HasAssociatedObjects 2.0.0

HasAssociatedObjects 2.0.0

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语言语言 SwiftSwift
许可证 MIT
发布最新发布2017年10月
SwiftSwift 版本3.0
SPM支持 SPM✗

由 tokorom 维护。

HasAssociatedObjects 2.0.0

  • 作者：
  • tokorom

HasAssociatedObjects

==================




我们可以向 Swift 扩展添加一些存储对象

问题：我们能否向扩展中添加存储属性？

答案：不可以，但我们可以使用关联对象。

简单用法

extension UIViewController: HasAssociatedObjects {

    // new stored property
    var storedString: String? {
        get {
            return associatedObjects.value as? String
        }
        set {
            associatedObjects.value = newValue
        }
    }

}

其他用法

多个存储属性

extension UIViewController: HasAssociatedObjects {

    var storedString: String? {
        get {
            return associatedObjects["STRING"] as? String
        }
        set {
            associatedObjects["STRING"] = newValue ?? ""
        }
    }

    var storedInt: Int {
        get {
            guard let value = associatedObjects["INT"] as? Int else {
                return 0 //< default value
            }
            return value
        }
        set {
            associatedObjects["INT"] = newValue
        }
    }

}

直接使用

extension Subject: HasAssociatedObjects {
}

subject.associatedObjects.value = 10

let storedValue = subject.associatedObjects.value as? Int
XCTAssertEqual(10, storedValue)

主题不是AnyObject

// subject is struct
struct AnySubject {
    let identifier: Int
}

// a appropriate property that can be cleaned
var propertyOfSomeone: [Int: AssociatedObjects] = [:]

// You can customize `associatedObjects`
extension AnySubject: HasAssociatedObjects {
    var associatedObjects: AssociatedObjects {
        guard let associatedObjects = propertyOfSomeone[hashValue] else {
            let associatedObjects = AssociatedObjects()
            propertyOfSomeone[hashValue] = associatedObjects
            return associatedObjects
        }
        return associatedObjects
    }
}

extension AnySubject: Hashable {
    var hashValue: Int {
        return identifier
    }

    static func == (lhs: AnySubject, rhs: AnySubject) -> Bool {
        return lhs.hashValue == rhs.hashValue
    }
}

安装