介绍

在HarmonyOS中，参考官方指导，其实你会发现在‘指南’和‘API参考’两个文档中，对消息传递使用的技术不是一对一的关系，那么今天这篇文章带你全面了解HarmonyOS 中的消息传递

概况

参照官方指导，我总结了两部分：1. 官方“指南”，即下图中的“Stage模型” 2. 总结的内容，即“消息事件” 消息事件传递技术.png

开始

EventHub

这个其实是可以帮大家解决几个最常见的消息传递场景：1. UIAbility和其它 2.页面和其它 3. 组件和其它

官方指导

样例

1. 订阅

this.context.eventHub.on('onConfigurationUpdate', (data) => {
    //订阅

});

2. 发送

let eventhub = this.context.eventHub;
eventhub.emit('onConfigurationUpdate', config);

3. 解除订阅

this.context.eventHub.off('onConfigurationUpdate')

CommonEvent

参照官方指南，其总称简写为CES(全称：Common Event Service），可以监听系统锁屏，时间变化，等等

1. 订阅

usual.event.TIME_TICK ：系统公共事件
harvey.event.CUSTOM_1 ：自定义事件

let subscribeInfo = {
  events: ["usual.event.TIME_TICK", 'harvey.event.CUSTOM_1']
}

// 1. 创建订阅者
commonEventManager.createSubscriber(subscribeInfo, (err, subscriber) => {
  if (err) {
    console.error(`Failed to create subscriber. Code is ${err.code}, message is ${err.message}`);
    return;
  }
  console.info('Succeeded in creating subscriber.' + JSON.stringify(subscriber));

  this.subscriberID = subscriber

  // 2. 订阅事件回调
  commonEventManager.subscribe(subscriber, (err, commonEventData) => {
    if (err) {
      console.error(`Failed to subscribe common event. Code is ${err.code}, message is ${err.message}`);
      return;
    } else {
      systemDateTime.getCurrentTime(false, (error, data) => {
        this.mySubscriberInfo = data + '<=>' + JSON.stringify(commonEventData, null, '\t')
      })
    }
  })
})

2. 发送

对于系统级别的公共事件，三方应用无权发送公共事件（即，即使你发送了，也是不会被收到的）
但是你可以自定义自己的公共事件

commonEventManager.publish('harvey.event.CUSTOM_1', option, (error) => {
  console.log(JSON.stringify(error))
})

3. 解除订阅

解除时用的是订阅者ID

commonEventManager.unsubscribe(this.subscriberID);

Emitter

1. 订阅

必须要有eventId, 这个代表消息的唯一标识

let innerEvent = {
  eventId: 1847
};

emitter.on(innerEvent, (eventData) => {
   this.emitterData = process.tid + ' ' + JSON.stringify(eventData)
});

2. 发送

let eventData = {
  data: {
    'count': this.emitterCount++,
    'from': 'emitter',
    "content": "c",
    "id": 1,
  }};
let innerEvent = {
  eventId: 1847,
  priority: emitter.EventPriority.HIGH
};
emitter.emit(innerEvent, eventData);

3. 解除订阅

emitter.off(1847)

Worker

1. 订阅

import worker from '@ohos.worker';

let wk1 = new worker.ThreadWorker("/entry/ets/workers/Worker.ts")

wk1.onmessage = (msg) => {

}

2. 发送

a）从worker线程中发送

import worker, { ThreadWorkerGlobalScope, MessageEvents, ErrorEvent } from '@ohos.worker';

var workerPort : ThreadWorkerGlobalScope = worker.workerPort;

workerPort.postMessage(
  {
    ......
  }
)

b) 从主线程中发送

wk1.dispatchEvent({type: 'message', timeStamp: 0})

3. 解除订阅

//第一种
wk1.off('message')
//第二种
wk1.removeEventListener('message')
//第三种：强制关闭线程
wk1..terminate()

TaskTool 和 Notification

总结

HarmonyOS是一个新系统，还是要实践才可能在真实的业务开发中灵活运用

实践代码效果

公共事件代码

import commonEventManager from '@ohos.commonEventManager';
import systemDateTime from '@ohos.systemDateTime';

/**
 * https://developer.harmonyos.com/cn/docs/documentation/doc-references-V3/commoneventmanager-definitions-0000001493424344-V3#ZH-CN_TOPIC_0000001523808522__common_event_time_tick
 *
 */
@Entry
@Component
struct CommonEventIndex {

  @State mySubscriberInfo: string = '下一分钟会更新的'

  private subscriberID

  @State count: number = 0

  aboutToAppear() {

    let subscribeInfo = {
      events: ["usual.event.TIME_TICK", 'harvey.event.CUSTOM_1']
    }

