swift - 按下按钮后使用 case 语句检查值的状态

Question

    @IBAction func sortList(_ sender: Any) {
    var stateOfList = 0
    var sortedList = array
    switch stateOfList {
    case 0:
        sortedList = array.sorted { ($0.priceUsd!) > ($1.priceUsd!) }
        stateOfList = 1
    case 1:
        sortedList = array.sorted { ($0.priceUsd!) < ($1.priceUsd!) }
        stateOfList = 2
    case 2:
        sortedList = array.sorted { ($0.rank) < ($1.rank) }
        stateOfList = 0
    default:
        stateOfList = 0
    }


    array = sortedList
    tableView.reloadData()
    print(stateOfList)
}

我想在按下按钮后对数组进行排序并更改列表的状态。第二次按应按另一个方向对数组进行排序。但是编译器告诉我“永远不会被执行”。我在这里做错了什么？

Answer 1

使 var stateOfList 成为 View Controller 的实例属性以保存状态并在第二次按下时再次访问它。

var stateOfList = 0

你的函数会像

@IBAction func sortList(_ sender: Any) {
    var sortedList = array
    switch stateOfList {
    case 0:
        sortedList = array.sorted { ($0.priceUsd!) > ($1.priceUsd!) }
        stateOfList = 1
    case 1:
        sortedList = array.sorted { ($0.priceUsd!) < ($1.priceUsd!) }
        stateOfList = 2
    case 2:
        sortedList = array.sorted { ($0.rank) < ($1.rank) }
        stateOfList = 0
    default:
        stateOfList = 0
    }

    array = sortedList
    tableView.reloadData()
    print(stateOfList)
}