ArkTS如何自定义加载，设置字体fontFamily

import font from '@ohos.font';  
  
@Entry  
@Component  
struct FontExample {  
  @State message: string = '世界'  
  
  aboutToAppear() {  
    // familyName和familySrc都支持string  
    font.registerFont({  
      familyName: 'medium',  
      familySrc: '/font/medium.ttf' // font文件与pages目录同级  
    })  
  }  
  
  build() {  
    Column() {  
      Text(this.message)  
        .align(Alignment.Center)  
        .fontSize(20)  
        .fontFamily('medium') // medium：注册自定义字体的名字  
        .height('100%')  
    }.width('100%')  
  }  
}