    // 创建订阅者回调
    commonEventManager.createSubscriber(subscribeInfo, (err, subscriber) => {
      if (err) {
        console.error(`Failed to create subscriber. Code is ${err.code}, message is ${err.message}`);
        return;
      }
      console.info('Succeeded in creating subscriber.' + JSON.stringify(subscriber));

      this.subscriberID = subscriber

      // 订阅公共事件回调
      commonEventManager.subscribe(subscriber, (err, commonEventData) => {
        if (err) {
          console.error(`Failed to subscribe common event. Code is ${err.code}, message is ${err.message}`);
          return;
        } else {
          systemDateTime.getCurrentTime(false, (error, data) => {
            this.mySubscriberInfo = data + '<=>' + JSON.stringify(commonEventData, null, '\t')
          })
        }
      })
    })

  }

  aboutToDisappear(){
    commonEventManager.unsubscribe(this.subscriberID);
  }

  build() {

    Column(){
      Text(this.mySubscriberInfo)
        .width('100%')
        .fontColor(Color.Black)
        .fontSize(20)
        .textAlign(TextAlign.Center)

      Button('发布自定义公共事件').onClick(()=>{

        let option = {
          code: 0,
          data: JSON.stringify({'hello': 'word'}),
          isOrdered: true,
          // isSticky: true, 仅限系统应用&服务
          parameters: {
            'who': 'am i',
            'count': this.count++
          }
        }

        commonEventManager.publish('harvey.event.CUSTOM_1', option, (error) => {
          console.log(JSON.stringify(error))
        })
      })
    }.width('100%').height('100%')

    .justifyContent(FlexAlign.Center)
    .alignItems(HorizontalAlign.Center)

  }


}

线程代码

import emitter from '@ohos.events.emitter'
import worker from '@ohos.worker';
import process from '@ohos.process';
import Prompt from '@system.prompt';

/**
 * 依据官方指导，最多只能创建8个worker
 *
 */
let wk1 = new worker.ThreadWorker("/entry/ets/workers/Worker.ts")
let wk2 = new worker.ThreadWorker("/entry/ets/workers/Worker2.ts")
let wk3 = new worker.ThreadWorker("/entry/ets/workers/Worker3.ts")
let wk4 = new worker.ThreadWorker("/entry/ets/workers/Worker4.ts")
let wk5 = new worker.ThreadWorker("/entry/ets/workers/Worker5.ts")
let wk6 = new worker.ThreadWorker("/entry/ets/workers/Worker6.ts")
let wk7 = new worker.ThreadWorker("/entry/ets/workers/Worker7.ts")
let wk8 = new worker.ThreadWorker("/entry/ets/workers/Worker8.ts")


@Entry
@Component
struct ThreadModelIndex {

  @State emitterData: string = ''
  emitterCount: number = 0

  @State worker1Color: number = 0
  @State worker2Color: number = 0
  @State worker3Color: number = 0
  @State worker4Color: number = 0
  @State worker5Color: number = 0
  @State worker6Color: number = 0
  @State worker7Color: number = 0
  @State worker8Color: number = 0

  @State workerData: string = ''

  workerTotal: number = 8;

  async count() {
    this.workerTotal--

    if(this.workerTotal == 0){
      Prompt.showToast({message: '8个任务已完成'})
    }

  }

  aboutToDisappear(){
    wk1.terminate()
    wk2.terminate()
    wk3.terminate()
    wk4.terminate()
    wk5.terminate()
    wk6.terminate()
    wk7.terminate()
    wk8.terminate()
  }

  aboutToAppear() {

    // 处理来自worker线程的消息
    wk1.onmessage = function(message) {
      console.log("message from worker: " + JSON.stringify(message))
    }

    wk1.onmessage = (msg) => {

      if(msg && msg.data){
        if(msg.data.no == 1){
          this.worker1Color = Color.Green
        } else {
          this.worker1Color = Color.Orange
        }
        this.count()
      }

