在Harmony NEXT应用中，如何实现应用的后台运行和通知推送？

Question

在Harmony NEXT应用中，如何实现应用的后台运行和通知推送？
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Answer 1

后台运行具体可参考代码：

// BackTaskImplement/entry/src/main/ets/viewModel/ShortTermTaskModel.ets
// Apply front - and back-end status monitoring
subscribeStateChange() {
  let that = this;
  // Gets applicationContext
  let applicationContext = this.context.getApplicationContext();
  let applicationStateChangeCallback: ApplicationStateChangeCallback = {
    onApplicationForeground() {
      hilog.info(0x0000, TAG, 'applicationStateChangeCallback onApplicationForeground');
    },
    onApplicationBackground() {
      hilog.info(0x0000, TAG, 'applicationStateChangeCallback onApplicationBackground');
      // Apply for short-time tasks when the application changes from foreground to background
      that.suspendTaskInfo = SuspendTaskUtils.requestSuspendDelay('Suspend Task');
      hilog.info(0x0000, TAG,
        `requestSuspendDelay, id:${that.suspendTaskInfo.id}, delayTime:${that.suspendTaskInfo.delayTime}`);
    }
  }
  try {
    // Registers the background and pre - application status monitoring through applicationContext
    applicationContext.on('applicationStateChange', applicationStateChangeCallback);
  } catch (paramError) {
    hilog.error(0x0000, TAG,
      `error: ${(paramError as BusinessError).code}, ${(paramError as BusinessError).message}`);
  }
}

消息通知可参考代码：

// BackTaskImplement/entry/src/main/ets/viewModel/ShortTermTaskModel.ets
// Apply front - and back-end status monitoring
subscribeStateChange() {
  let that = this;
  // Gets applicationContext
  let applicationContext = this.context.getApplicationContext();
  let applicationStateChangeCallback: ApplicationStateChangeCallback = {
    onApplicationForeground() {
      hilog.info(0x0000, TAG, 'applicationStateChangeCallback onApplicationForeground');
    },
    onApplicationBackground() {
      hilog.info(0x0000, TAG, 'applicationStateChangeCallback onApplicationBackground');
      // Apply for short-time tasks when the application changes from foreground to background
      that.suspendTaskInfo = SuspendTaskUtils.requestSuspendDelay('Suspend Task');
      hilog.info(0x0000, TAG,
        `requestSuspendDelay, id:${that.suspendTaskInfo.id}, delayTime:${that.suspendTaskInfo.delayTime}`);
    }
  }
  try {
    // Registers the background and pre - application status monitoring through applicationContext
    applicationContext.on('applicationStateChange', applicationStateChangeCallback);
  } catch (paramError) {
    hilog.error(0x0000, TAG,
      `error: ${(paramError as BusinessError).code}, ${(paramError as BusinessError).message}`);
  }
}