多端协同主要应用场景介绍

多端协同

功能描述

多端协同主要包括如下场景：

通过跨设备启动UIAbility和ServiceExtensionAbility组件实现多端协同（无返回数据）
通过跨设备启动UIAbility组件实现多端协同（获取返回数据）
通过跨设备连接ServiceExtensionAbility组件实现多端协同
通过跨设备Call调用实现多端协同

多端协同流程

多端协同流程如下图所示。
图1 多端协同流程图

约束限制

由于“多端协同任务管理”能力尚未具备，开发者当前只能通过开发系统应用获取设备列表，不支持三方应用接入。
多端协同需遵循分布式跨设备组件启动规则。
为了获得最佳体验，使用want传输的数据建议在100KB以下。

通过跨设备启动UIAbility和ServiceExtensionAbility组件实现多端协同（无返回数据）

在设备A上通过发起端应用提供的启动按钮，启动设备B上指定的UIAbility与ServiceExtensionAbility。
接口说明

表1 跨设备启动API接口功能介绍
接口名描述

startAbility(want: Want, callback: AsyncCallback): void;	启动UIAbility和ServiceExtensionAbility（callback形式）。
stopServiceExtensionAbility(want: Want, callback: AsyncCallback): void;	退出启动的ServiceExtensionAbility（callback形式）。
stopServiceExtensionAbility(want: Want): Promise;	退出启动的ServiceExtensionAbility（Promise形式）。

开发步骤

需要申请ohos.permission.DISTRIBUTED_DATASYNC权限，配置方式请参见声明权限。
同时需要在应用首次启动时弹窗向用户申请授权，使用方式请参见向用户申请授权。
获取目标设备的设备ID。
import deviceManager from '@ohos.distributedDeviceManager';import hilog from '@ohos.hilog';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;let dmClass: deviceManager.DeviceManager;function initDmClass(): void { // 其中createDeviceManager接口为系统API try { dmClass = deviceManager.createDeviceManager('com.samples.stagemodelabilitydevelop'); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass) ?? ''); } catch (err) { hilog.error(DOMAIN_NUMBER, TAG, 'createDeviceManager err: ' + JSON.stringify(err)); };}function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }}
设置目标组件参数，调用startAbility()接口，启动UIAbility或ServiceExtensionAbility。
import { BusinessError } from '@ohos.base';import hilog from '@ohos.hilog';import Want from '@ohos.app.ability.Want';import deviceManager from '@ohos.distributedDeviceManager';import common from '@ohos.app.ability.common';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;let dmClass: deviceManager.DeviceManager;function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }};@Entry@Componentstruct Page_CollaborateAbility { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('startAbility') .onClick(() => { let want: Want = { deviceId: getRemoteDeviceId(), bundleName: 'com.samples.stagemodelabilityinteraction', abilityName: 'CollaborateAbility', moduleName: 'entry' // moduleName非必选 } // context为发起端UIAbility的AbilityContext this.context.startAbility(want).then(() => { // ... }).catch((err: BusinessError) => { // ... hilog.error(DOMAIN_NUMBER, TAG, `startAbility err: ` + JSON.stringify(err)); }); } ) }}
当设备A发起端应用不需要设备B上的ServiceExtensionAbility时，可调用stopServiceExtensionAbility接口退出。（该接口不支持UIAbility的退出，UIAbility由用户手动通过任务管理退出）
import Want from '@ohos.app.ability.Want';import hilog from '@ohos.hilog';import { BusinessError } from '@ohos.base';import deviceManager from '@ohos.distributedDeviceManager';import common from '@ohos.app.ability.common';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;let dmClass: deviceManager.DeviceManager;function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }};@Entry@Componentstruct Page_CollaborateAbility { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('stopServiceExtensionAbility') .onClick(() => { let want: Want = { deviceId: getRemoteDeviceId(), bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', moduleName: 'module1', // moduleName非必选 } // 退出由startAbility接口启动的ServiceExtensionAbility this.context.stopServiceExtensionAbility(want).then(() => { console.info("stop service extension ability success") }).catch((err: BusinessError) => { console.info("stop service extension ability err is " + JSON.stringify(err)) }) }) }}

