在使用 TaskPool 时,执行的并发函数需要使用该装饰器修饰,否则无法通过相关校验。

说明:
从API version 9开始,该装饰器支持在ArkTS卡片中使用。

装饰器说明 

说明:
并发函数中返回Promise的表现需关注,其中并发同步函数会处理返回该Promise并返回结果。 

示例:

import taskpool from '@ohos.taskpool';

@Concurrent
function testPromise(args1: number, args2: number): Promise<number> {
  return new Promise<number>((testFuncA, testFuncB)=>{
    testFuncA(args1 + args2);
  });
}

@Concurrent
async function testPromise1(args1: number, args2: number): Promise<number> {
  return new Promise<number>((testFuncA, testFuncB)=>{
    testFuncA(args1 + args2);
  });
}

@Concurrent
async function testPromise2(args1: number, args2: number): Promise<number> {
  return await new Promise<number>((testFuncA, testFuncB)=>{
    testFuncA(args1 + args2)
  });
}

@Concurrent
function testPromise3() {
  return Promise.resolve(1);
}

@Concurrent
async function testPromise4(): Promise<number> {
  return 1;
}

@Concurrent
async function testPromise5(): Promise<string> {
  return await new Promise((resolve) => {
    setTimeout(()=>{
      resolve("Promise setTimeout after resolve");
    }, 1000)
  });
}

async function testConcurrentFunc() {
  let task1: taskpool.Task = new taskpool.Task(testPromise, 1, 2);
  let task2: taskpool.Task = new taskpool.Task(testPromise1, 1, 2);
  let task3: taskpool.Task = new taskpool.Task(testPromise2, 1, 2);
  let task4: taskpool.Task = new taskpool.Task(testPromise3);
  let task5: taskpool.Task = new taskpool.Task(testPromise4);
  let task6: taskpool.Task = new taskpool.Task(testPromise5);

  taskpool.execute(task1).then((d:object)=>{
    console.info("task1 res is: " + d)
  }).catch((e:object)=>{
    console.info("task1 catch e: " + e)
  })
  taskpool.execute(task2).then((d:object)=>{
    console.info("task2 res is: " + d)
  }).catch((e:object)=>{
    console.info("task2 catch e: " + e)
  })
  taskpool.execute(task3).then((d:object)=>{
    console.info("task3 res is: " + d)
  }).catch((e:object)=>{
    console.info("task3 catch e: " + e)
  })
  taskpool.execute(task4).then((d:object)=>{
    console.info("task4 res is: " + d)
  }).catch((e:object)=>{
    console.info("task4 catch e: " + e)
  })
  taskpool.execute(task5).then((d:object)=>{
    console.info("task5 res is: " + d)
  }).catch((e:object)=>{
    console.info("task5 catch e: " + e)
  })
  taskpool.execute(task6).then((d:object)=>{
    console.info("task6 res is: " + d)
  }).catch((e:object)=>{
    console.info("task6 catch e: " + e)
  })
}

testConcurrentFunc();

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输出结果如下所示:

task1 res is: 3
task2 catch e: Error: Can't return Promise in pending state
task3 res is: 3
task4 res is: 1
task5 res is: 1
task6 res is: Promise setTimeout after resolve

说明:
并发异步方法中如果使用Promise,建议搭配await使用捕获Promise中可能发生的异常。推荐使用示例如下。

示例:

@Concurrent
async function testPromiseError() {
  await new Promise<number>((resolve, reject) => {
    resolve(1);
  }).then(()=>{
    throw new Error("testPromise Error");
  })
}

@Concurrent
async function testPromiseError1() {
  await new Promise<string>((resolve, reject) => {
    reject("testPromiseError1 Error msg");
  })
}

@Concurrent
function testPromiseError2() {
  return new Promise<string>((resolve, reject) => {
    reject("testPromiseError2 Error msg");
  })
}

async function testConcurrentFunc() {
  let task1: taskpool.Task = new taskpool.Task(testPromiseError);
  let task2: taskpool.Task = new taskpool.Task(testPromiseError1);
  let task3: taskpool.Task = new taskpool.Task(testPromiseError2);

  taskpool.execute(task1).then((d:object)=>{
    console.info("task1 res is: " + d)
  }).catch((e:object)=>{
    console.info("task1 catch e: " + e)
  })
  taskpool.execute(task2).then((d:object)=>{
    console.info("task2 res is: " + d)
  }).catch((e:object)=>{
    console.info("task2 catch e: " + e)
  })
  taskpool.execute(task3).then((d:object)=>{
    console.info("task3 res is: " + d)
  }).catch((e:object)=>{
    console.info("task3 catch e: " + e)
  })
}

testConcurrentFunc()

输出结果如下所示:

task1 catch e: Error: testPromise Error
task2 catch e: testPromiseError1 Error msg
task3 catch e: testPromiseError2 Error msg

装饰器使用示例

import taskpool from '@ohos.taskpool';

@Concurrent
function add(num1: number, num2: number): number {
  return num1 + num2;
}

async function ConcurrentFunc(): Promise<void> {
  try {
    let task: taskpool.Task = new taskpool.Task(add, 1, 2);
    console.info("taskpool res is: " + await taskpool.execute(task));
  } catch (e) {
    console.error("taskpool execute error is: " + e);
  }
}

@Entry
@Component
struct Index {
  @State message: string = 'Hello World'

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            ConcurrentFunc();
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}
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