Question

当我从swift 2转换为swift 3时我所面临的错误是＆＃34;对成员下标的模糊引用＆＃34;

以下是我的代码：

class KeyValueChange {

    fileprivate let change: [String : AnyObject]

    init(change: [String : AnyObject]) {
        self.change = change
    }

    var kind: NSKeyValueChange? {
        guard let value = change[NSKeyValueChangeKey.kindKey] as? NSNumber else {
            return nil
        }

        return NSKeyValueChange(rawValue: value.uintValue)
    }

    var indexSet: IndexSet? {
        return change[NSKeyValueChangeKey.indexesKey] as? IndexSet
    }

    var new: AnyObject? {
        return change[NSKeyValueChangeKey.newKey]
    }

}

请详细说明，因为在很多地方都会遇到同样的错误

提前致谢

Answer 1

在Swift3中，KVO方法observeValue(forKeyPath:of:change:context:)为[NSKeyValueChangeKey : Any]?参数传递change。如果您想使用KeyValueChange课程，您可以更好地适应变化：

class KeyValueChange {

    private let change: [NSKeyValueChangeKey : Any]

    init(change: [NSKeyValueChangeKey : Any]) {
        self.change = change
    }

    var kind: NSKeyValueChange? {

        guard let value = change[NSKeyValueChangeKey.kindKey] as? NSNumber else {
            return nil
        }

        return NSKeyValueChange(rawValue: value.uintValue)
    }

    var indexSet: IndexSet? {
        return change[NSKeyValueChangeKey.indexesKey] as? IndexSet
    }

    var new: Any? {
        return change[NSKeyValueChangeKey.newKey]
    }

}

NSKeyValueChangeKey对成员下标的模糊引用

1 个答案: