Question

我有一个班级：

class WeaponItems {

var name: String
var index: Int
var price: Int
var weaponPower: Int = 0
var attackSpeed: Double = 0
var criticalChance: Double = 0
var criticalDamage: Double = 0

init(name: String, index: Int, price: Int){
    self.name = name
    self.index = index
    self.price = price
}

var weaponBlade = WeaponItems(name: "Weapon Blade", index: 0, price: 300)
weaponBlade.weaponPower = 15
// Error: expected declaration

var swiftShooter = WeaponItems(name: "Swift Shooter", index: 1, price: 300)
swiftShooter.attackSpeed = 0.2
// Error: expected declaration

var minionsFoot = WeaponItems(name: "Minions Foot", index: 3, price: 300)
minionsFoot.criticalChance = 0.1
minionsFoot.criticalDamage = 0.1
// Error: expected declaration

}

我需要为每个项目设置weaponPower attackSpeed ...，这样做会出错。

我发现答案说你必须使用一个函数来修改实例的值，但我觉得这会使代码变得复杂，我该怎么设置它的值呢？

使用函数的关注点是它将实例创建和值设置过程分开，使代码更难维护。

Answer 1

你应该为类

中的所有weaponItem添加属性

那么你的类实现应该是这样的

class WeaponItems {

    var name: String
    var index: Int
    var price: Int
    var weaponPower: Int = 0
    var attackSpeed: Double = 0
    var criticalChance: Double = 0
    var criticalDamage: Double = 0

    var weaponBlade:WeaponItems{

        get {
            let tempWeaponBlade = WeaponItems(name: "Weapon Blade", index: 0, price: 300)
            tempWeaponBlade.weaponPower = 15
            return tempWeaponBlade
        }
    }

    var swiftShooter:WeaponItems{

        get {
            let tempSwiftShooter = WeaponItems(name: "Swift Shooter", index: 1, price: 300)
            tempSwiftShooter.attackSpeed = 0.2
            return tempSwiftShooter
        }
    }

    var minionsFoot:WeaponItems{

        get {
            let tempMinionsFoot = WeaponItems(name: "Minions Foot", index: 3, price: 300)
            tempMinionsFoot.criticalChance = 0.1
            tempMinionsFoot.criticalDamage = 0.1
            return tempMinionsFoot 
        }
    }


    init(name: String, index: Int, price: Int){
        self.name = name
        self.index = index
        self.price = price
    }

}

Answer 2

在您的情况下，如果代码会编译，要使用预先创建的weaponBlade，您必须创建两个WeaponItems实例，如下所示：

let balde = WeaponItems(name: "", index: 0, price: 0).weaponBlade

这不是最好的解决方案，即使在你的情况下根本不编译（你可以阅读@ gnasher729的评论来理解原因）。

我建议你创建它们的静态实例

extension WeaponItems {
    static var Blade: WeaponItems {
        get {
            let blade = WeaponItems(name: "The name", index: 1, price: 300)
            blade.weaponPower = 15
            return blade
        }
    }
}

现在您可以通过键入WeaponItems.Blade来使用该刀片，或者如果它类型很容易推断如下：

let blade: WeaponItems = .Blade

Answer 3

如果您希望拥有默认属性值，您还希望在创建实例时自定义，我建议您在初始化程序中使用default parameter values。这将允许您使用初始化时已知的实际属性值创建WeaponItems类的新实例，而不是在之后立即更改的某些默认值。

我也非常同意with Luca D'Alberti - 您不需要预先设定的武器＆＃39;成为实例属性。因为他们不依赖于任何实例状态，或者对于给定实例是唯一的 - 它们应该是static。

例如：

class Weapon {

    static var blade : Weapon {
        return Weapon(name: "Blade", index: 0, price: 300, power: 15)
    }

    static var swiftShooter : Weapon {
        return Weapon(name: "Swift Shooter", index: 1, price: 300, attackSpeed: 0.2)
    }

    static var minionsFoot : Weapon {
        return Weapon(name: "Minions Foot", index: 3, price: 300, criticalChance: 0.1, criticalDamage: 0.1)
    }

    var name: String
    var index: Int
    var price: Int
    var power: Int
    var attackSpeed: Double
    var criticalChance: Double
    var criticalDamage: Double

    init(name: String, index: Int, price: Int,
         power: Int = 0, attackSpeed: Double = 0,
         criticalChance: Double = 0, criticalDamage: Double = 0) {

        self.name = name
        self.index = index
        self.price = price
        self.power = power
        self.attackSpeed = attackSpeed
        self.criticalChance = criticalChance
        self.criticalDamage = criticalDamage
    }
}

的

let blade = Weapon.blade
let swiftShooter : Weapon = .swiftShooter

Answer 4

您可以尝试使用以下代码。

lazy var weaponBlade:WeaponItems = {

        let _weaponBlade = WeaponItems(name: "Weapon Blade", index: 0, price: 300)
        _weaponBlade.weaponPower = 15
        return _weaponBlade
    }()

请参阅此link以了解有关延迟变量的更多信息。

如何在不使用函数的情况下修改实例值？

4 个答案: