Ios 如何修复错误：二进制运算符'=='；无法应用于类型为'；NSExpression.ExpressionType'；和'_'；

当我遇到一个表示

.KeyPathExpressionType

我说不出是什么原因

.

在

指的是位于

.

当我搜索Google并堆叠“KeyPathExpressionType”时，我什么也找不到。对我来说也是

.ConstantValueExpressionType

我什么也没找到

每一项都是平等比较

comparison.leftExpression.expressionType == .KeyPathExpressionType

及

在下面的代码中，生成一条错误消息：

二进制运算符“==”不能应用于“NSExpression.ExpressionType”和“\u1”类型的操作数

当我替换时，错误会消失

comparison.leftExpression.expressionType == .KeyPathExpressionType

与

及

与

---

这是正确的吗？有人能告诉我这个问题的答案吗？

代码已经过时了Swift 2代码

将

.KeyPathExpressionType

替换为

.keyPath

并将

替换为
.ConstantValueExpressionType

类型是
NSExpression.ExpressionType
，请阅读不确定，但看起来像
。KeyPathExpressionType
是
的旧名称。keyPath
。你能试试比较一下吗？leftExpression.expressionType==.keyPath

？是的。这很有效。我实际上输入了“NSExpression.ExpressionType.keyPath”，我使用了“NSExpression.ExpressionType.keyPath”和“NSExpression.ExpressionType.constantValue”，它就工作了。谢谢。您可以省略

NSExpression.ExpressionType

，编译器将推断类型。

comparison.rightExpression.expressionType == .ConstantValueExpressionType

extension NSPredicate {

    /**
        Parses the predicate and attempts to generate a characteristic-value `HomeKitConditionType`.

        - returns:  An optional characteristic-value tuple.
    */
    private func characteristic() -> HomeKitConditionType? {
        guard let predicate = self as? NSCompoundPredicate else { return nil }
        guard let subpredicates = predicate.subpredicates as? [NSPredicate] else { return nil }
        guard subpredicates.count == 2 else { return nil }

        var characteristicPredicate: NSComparisonPredicate? = nil
        var valuePredicate: NSComparisonPredicate? = nil

        for subpredicate in subpredicates {
            if let comparison = subpredicate as? NSComparisonPredicate, comparison.leftExpression.expressionType == .KeyPathExpressionType && comparison.rightExpression.expressionType == .ConstantValueExpressionType {
                switch comparison.leftExpression.keyPath {
                    case HMCharacteristicKeyPath:
                        characteristicPredicate = comparison

                    case HMCharacteristicValueKeyPath:
                        valuePredicate = comparison

                    default:
                        break
                }
            }
        }

        if let characteristic = characteristicPredicate?.rightExpression.constantValue as? HMCharacteristic,
            characteristicValue = valuePredicate?.rightExpression.constantValue as? NSCopying {
                return .Characteristic(characteristic, characteristicValue)
        }
        return nil
    }

comparison.leftExpression.expressionType == .KeyPathExpressionType

comparison.leftExpression.expressionType.rawValue == NSExpression.ExpressionType.keyPath.rawValue

comparison.rightExpression.expressionType == .ConstantValueExpressionType

comparison.rightExpression.expressionType.rawValue == NSExpression.ExpressionType.constantValue.rawValue