通过跨设备启动UIAbility组件实现多端协同（获取返回数据）

在设备A上通过应用提供的启动按钮，启动设备B上指定的UIAbility，当设备B上的UIAbility退出后，会将返回值发回设备A上的发起端应用。
接口说明

表2 跨设备启动，返回结果数据API接口功能描述
接口名描述

startAbilityForResult(want: Want, callback: AsyncCallback): void;	启动UIAbility并在该Ability退出的时候返回执行结果（callback形式）。
terminateSelfWithResult(parameter: AbilityResult, callback: AsyncCallback): void;	停止UIAbility，配合startAbilityForResult使用，返回给接口调用方AbilityResult信息（callback形式）。
terminateSelfWithResult(parameter: AbilityResult): Promise;	停止UIAbility，配合startAbilityForResult使用，返回给接口调用方AbilityResult信息（promise形式）。

开发步骤

需要申请ohos.permission.DISTRIBUTED_DATASYNC权限，配置方式请参见声明权限。
同时需要在应用首次启动时弹窗向用户申请授权，使用方式请参见向用户申请授权。
在发起端设置目标组件参数，调用startAbilityForResult()接口启动目标端UIAbility，异步回调中的data用于接收目标端UIAbility停止自身后返回给调用方UIAbility的信息。getRemoteDeviceId方法参照通过跨设备启动uiability和serviceextensionability组件实现多端协同无返回数据。
import common from '@ohos.app.ability.common';import hilog from '@ohos.hilog';import { BusinessError } from '@ohos.base';import Want from '@ohos.app.ability.Want';import deviceManager from '@ohos.distributedDeviceManager';const DOMAIN_NUMBER: number = 0xFF00;const TAG: string = '[Page_CollaborateAbility]';let dmClass: deviceManager.DeviceManager;function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }};@Entry@Componentstruct Page_CollaborateAbility { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('多端协同有返回数据') .onClick(()=>{ let want: Want = { deviceId: getRemoteDeviceId(), bundleName: 'com.samples.stagemodelabilityinteraction', abilityName: 'CollaborateAbility', moduleName: 'entry' // moduleName非必选 }; // context为发起端UIAbility的AbilityContext this.context.startAbilityForResult(want).then((data) => { // ... }).catch((error: BusinessError) => { hilog.error(DOMAIN_NUMBER, TAG, `startAbilityForResult err: ` + JSON.stringify(error)); }) } ) }}
在目标端UIAbility任务完成后，调用terminateSelfWithResult()方法，将数据返回给发起端的UIAbility。
import common from '@ohos.app.ability.common';import hilog from '@ohos.hilog';import { BusinessError } from '@ohos.base';const DOMAIN_NUMBER: number = 0xFF00;const TAG: string = '[Page_CollaborateAbility]';@Entry@Componentstruct PageName { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('关闭多设备协同界面并返回数据') .onClick(()=>{ const RESULT_CODE: number = 1001; // context为目标端UIAbility的AbilityContext this.context.terminateSelfWithResult( { resultCode: RESULT_CODE, want: { bundleName: 'ohos.samples.stagemodelabilitydevelop', abilityName: 'CollaborateAbility', moduleName: 'entry', parameters: { info: '来自Page_CollaborateAbility页面' } } }, (err: BusinessError) => { hilog.info(DOMAIN_NUMBER, TAG, `terminateSelfWithResult err: ` + JSON.stringify(err)); }); }) }}
发起端UIAbility接收到目标端UIAbility返回的信息，对其进行处理。
import common from '@ohos.app.ability.common';import deviceManager from '@ohos.distributedDeviceManager';import hilog from '@ohos.hilog';import Want from '@ohos.app.ability.Want';import { BusinessError } from '@ohos.base';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;let dmClass: deviceManager.DeviceManager;function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }};@Entry@Componentstruct PageName { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('多端协同有返回数据') .onClick(() => { let want: Want = { deviceId: getRemoteDeviceId(), bundleName: 'com.samples.stagemodelabilityinteraction', abilityName: 'CollaborateAbility', moduleName: 'entry' // moduleName非必选 }; const RESULT_CODE: number = 1001; // ... // context为调用方UIAbility的UIAbilityContext this.context.startAbilityForResult(want).then((data) => { if (data?.resultCode === RESULT_CODE) { // 解析目标端UIAbility返回的信息 let info = data.want?.parameters?.info; // ... } }).catch((error: BusinessError) => { // ... }) } ) }}

