HarmonyOS 数据刷新问题？

Question

使用了这个三方库ohpm install @ohos/liveeventbus。

使用代码如下：发现 @State eventBus:不能更新UI。

const KEY_TEST_CLOSE_ALL_PAGE = "key_test_close_all_page";

@Entry
@Component
struct EventBusPage {
  mLifecycle: Lifecycle = new Lifecycle(MState.STARTED);
  @State eventBus: boolean = false;

  aboutToAppear(): void {
    //创建生命周期感知对象
    this.mLifecycle = new Lifecycle(MState.STARTED)

    //订阅消息
    LiveEventBus
      .get<boolean>(KEY_TEST_CLOSE_ALL_PAGE)
      .observe(this, {
        onChanged(b: boolean) {
          this.eventBus = b;
        }
      });
  }

  build() {
    Row() {
      Column() {
        Text('LiveEventBus Demo' + this.eventBus)
          .fontSize(30)
          .fontWeight(FontWeight.Bold)
      }.onClick((e) => {
        //发送消息
        LiveEventBus.get(KEY_TEST_CLOSE_ALL_PAGE).post( !this.eventBus);
      })
      .width('100%')
    }
    .height('100%')
  }

  //生命周期感知对象
  getLifecycle(): Lifecycle {
    return this.mLifecycle
  }
}

Answer 1

eventBus的使用请参考文档：https://gitee.com/openharmony-sig/LiveEventBus，demo中onchanged方法中的this对应的不是页面的this，所以不会发生变化可以参考此demo：

//引入
import { LiveEventBus,Lifecycle,MState } from '@ohos/liveeventbus'
const KEY_TEST_CLOSE_ALL_PAGE = "key_test_close_all_page";

@Entry
@Component
struct EventBusPage {
  mLifecycle: Lifecycle = new Lifecycle(MState.STARTED);
  @State eventBus: boolean = false;

  aboutToAppear(): void {
    //创建生命周期感知对象
    this.mLifecycle = new Lifecycle(MState.STARTED)

    //订阅消息
    LiveEventBus
      .get<boolean>(KEY_TEST_CLOSE_ALL_PAGE)
      .observe(this, {
        onChanged: (b: boolean) => {
          this.eventBus = b;
        }
      });
  }

  build() {
    Row() {
      Column() {
        Text('LiveEventBus Demo' + this.eventBus)
          .fontSize(30)
          .fontWeight(FontWeight.Bold)
      }.onClick((e) => {
        //发送消息
        LiveEventBus.get(KEY_TEST_CLOSE_ALL_PAGE).post( !this.eventBus);
      })
      .width('100%')
    }
    .height('100%')
  }

  //生命周期感知对象
  getLifecycle(): Lifecycle {
    return this.mLifecycle
  }
}