HarmonyOS 没有全局的api loading动画

import { changeDialogBuilder, MyShowTest } from '../common/HttpUtils'  
import {customDialogBuilder} from './testProm'  
let myShowTest = new MyShowTest()  
@Entry  
@Component  
struct Index {  
  @State message: string = 'Hello World'  
  onPageShow(): void {  
    changeDialogBuilder(customDialogBuilder.bind(this))  
  }  
  build() {  
    Row() {  
      Column() {  
        Text(this.message)  
          .fontSize(50)  
          .fontWeight(FontWeight.Bold)  
          .onClick(() => {  
            myShowTest.showTest()  
          })  
      }  
      .width('100%')  
    }  
    .height('100%')  
  }  
}

@Builder  
export function customDialogBuilder() {  
  Column() {  
    Text('正在加载中').fontSize(16)  
  }.height(100).width(100)  
}

import promptAction from '@ohos.promptAction'  
let myDialogBuilder: CustomBuilder;  
let customDialogId: number = 0  
export function changeDialogBuilder(builder: CustomBuilder) {  
  myDialogBuilder = builder  
}  
export class MyShowTest {  
  showTest() {  
    if (myDialogBuilder === undefined) {  
      return  
    }  
    promptAction.openCustomDialog({  
      builder: myDialogBuilder,  
      alignment: DialogAlignment.Center,  
    }).then((dialogId: number) => {  
      customDialogId = dialogId  
    })  
    setTimeout(() => {  
      promptAction.closeCustomDialog(customDialogId)  
    }, 2000)  
  }  
}