通过跨设备连接ServiceExtensionAbility组件实现多端协同

系统应用可以通过connectServiceExtensionAbility()跨设备连接一个服务，实现跨设备远程调用。比如：分布式游戏场景，平板作为遥控器，智慧屏作为显示器。
接口说明

表3 跨设备连接API接口功能介绍
[tr]接口名描述[/tr]

connectServiceExtensionAbility(want: Want, options: ConnectOptions): number;	连接ServiceExtensionAbility。
disconnectServiceExtensionAbility(connection: number, callback:AsyncCallback): void;	断开连接（callback形式）。
disconnectServiceExtensionAbility(connection: number): Promise;	断开连接（promise形式）。

开发步骤

需要申请ohos.permission.DISTRIBUTED_DATASYNC权限，配置方式请参见声明权限。
同时需要在应用首次启动时弹窗向用户申请授权，使用方式请参见向用户申请授权。
如果已有后台服务，请直接进入下一步；如果没有，则实现一个后台服务（仅对系统应用开放）。
连接一个后台服务。
- 实现IAbilityConnection接口。IAbilityConnection提供了以下方法供开发者实现：onConnect()是用来处理连接Service成功的回调，onDisconnect()是用来处理Service异常终止的回调，onFailed()是用来处理连接Service失败的回调。
- 设置目标组件参数，包括目标设备ID、Bundle名称、Ability名称。
- 调用connectServiceExtensionAbility发起连接。
- 连接成功，收到目标设备返回的服务句柄。
- 进行跨设备调用，获得目标端服务返回的结果。
  import common from '@ohos.app.ability.common';import deviceManager from '@ohos.distributedDeviceManager';import hilog from '@ohos.hilog';import rpc from '@ohos.rpc';import Want from '@ohos.app.ability.Want';import { BusinessError } from '@ohos.base';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;const REQUEST_CODE = 1;let dmClass: deviceManager.DeviceManager;let connectionId: number;let options: common.ConnectOptions = { onConnect(elementName, remote) { hilog.info(DOMAIN_NUMBER, TAG, 'onConnect callback'); if (remote === null) { hilog.info(DOMAIN_NUMBER, TAG, `onConnect remote is null`); return; } let option = new rpc.MessageOption(); let data = new rpc.MessageSequence(); let reply = new rpc.MessageSequence(); data.writeInt(99); // 开发者可发送data到目标端应用进行相应操作 // @param code 表示客户端发送的服务请求代码。 // @param data 表示客户端发送的{@link MessageSequence}对象。 // @param reply 表示远程服务发送的响应消息对象。 // @param options 指示操作是同步的还是异步的。 // // @return 如果操作成功返回{@code true}；否则返回 {@code false}。 remote.sendMessageRequest(REQUEST_CODE, data, reply, option).then((ret: rpc.RequestResult) => { let errCode = reply.readInt(); // 在成功连接的情况下，会收到来自目标端返回的信息（100） let msg: number = 0; if (errCode === 0) { msg = reply.readInt(); } // 成功连接后台服务 hilog.info(DOMAIN_NUMBER, TAG, `sendRequest msg:${msg}`); }).catch((error: BusinessError) => { hilog.info(DOMAIN_NUMBER, TAG, `sendRequest failed, ${JSON.stringify(error)}`); }); }, onDisconnect(elementName) { hilog.info(DOMAIN_NUMBER, TAG, 'onDisconnect callback'); }, onFailed(code) { hilog.info(DOMAIN_NUMBER, TAG, 'onFailed callback'); }};function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }}@Entry@Componentstruct