HarmonyOS 用calc设置宽度.width(calc(100% -30))，根据需要设置的margin做动态赋值

@Builder  
choiceLoginDeviceItem(item:LoginDeviceModel): void {  
    Row() {  
      if (this.isSelect) {  
        Image(item.selectIcon)  
          .height(15)  
          .margin({right:5})  
      }  
      LoginDeviceItem({  
        loginDevice:item,  
        logOut:false  
      })  
        .width(calc(100% - 30 - (this.isSelect ? 20 : 0)))  
    }  
    .margin({  
      left:15,  
      right:15,  
      bottom:10  
    })  
    .onClick(()=>{  
      this.singleChoiceSelectStateModify(item)  
    })  
  }