject** to implement your own class of **IRemoteObject**.
The following code snippet shows how the Service ability instance returns itself to the calling ability:
The following code snippet shows how the Service ability instance returns itself to the calling ability:
```javascript
import rpc from "@ohos.rpc";
```javascript
import rpc from "@ohos.rpc";
let mMyStub;
export default {
let mMyStub;
export default {
onStart() {
class MyStub extends rpc.RemoteObject{
constructor(des) {
......@@ -210,19 +235,24 @@ export default {
onStop() {
console.log('ServiceAbility onStop');
},
}
```
}
```
### Connecting to a Remote Service Ability (Applying only to System Applications)
### Connecting to a Remote Service Ability<a name="section126857614019"></a> (Applying only to System Applications)
>Note: The **getTrustedDeviceListSync** API of the **DeviceManager** class is open only to system applications. Therefore, remote Service ability startup applies only to system applications.
>**NOTE**
>
>This feature applies only to system applications, since the **getTrustedDeviceListSync** API of the **DeviceManager** class is open only to system applications.
If you need to connect a Service ability to a Page ability on another device or to a Service ability in another application on another device, you must first implement the **IAbilityConnection** interface for the connection. A Service ability allows other abilities on another device to connect to it through **connectAbility()**.
If you need to connect a Service ability to a Page ability or another Service ability on a remote device, you must first implement the **IAbilityConnection** interface for the connection. A Service ability allows abilities on another device to connect to it through **connectAbility()**.
When calling **connectAbility()**, you should pass a **Want** object containing information about the target Service ability and an **IAbilityConnection** object to the API. **IAbilityConnection** provides the following callbacks that you should implement: **onConnect()**, **onDisconnect()**, and **onFailed()**. The **onConnect()** callback is invoked when a Service ability is connected, **onDisconnect()** is invoked when a Service ability is unexpectedly disconnected, and **onFailed()** is invoked when a connection to a Service ability fails.
The following code snippet shows how to implement the callbacks:
```ts
import prompt from '@system.prompt'
let mRemote;
function onConnectCallback(element, remote){
console.log('onConnectRemoteService onConnectDone element: ' + element);
......@@ -264,7 +294,10 @@ The **Want** of the target Service ability must contain the remote **deviceId**,
```ts
import deviceManager from '@ohos.distributedHardware.deviceManager';
// For details about the implementation of dmClass, see the implementation in Distributed Demo in Samples.
let dmClass;
function getRemoteDeviceId() {
if (typeof dmClass === 'object' && dmClass != null) {
let list = dmClass.getTrustedDeviceListSync();
......@@ -327,15 +360,12 @@ async function RequestPermission() {
let context = featureAbility.getContext();
context.requestPermissionsFromUser(requestPermissions, 1, (data)=>{
console.info("data:" + JSON.stringify(data));
console.info("data requestCode:" + data.requestCode);
console.info("data permissions:" + data.permissions);
console.info("data authResults:" + data.authResults);
});
console.info('RequestPermission end');
}
```
When a Service ability is connected, the **onConnect()** callback is invoked and returns an **IRemoteObject** defining the proxy used for communicating with the Service ability. OpenHarmony provides a default implementation of the **IRemoteObject** interface. You can inherit **rpc.RemoteObject** to implement your own class of **IRemoteObject**.
When a Service ability is connected, the **onConnect()** callback is invoked and returns an **IRemoteObject** defining the proxy used for communicating with the Service ability. OpenHarmony provides a default implementation of **IRemoteObject**. You can extend **rpc.RemoteObject** to implement your own class of **IRemoteObject**.
The following code snippet shows how the Service ability instance returns itself to the calling ability:
......@@ -398,5 +428,5 @@ export default {
## Samples
The following samples are provided to help you better understand how to develop a Service ability:
- [`ServiceAbility`: Service Ability Creation and Use (eTS) (API8)](https://gitee.com/openharmony/app_samples/tree/master/ability/ServiceAbility)
- [`DMS`: Distributed Demo (eTS) (API7)](https://gitee.com/openharmony/app_samples/tree/master/ability/DMS)
- [`ServiceAbility`: Service Ability Creation and Use (eTS, API version 8)](https://gitee.com/openharmony/app_samples/tree/master/ability/ServiceAbility)
- [`DMS`: Distributed Demo (eTS, API version 8)](https://gitee.com/openharmony/app_samples/tree/master/ability/DMS)
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