PageName { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('connectServiceExtensionAbility') .onClick(()=>{ let want: Want = { 'deviceId': getRemoteDeviceId(), 'bundleName': 'com.samples.stagemodelabilityinteraction', 'abilityName': 'ServiceExtAbility' }; // 建立连接后返回的Id需要保存下来，在解绑服务时需要作为参数传入 connectionId = this.context.connectServiceExtensionAbility(want, options); }) }}getRemoteDeviceId方法参照通过跨设备启动uiability和serviceextensionability组件实现多端协同无返回数据。
断开连接。调用disconnectServiceExtensionAbility()断开与后台服务的连接。
import common from '@ohos.app.ability.common';import { BusinessError } from '@ohos.base';import hilog from '@ohos.hilog';import Want from '@ohos.app.ability.Want';import rpc from '@ohos.rpc';import IdlServiceExtProxy from '../IdlServiceExt/idl_service_ext_proxy';let connectionId: number;const TAG: string = '[Page_ServiceExtensionAbility]';const DOMAIN_NUMBER: number = 0xFF00;let want: Want = { deviceId: '', bundleName: 'com.samples.stagemodelabilitydevelop', abilityName: 'ServiceExtAbility'};let options: common.ConnectOptions = { onConnect(elementName, remote: rpc.IRemoteObject): void { hilog.info(DOMAIN_NUMBER, TAG, 'onConnect callback'); if (remote === null) { hilog.info(DOMAIN_NUMBER, TAG, 'onConnect remote is null'); return; } let serviceExtProxy: IdlServiceExtProxy = new IdlServiceExtProxy(remote); // 通过接口调用的方式进行通信，屏蔽了RPC通信的细节，简洁明了 serviceExtProxy.processData(1, (errorCode: number, retVal: number) => { hilog.info(DOMAIN_NUMBER, TAG, `processData, errorCode: ${errorCode}, retVal: ${retVal}`); }); serviceExtProxy.insertDataToMap('theKey', 1, (errorCode: number) => { hilog.info(DOMAIN_NUMBER, TAG, `insertDataToMap, errorCode: ${errorCode}`); }) }, onDisconnect(elementName): void { hilog.info(DOMAIN_NUMBER, TAG, 'onDisconnect callback'); }, onFailed(code: number): void { hilog.info(DOMAIN_NUMBER, TAG, 'onFailed callback', JSON.stringify(code)); }};@Entry@Componentstruct PageName { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('disconnectServiceExtensionAbility') .onClick(() => { this.context.disconnectServiceExtensionAbility(connectionId).then(() => { connectionId = this.context.connectServiceExtensionAbility(want, options); hilog.info(DOMAIN_NUMBER, TAG, 'disconnectServiceExtensionAbility success'); // 成功断连后台服务 }).catch((error: BusinessError) => { hilog.error(DOMAIN_NUMBER, TAG, 'disconnectServiceExtensionAbility failed'); }) }) }}

通过跨设备Call调用实现多端协同

跨设备Call调用的基本原理与设备内Call调用相同，请参见通过Call调用实现UIAbility交互（仅对系统应用开放）。
下面介绍跨设备Call调用实现多端协同的方法。
接口说明