    }

    wk1.addEventListener("message", (e)=>{
      this.workerData = JSON.stringify(e)
      console.log("message listener callback: " + JSON.stringify(e));
    })

    wk1.addEventListener("WorkerTest", (e)=>{
      this.workerData = JSON.stringify(e)
    })

    wk2.onmessage = (msg) => {
      if(msg.data.no == 2){
        this.worker2Color = Color.Green
      } else {
        this.worker2Color = Color.Orange
      }
      this.count()
    }
    wk3.onmessage = (msg) => {
      if(msg.data.no == 3){
        this.worker3Color = Color.Green
      } else {
        this.worker3Color = Color.Orange
      }
      this.count()
    }
    wk4.onmessage = (msg) => {
      if(msg.data.no == 4){
        this.worker4Color = Color.Green
      } else {
        this.worker4Color = Color.Orange
      }
      this.count()
    }
    wk5.onmessage = (msg) => {
      if(msg.data.no == 5){
        this.worker5Color = Color.Green
      } else {
        this.worker5Color = Color.Orange
      }
      this.count()
    }
    wk6.onmessage = (msg) => {
      if(msg.data.no == 6){
        this.worker6Color = Color.Green
      } else {
        this.worker6Color = Color.Orange
      }
      this.count()
    }
    wk7.onmessage = (msg) => {
      if(msg.data.no == 7){
        this.worker7Color = Color.Green
      } else {
        this.worker7Color = Color.Orange
      }
      this.count()
    }
    wk8.onmessage = (msg) => {
      if(msg.data.no == 8){
        this.worker8Color = Color.Green
      } else {
        this.worker8Color = Color.Orange
      }
      this.count()
    }

    let innerEvent = {
      eventId: 1847
    };

    emitter.on(innerEvent, (eventData) => {
       this.emitterData = process.tid + ' ' + JSON.stringify(eventData)
    });

  }


  build() {

    Column(){
      Text('主线程ID: ' + process.tid)

      Text(this.emitterData).fontSize(25).textAlign(TextAlign.Center).margin({top: 20})

      Text('发送 emitter 消息')
        .fontSize(20)
        .fontColor(Color.White)
        .borderRadius('12vp')
        .backgroundColor(Color.Blue)
        .padding(10)
        .stateStyles({
          focused: {
            .backgroundColor(Color.Green)
          },
          pressed: {
            .backgroundColor(Color.Green)
          },
          normal: {
            .backgroundColor(Color.Blue)
          }
        })
        .onClick(()=>{

            let eventData = {
              data: {
                'count': this.emitterCount++,
                'from': 'emitter',
                "content": "c",
                "id": 1,
              }};
            let innerEvent = {
              eventId: 1847,
              priority: emitter.EventPriority.HIGH
            };
            emitter.emit(innerEvent, eventData);

        })
        .margin({top: 20})

      Row(){
        Text('1').fontSize(40).backgroundColor(this.worker1Color).fontColor(Color.White)
        Text('2').fontSize(40).backgroundColor(this.worker2Color).fontColor(Color.White)
        Text('3').fontSize(40).backgroundColor(this.worker3Color).fontColor(Color.White)
        Text('4').fontSize(40).backgroundColor(this.worker4Color).fontColor(Color.White)
        Text('5').fontSize(40).backgroundColor(this.worker5Color).fontColor(Color.White)
        Text('6').fontSize(40).backgroundColor(this.worker6Color).fontColor(Color.White)
        Text('7').fontSize(40).backgroundColor(this.worker7Color).fontColor(Color.White)
        Text('8').fontSize(40).backgroundColor(this.worker8Color).fontColor(Color.White)
      }
      .width('100%')
      .margin({top: 20})
      .justifyContent(FlexAlign.SpaceEvenly)

      Text('Worker-postMessage')
        .fontSize(20)
        .fontColor(Color.White)
        .borderRadius('12vp')
        .backgroundColor(Color.Blue)
        .padding(10)
        .stateStyles({
          focused: {
            .backgroundColor(Color.Green)
          },
          pressed: {
            .backgroundColor(Color.Green)
          },
          normal: {
            .backgroundColor(Color.Blue)
          }
        })
        .onClick(()=>{
           this.worker1Color = Color.Black
           this.worker2Color = Color.Black
           this.worker3Color = Color.Black
           this.worker4Color = Color.Black
           this.worker5Color = Color.Black
           this.worker6Color = Color.Black
           this.worker7Color = Color.Black
           this.worker8Color = Color.Black

          let tid = process.tid;

          console.log('当前进程ID ：' + tid)

          // 发送消息到worker线程
          wk1.postMessage({'no':1,'threadID': tid,  'costtime': 1000})
          wk2.postMessage({'no':2,'threadID': tid, 'costtime': 1500})
          wk3.postMessage({'no':3,'threadID': tid, 'costtime': 2000})
          wk4.postMessage({'no':4,'threadID': tid, 'costtime': 2500})
          wk5.postMessage({'no':5,'threadID': tid, 'costtime': 3000})
          wk6.postMessage({'no':6,'threadID': tid, 'costtime': 3500})
          wk7.postMessage({'no':7,'threadID': tid, 'costtime': 4000})
          wk8.postMessage({'no':8,'threadID': tid, 'costtime': 4500})

