我有关HashMap的Java代码有什么问题？

Question

这是错误通知：

  

Library.java:13：错误：找不到符号         对于（String book：library.KeySet（））{                                   ^符号：方法KeySet（）位置：HashMap 1类型的变量库错误

这是代码：

import UIKit

public class EngineConfigurationA: OptionSet {

    public static let enableSun   = EngineConfigurationA(rawValue: 1 << 0)
    public static let enableFloor = EngineConfigurationA(rawValue: 1 << 1)

    public var rawValue: Int

    required public init(rawValue: RawValue) {
        self.rawValue = rawValue
    }

}


public class EngineConfigurationB: EngineConfigurationA {

    public static let enableWorldTracking              = EngineConfigurationB(rawValue: 1 << 2)
    public static let enableEnvironmentLightEstimation = EngineConfigurationB(rawValue: 1 << 3)
    public static let enableFloorLevelDetection        = EngineConfigurationB(rawValue: 1 << 4)

}

let optionsB: EngineConfigurationB = [EngineConfigurationB.enableWorldTracking, EngineConfigurationA.enableSun]

let contains = optionsB.contains(EngineConfigurationB.enableWorldTracking)

我想知道这段代码怎么了？特别是13号线？谢谢。

Answer 1

有一个错字，请使用keySet()代替KeySet()

 for (String book : library.keySet()) { }