#鸿蒙通关秘籍#如何在鸿蒙开发中避免在主线程中执行耗时操作

在鸿蒙应用开发中，避免在主线程执行耗时操作可以有效提升应用的流畅性。采用多线程处理耗时任务，通过子线程处理如网络请求、文件读取等操作，然后在主线程中更新UI，能够减少主线程阻塞，避免应用卡顿。以下是如何实现的代码示例：

build() {
    Column({ space: 2 }) {
      WaterFlow({}) {
        LazyForEach(this.dataSource, (item: ModelDetailVO) => {
          FlowItem() {
            Column() {
              Image(item.url)
            }
          }
          .onAppear(() => {
            if (item.id + 10 === this.dataSource.totalCount()) {
              taskpoolExecute(this.dataSource.totalCount()).then((data: ModelDetailVO[]) => {
                for (let i = 0; i < data.length; i++) {
                  this.dataSource.addLastItem(data[i]);
                }
              })
            }
          })
        }, (item: string) => item)
      }
    }
  }
  
  async function taskpoolExecute(index: number): Promise<ModelDetailVO[]> {
    let task: taskpool.Task = new taskpool.Task(mockRequestData, index, getContext());
    return await taskpool.execute(task) as ModelDetailVO[];
  }

  @Concurrent
  async function mockRequestData(index: number, context: Context): Promise<ModelDetailVO[]> {
    let result: modelDetailDTO[] = [];
    await context.resourceManager.getRawFileContent("data.json").then((data: Uint8Array) => {
      let jsonData = buffer.from(data).toString();
      let res: responseData = JSON.parse(jsonData);
      result = res.data;
    })
    return transArrayDTO2VO(result, index);
  }

  @Sendable
  class ModelDetailVO {
    id: number = 0;
    name: string = "";
    url: string = "";
  }