        })
        .margin({top: 20})

      Text(this.workerData).fontSize(25).textAlign(TextAlign.Center)

      Text('Worker-dispatchEvent-自定义类型')
        .fontSize(20)
        .fontColor(Color.White)
        .borderRadius('12vp')
        .backgroundColor(Color.Blue)
        .padding(10)
        .stateStyles({
          focused: {
            .backgroundColor(Color.Green)
          },
          pressed: {
            .backgroundColor(Color.Green)
          },
          normal: {
            .backgroundColor(Color.Blue)
          }
        })
        .onClick(()=>{

          let tid = process.tid;

          console.log('当前进程ID ：' + tid)

          wk1.dispatchEvent({type: 'WorkerTest', timeStamp: 0})

        })
        .margin({top: 20})

      Text('Worker-dispatchEvent-message类型')
        .fontSize(20)
        .fontColor(Color.White)
        .borderRadius('12vp')
        .backgroundColor(Color.Blue)
        .padding(10)
        .stateStyles({
          focused: {
            .backgroundColor(Color.Green)
          },
          pressed: {
            .backgroundColor(Color.Green)
          },
          normal: {
            .backgroundColor(Color.Blue)
          }
        })
        .onClick(()=>{

          let tid = process.tid;

          console.log('当前进程ID ：' + tid)

          wk1.dispatchEvent({type: 'message', timeStamp: 0})

        })
        .margin({top: 20})

    }.width('100%').height('100%')
    .justifyContent(FlexAlign.Center)

  }

}

通过IDEWorker模板创模板下文件（参见：指导）
Worker.ts, Worker2.ts, Worker3.ts, Worker4.ts, Worker5.ts, Worker6.ts, Worker7.ts, Worker8.ts
这些文件内容完全一样，仅仅是名称不一样

import worker, { ThreadWorkerGlobalScope, MessageEvents, ErrorEvent } from '@ohos.worker';
import Logger from '../common/Logger';
import process from '@ohos.process';
import emitter from '@ohos.events.emitter'

var workerPort : ThreadWorkerGlobalScope = worker.workerPort;

/**
* Defines the event handler to be called when the worker thread receives a message sent by the host thread.
* The event handler is executed in the worker thread.
*
* @param e message data
*/
workerPort.onmessage = function(e : MessageEvents) {
  let tid = process.tid;

  Logger.d(tid + ' worker收到了消息 ： ' + JSON.stringify(e))

  setTimeout(()=>{
    workerPort.postMessage(
      {
        'no': (e.data.no),
        'threadID' : tid + '-' + e.data.threadID,
        'label': "worker",
      }
    )
  }, e.data.costtime)

  let eventData = {
    data: {
      'threadID' : tid + '-' + e.data.threadID,
      'from': 'emitter',
      "content": "c",
      "id": 1,
    }};
  let innerEvent = {
    eventId: 1847,
    priority: emitter.EventPriority.HIGH
  };
  emitter.emit(innerEvent, eventData);

}

/**
* Defines the event handler to be called when the worker receives a message that cannot be deserialized.
* The event handler is executed in the worker thread.
*
* @param e message data
*/
workerPort.onmessageerror = function(e : MessageEvents) {
  Logger.d(JSON.stringify(e))
}

/**
* Defines the event handler to be called when an exception occurs during worker execution.
* The event handler is executed in the worker thread.
*
* @param e error message
*/
workerPort.onerror = function(e : ErrorEvent) {
  Logger.d(JSON.stringify(e))
}

在Build-profile.json5需要添加如上TS

"buildOption": {
  "sourceOption": {
    "workers": [
      './src/main/ets/workers/worker.ts',
      './src/main/ets/workers/worker2.ts',
      './src/main/ets/workers/worker3.ts',
      './src/main/ets/workers/worker4.ts',
      './src/main/ets/workers/worker5.ts',
      './src/main/ets/workers/worker6.ts',
      './src/main/ets/workers/worker7.ts',
      './src/main/ets/workers/worker8.ts',
      './src/main/ets/workers/worker9.ts',
    ]
  }
}

HarmonyOS 消息传递

介绍

概况

开始

EventHub

样例

1. 订阅

2. 发送

3. 解除订阅

CommonEvent

1. 订阅

2. 发送

3. 解除订阅

Emitter

1. 订阅

2. 发送

3. 解除订阅

Worker

1. 订阅

2. 发送

a）从worker线程中发送

b) 从主线程中发送

3. 解除订阅

TaskTool 和 Notification

总结

实践代码效果

公共事件代码

线程代码