HarmonyOS 应用开发之多端协同

2024-11-30 来源：个人技术集锦

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

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
@Component
struct 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
@Component
struct 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
@Component
struct 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
@Component
struct 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
@Component
struct 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

接口名	描述
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
@Component
struct 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
@Component
struct 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<rpc.MessageSequence>	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"。

Json字段	字段说明
“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。

1.导入UIAbility模块。

import UIAbility from '@ohos.app.ability.UIAbility';

2.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
@Component
struct 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。
1. 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<void> {
    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<void> {
    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}`);
    };
  }
}

总是有很多小伙伴反馈说：鸿蒙开发不知道学习哪些技术？不知道需要重点掌握哪些鸿蒙应用开发知识点？ 为了解决大家这些学习烦恼。在这准备了一份很实用的鸿蒙（HarmonyOS NEXT）学习路线与学习文档给大家用来跟着学习。

针对一些列因素，整理了一套纯血版鸿蒙（HarmonyOS Next）全栈开发技术的学习路线，包含了鸿蒙开发必掌握的核心知识要点，内容有（ArkTS、ArkUI开发组件、Stage模型、多端部署、分布式应用开发、WebGL、元服务、OpenHarmony多媒体技术、Napi组件、OpenHarmony内核、OpenHarmony驱动开发、系统定制移植等等）鸿蒙（HarmonyOS NEXT）技术知识点。

《鸿蒙 (Harmony OS)开发学习手册》（共计892页）:

如何快速入门？

1.基本概念
2.构建第一个ArkTS应用
3.……

开发基础知识

1.应用基础知识
2.配置文件
3.应用数据管理
4.应用安全管理
5.应用隐私保护
6.三方应用调用管控机制
7.资源分类与访问
8.学习ArkTS语言
9.……

基于ArkTS 开发

1.Ability开发
2.UI开发
3.公共事件与通知
4.窗口管理
5.媒体
6.安全
7.网络与链接
8.电话服务
9.数据管理
10.后台任务(Background Task)管理
11.设备管理
12.设备使用信息统计
13.DFX
14.国际化开发
15.折叠屏系列
16.……

鸿蒙开发面试真题（含参考答案）:

OpenHarmony 开发环境搭建:

《OpenHarmony源码解析》:

搭建开发环境
系统架构分析

构建子系统
启动流程
子系统
分布式任务调度子系统
分布式通信子系统
驱动子系统
……

OpenHarmony 设备开发学习手册:

显示全文

全部栏目

HarmonyOS 应用开发之多端协同

多端协同流程

约束限制

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

接口说明

开发步骤

通过跨设备启动UIAbility组件实现多端协同（获取返回数据）

接口说明

开发步骤

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

接口说明

开发步骤

通过跨设备Call调用实现多端协同

接口说明

开发步骤

《鸿蒙 (Harmony OS)开发学习手册》（共计892页）:

如何快速入门？

开发基础知识

基于ArkTS 开发

鸿蒙开发面试真题（含参考答案）:

OpenHarmony 开发环境搭建:

《OpenHarmony源码解析》:

OpenHarmony 设备开发学习手册: