我有一个协议叫做Parameter
: 有没有办法隐藏Swift Struct的默认初始化程序?
protocol Parameter {
var name: String { get }
var unit: Unit? { get }
var value: Double { get }
init(name: String, unit: Unit?, value: Double)
}
我也有16层结构符合Parameter
:
struct Calcium: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Calcium", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Alkalinity: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Alkalinity", unit: Unit? = Unit(symbol: "ppm CaCO3"), value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Salinity: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Salinity", unit: Unit? = Unit(symbol: "SG"), value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Temperature: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Temperature", unit: Unit? = UnitTemperature.fahrenheit, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct PH: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "pH", unit: Unit? = nil, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Magnesium: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Magnesium", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Phosphate: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Phosphate", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Ammonia: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Ammonia", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Silica: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Silica", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Iodine: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Iodine", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Nitrate: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Nitrate", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Nitrite: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Nitrite", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Strontium: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Strontium", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct ORP: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "ORP", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Boron: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Boron", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
struct Iron: Parameter {
var name: String
var unit: Unit?
var value: Double
init(name: String = "Iron", unit: Unit? = UnitDispersion.partsPerMillion, value: Double) {
self.name = name
self.unit = unit
self.value = value
}
}
正如你所看到的,所有的结构都实现了相同的初始化。
let calcium = Calcium(value: Double)
我还可以得到由结构创建的默认初始值:
let calcium = Calcium(name: String, unit: Unit?, value: Double)
在初始化,我有两个由
Parameter
协议,这给了我下面的初始化需要三个参数提供默认值
当我创建结构体的实例时,两个初始化符都出现在Xcode的代码完成弹出窗口中。但是,我不希望name
和unit
参数能够与初始值设定项中提供的默认值不同。我还尝试为name
和unit
属性指定默认值,其中它们在结构中声明,但在Parameter
协议所需的初始化程序之外声明。
有没有办法通过为name
和unit
参数提供默认值,只需要要提供的value
参数,而不必在Xcode的代码完成弹出默认初始化显示初始化结构?
在Xcode的代码完成弹出窗口中出现的两个初始值设定项唯一的问题是,我不希望别人创建结构并提供值,而不是我在Parameter
协议所要求的初始值设定项中提供的值。
我意识到我可以通过一个类来实现,但我试图通过面向协议的编程和使用结构来实现我的想法。