表4 Call API接口功能介绍
接口名描述

startAbilityByCall(want: Want): Promise;	启动指定UIAbility至前台或后台，同时获取其Caller通信接口，调用方可使用Caller与被启动的Ability进行通信。
on(method: string, callback: CalleeCallBack): void	通用组件Callee注册method对应的callback方法。
off(method: string): void	通用组件Callee解注册method的callback方法。
call(method: string, data: rpc.Parcelable): Promise	向通用组件Callee发送约定序列化数据。
callWithResult(method: string, data: rpc.Parcelable): Promise	向通用组件Callee发送约定序列化数据, 并将Callee返回的约定序列化数据带回。
release(): void	释放通用组件的Caller通信接口。
on(type: “release”, callback: OnReleaseCallback): void	注册通用组件通信断开监听通知。

开发步骤

需要申请ohos.permission.DISTRIBUTED_DATASYNC权限，配置方式请参见声明权限。
同时需要在应用首次启动时弹窗向用户申请授权，使用方式请参见向用户申请授权。
创建被调用端UIAbility。被调用端UIAbility需要实现指定方法的数据接收回调函数、数据的序列化及反序列化方法。在需要接收数据期间，通过on接口注册监听，无需接收数据时通过off接口解除监听。
- 配置UIAbility的启动模式。配置module.json5，将CalleeAbility配置为单实例"singleton"。
  [tr]Json字段字段说明[/tr]
  “launchType” Ability的启动模式，设置为"singleton"类型。
  UIAbility配置标签示例如下：
  "abilities":[{ "name": ".CalleeAbility", "srcEntry": "./ets/CalleeAbility/CalleeAbility.ts", "launchType": "singleton", "description": "$string:CalleeAbility_desc", "icon": "$media:icon", "label": "$string:CalleeAbility_label", "exported": true}]
- 导入UIAbility模块。
  import UIAbility from '@ohos.app.ability.UIAbility';
- 定义约定的序列化数据。调用端及被调用端发送接收的数据格式需协商一致，如下示例约定数据由number和string组成。
  import rpc from '@ohos.rpc'class MyParcelable { num: number = 0; str: string = ''; constructor(num: number, string: string) { this.num = num; this.str = string; } mySequenceable(num: number, string: string): void { this.num = num; this.str = string; } marshalling(messageSequence: rpc.MessageSequence): boolean { messageSequence.writeInt(this.num); messageSequence.writeString(this.str); return true; }; unmarshalling(messageSequence: rpc.MessageSequence): boolean { this.num = messageSequence.readInt(); this.str = messageSequence.readString(); return true; };};
- 实现Callee.on监听及Callee.off解除监听。如下示例在Ability的onCreate注册MSG_SEND_METHOD监听，在onDestroy取消监听，收到序列化数据后作相应处理并返回。应用开发者根据实际业务需要做相应处理。
  import type AbilityConstant from '@ohos.app.ability.AbilityConstant';import UIAbility from '@ohos.app.ability.UIAbility';import type Want from '@ohos.app.ability.Want';import hilog from '@ohos.hilog';import type rpc from '@ohos.rpc';import type { Caller } from '@ohos.app.ability.UIAbility';const TAG: string = '[CalleeAbility]';const MSG_SEND_METHOD: string = 'CallSendMsg';const DOMAIN_NUMBER: number = 0xFF00;class MyParcelable { num: number = 0; str: string = ''; constructor(num: number, string: string) { this.num = num; this.str = string; }; mySequenceable(num: number, string: string): void { this.num = num; this.str = string; }; marshalling(messageSequence: rpc.MessageSequence): boolean { messageSequence.writeInt(this.num); messageSequence.writeString(this.str); return true; }; unmarshalling(messageSequence: rpc.MessageSequence): boolean { this.num = messageSequence.readInt(); this.str = messageSequence.readString(); return true; };};function sendMsgCallback(data: rpc.MessageSequence): rpc.Parcelable { hilog.info(DOMAIN_NUMBER, TAG, '%{public}s', 'CalleeSortFunc called'); // 获取Caller发送的序列化数据 let receivedData: MyParcelable = new MyParcelable(0, ''); data.readParcelable(receivedData); hilog.info(DOMAIN_NUMBER, TAG, '%{public}s', `receiveData[${receivedData.num}, ${receivedData.str}]`); let