Question

fun membershipSelected(membershipSelected: List<MemberShipType>) = apply { this.membershipSelected= membershipSelected}


object GOLD: MemberShipType("Gold"), IRateOption{}

object BRONZE: MemberShipType("Bronze"){}

在Kotlin中，如何限制membershipSelected仅是实现MembershipTypes接口的IRateOption？

例如，古铜色没有实现IRateOption，但是GOLD却实现了GOLD，因此可以选择membershipType

Answer 1

您需要使用带有Sub Main() Call ColorCodeTextInCell(ActiveSheet, "[B]", RGB(20,100,255)) End Sub Function ColorCodeTextInCell(WS As Worksheet, sText As String, Optional iColor As Long = vbRed) Dim bNewInstanceFound As Boolean Dim iStart As Integer Dim cell As Range bNewInstanceFound = True For Each cell In WS.UsedRange.Cells iStart = 1 Do While bNewInstanceFound = True Set cell = WS.Range("A1") iStart = InStr(iStart, cell.Value, sText) If iStart > 0 Then cell.Characters(iStart, Len(sText)).Font.Color = iColor iStart = iStart + Len(sText) Else bNewInstanceFound = False End If Loop Next cell End Function子句的泛型，例如documented in the Kotlin manual。对于您的用例，它看起来像这样：

where

或者，使用简写语法：

fun <T> membershipSelected(membershipSelected: List<T>): ReturnType
    where T : MembershipType,
          T : IRateOption {
    // function body
}

编辑：仅当参数中的所有项目均为同一类型时，此解决方案才有效。这意味着您将无法使用两个单独的类/对象，它们是fun <T> membershipSelected(membershipSelected: List<T>) where T : MembershipType, T : IRateOption = // function body和MembershipType的子类型。如果您需要这种行为，建议您创建一个开放或抽象类，如下所示：

IRateOption

Kotlin中的泛型-实现接口限制的类型

1 个答案: