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散列==方法不检测两个对象swift之间的差异

equatable hashable uicollectionview swift ios

0

Alk · 技术社区 · 5 年前

我实施了以下课程:

    class Table : Hashable {

    var uid : Int
    var timeRemaining : Int?
    var currentPrice : Double?
    var hashValue: Int {
        return uid.hashValue
    }

    static func ==(lhs: Table, rhs: Table) -> Bool {
        return lhs.uid == rhs.uid && lhs.timeRemaining == rhs.timeRemaining && lhs.currentPrice == rhs.currentPrice
    }

    init (uid: Int, timeRemaining: Int?, currentPrice: Double?) {
        self.uid = uid
        self.timeRemaining = timeRemaining
        self.currentPrice = currentPrice
    }
}

private var tables = [Table]()

func updateAuctions() {
    let oldItems = tables
    let newItems = oldItems
    for table in newItems {
        let oldPrice = table.currentPrice!
        let timeRemaining = table.timeRemaining!
        table.currentPrice = oldPrice + 0.50
        table.timeRemaining = timeRemaining - 1
    }
    let changes = diff(old: oldItems, new: newItems)

    collectionView.reload(changes: changes, section: 0) { (complete) in
        if (complete) {
            self.tables = newItems
        }
    }
}

这使用了下面描述的DeepDiff框架: https://github.com/onmyway133/DeepDiff

我的目标是刷新 UICollectionView 随着对 tables 数组,但是框架没有检测到任何更改,即使 == timeRemaining 和 currentPrice

1 回复 | 直到 5 年前

1

Bill 5 年前

让newItems=旧项

因为两个数组都包含对象实例,它们不就指向相同的对象吗?所以当你迭代 newItems oldItems 我也是。可以通过在 for

也许你可以试试下面的方法?

func updateAuctions() {
    let oldItems = tables
    let newItems = [Table]()
    for item in oldItems {
        newItems.append(Table(uid: item.uid, timeRemaining: item.timeRemaining! - 1, currentPrice: item.currentPrice! + 0.50))
    }
    let changes = diff(old: oldItems, new: newItems)

    collectionView.reload(changes: changes, section: 0) { (complete) in
        if (complete) {
            self.tables = newItems
        }
    }
}