num: number = receivedData.num; // 作相应处理 // 返回序列化数据result给Caller return new MyParcelable(num + 1, `send ${receivedData.str} succeed`) as rpc.Parcelable;}export default class CalleeAbility extends UIAbility { caller: Caller | undefined; onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void { try { this.callee.on(MSG_SEND_METHOD, sendMsgCallback); } catch (error) { hilog.error(DOMAIN_NUMBER, TAG, '%{public}s', `Failed to register. Error is ${error}`) }; } onDestroy(): void { try { this.callee.off(MSG_SEND_METHOD); hilog.info(DOMAIN_NUMBER, TAG, '%{public}s', 'Callee OnDestroy'); this.releaseCall(); } catch (error) { hilog.error(DOMAIN_NUMBER, TAG, '%{public}s', `Failed to register. Error is ${error}`) }; }}
获取Caller接口，访问被调用端UIAbility。
- 导入UIAbility模块。
  import UIAbility from '@ohos.app.ability.UIAbility';
- 获取Caller通信接口。Ability的context属性实现了startAbilityByCall方法，用于获取指定通用组件的Caller通信接口。如下示例通过this.context获取Ability实例的context属性，使用startAbilityByCall拉起Callee被调用端并获取Caller通信接口，注册Caller的onRelease和onRemoteStateChange监听。应用开发者根据实际业务需要做相应处理。
  import { Caller } from '@ohos.app.ability.UIAbility';import { BusinessError } from '@ohos.base';import common from '@ohos.app.ability.common';import deviceManager from '@ohos.distributedDeviceManager';import hilog from '@ohos.hilog';const TAG: string = '[Page_CollaborateAbility]';const DOMAIN_NUMBER: number = 0xFF00;let caller: Caller | undefined;let dmClass: deviceManager.DeviceManager;function getRemoteDeviceId(): string | undefined { if (typeof dmClass === 'object' && dmClass !== null) { let list = dmClass.getAvailableDeviceListSync(); hilog.info(DOMAIN_NUMBER, TAG, JSON.stringify(dmClass), JSON.stringify(list)); if (typeof (list) === 'undefined' || typeof (list.length) === 'undefined') { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: list is null'); return; } if (list.length === 0) { hilog.info(DOMAIN_NUMBER, TAG, `getRemoteDeviceId err: list is empty`); return; } return list[0].networkId; } else { hilog.info(DOMAIN_NUMBER, TAG, 'getRemoteDeviceId err: dmClass is null'); return; }}@Entry@Componentstruct Page_CollaborateAbility { private context = getContext(this) as common.UIAbilityContext; build() { // ... Button('多端协同有返回数据') .onClick(() => { this.context.startAbilityByCall({ deviceId: getRemoteDeviceId(), bundleName: 'com.samples.stagemodelabilityinteraction', abilityName: 'CalleeAbility' }).then((data) => { if (data !== null) { caller = data; hilog.info(DOMAIN_NUMBER, TAG, 'get remote caller success'); // 注册caller的release监听 caller.onRelease((msg) => { hilog.info(DOMAIN_NUMBER, TAG, `remote caller onRelease is called ${msg}`); }) hilog.info(DOMAIN_NUMBER, TAG, 'remote caller register OnRelease succeed'); // 注册caller的协同场景下跨设备组件状态变化监听通知 try { caller.onRemoteStateChange((str) => { hilog.info(DOMAIN_NUMBER, TAG, 'Remote state changed ' + str); }); } catch (error) { hilog.info(DOMAIN_NUMBER, TAG, `Caller.onRemoteStateChange catch error, error.code: ${JSON.stringify(error.code)}, error.message: ${JSON.stringify(error.message)}`); }; } }).catch((error: BusinessError) => { hilog.error(DOMAIN_NUMBER, TAG, `get remote caller failed with ${error}`); }); } ) }}getRemoteDeviceId方法参照通过跨设备启动uiability和serviceextensionability组件实现多端协同无返回数据。
