列出 Swift2 中类的所有“动态”变量

Question

我正在编写一个实现KVO 的基类，我想推断该类的dynamic 属性的名称。例如：

class BaseClass {
  func beginObserving() {
    // What are the dynamic attributes to observe?
    // In the case of "SubClass" below, it should be ["name"]
    let attributes = ???
    for attribute in attributes {
      self.addObserver(self, forKeyPath: attribute, options: [.New, .Old], context: &KVOContext)
    }
  }
}

class SubClass : BaseClass {
  dynamic var name: String!
}

List of class's properties in swift 解释了如何使用Mirror（反射）来执行此操作，但它似乎不适用于dynamic vars（即，如果我删除了dynamic 关键字，则链接代码将适用于这种情况)。

Answer 1

您可以使用标准的<objc/runtime.h> 函数：

class MyObject {
    dynamic var identifier = 0

    func dynamicProperties() -> [String] {
        var dynamicProperties = [String]()

        var propertyCount = UInt32(0)
        let properties = class_copyPropertyList(object_getClass(self), &propertyCount)
        for var i = 0; i < Int(propertyCount); i++ {
            let property = properties[i]
            let propertyName = property_getName(property)
            dynamicProperties.append(String(CString: propertyName, encoding: NSUTF8StringEncoding)!)
        }
        free(properties)

        return dynamicProperties
    }
}

--

如果您希望子类不仅显示其属性，还显示其超类的属性，您可以执行以下操作：

class BaseClass {
    dynamic var identifier = 0

    func dynamicProperties() -> [String] {
        var dynamicProperties = [String]()

        var propertyCount = UInt32(0)
        let properties = class_copyPropertyList(object_getClass(self), &propertyCount)
        for var i = 0; i < Int(propertyCount); i++ {
            let property = properties[i]
            let propertyName = property_getName(property)
            dynamicProperties.append(String(CString: propertyName, encoding: NSUTF8StringEncoding)!)
        }
        free(properties)

        return dynamicProperties
    }
}

class SubClass : BaseClass {
    dynamic var name: String!

    override func dynamicProperties() -> [String] {
        var dynamicProperties = super.dynamicProperties()

        var propertyCount = UInt32(0)
        let properties = class_copyPropertyList(object_getClass(self), &propertyCount)
        for var i = 0; i < Int(propertyCount); i++ {
            let property = properties[i]
            let propertyName = property_getName(property)
            dynamicProperties.append(String(CString: propertyName, encoding: NSUTF8StringEncoding)!)
        }
        free(properties)

        return dynamicProperties
    }

}