向被调用端UIAbility发送约定序列化数据。
- 向被调用端发送Parcelable数据有两种方式，一种是不带返回值，一种是获取被调用端返回的数据，method以及序列化数据需要与被调用端协商一致。如下示例调用Call接口，向Callee被调用端发送数据。
  import UIAbility, { Caller } from '@ohos.app.ability.UIAbility';import type rpc from '@ohos.rpc';const MSG_SEND_METHOD: string = 'CallSendMsg';class MyParcelable { num: number = 0; str: string = ''; constructor(num: number, string: string) { this.num = num; this.str = string; }; mySequenceable(num: number, string: string): void { this.num = num; this.str = string; }; marshalling(messageSequence: rpc.MessageSequence): boolean { messageSequence.writeInt(this.num); messageSequence.writeString(this.str); return true; }; unmarshalling(messageSequence: rpc.MessageSequence): boolean { this.num = messageSequence.readInt(); this.str = messageSequence.readString(); return true; };};export default class EntryAbility extends UIAbility { // ... caller: Caller | undefined; async onButtonCall(): Promise { try { let msg: MyParcelable = new MyParcelable(1, 'origin_Msg'); if (this.caller) { await this.caller.call(MSG_SEND_METHOD, msg); } } catch (error) { hilog.info(DOMAIN_NUMBER, TAG, `caller call failed with ${error}`); }; } // ...}
- 如下示例调用CallWithResult接口，向Callee被调用端发送待处理的数据originMsg，并将’CallSendMsg’方法处理完毕的数据赋值给backMsg。
  import UIAbility, { Caller } from '@ohos.app.ability.UIAbility';import rpc from '@ohos.rpc';const MSG_SEND_METHOD: string = 'CallSendMsg';let originMsg: string = '';let backMsg: string = '';class MyParcelable { num: number = 0; str: string = ''; constructor(num: number, string: string) { this.num = num; this.str = string; }; mySequenceable(num: number, string: string): void { this.num = num; this.str = string; }; marshalling(messageSequence: rpc.MessageSequence): boolean { messageSequence.writeInt(this.num); messageSequence.writeString(this.str); return true; }; unmarshalling(messageSequence: rpc.MessageSequence): boolean { this.num = messageSequence.readInt(); this.str = messageSequence.readString(); return true; };};export default class EntryAbility extends UIAbility { // ... caller: Caller | undefined; async onButtonCallWithResult(originMsg: string, backMsg: string): Promise { try { let msg: MyParcelable = new MyParcelable(1, originMsg); if (this.caller) { const data = await this.caller.callWithResult(MSG_SEND_METHOD, msg); hilog.info(DOMAIN_NUMBER, TAG, 'caller callWithResult succeed'); let result: MyParcelable = new MyParcelable(0, ''); data.readParcelable(result); backMsg = result.str; hilog.info(DOMAIN_NUMBER, TAG, `caller result is [${result.num}, ${result.str}]`); } } catch (error) { hilog.info(DOMAIN_NUMBER, TAG, `caller callWithResult failed with ${error}`); }; } // ...}
释放Caller通信接口。Caller不再使用后，应用开发者可以通过release接口释放Caller。
import UIAbility, { Caller } from '@ohos.app.ability.UIAbility';export default class EntryAbility extends UIAbility { caller: Caller | undefined; releaseCall(): void { try { if (this.caller) { this.caller.release(); this.caller = undefined; } hilog.info(DOMAIN_NUMBER, TAG, 'caller release succeed'); } catch (error) { hilog.info(DOMAIN_NUMBER, TAG, `caller release failed with ${error}`); }; }}

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