Swift 成员变量的get/set

import UIKit

class Question: NSObject {

var answer: String!
var icon: String!
var title: String!
var options: [String]!

// 自定义 get、set
var image: UIImage {
get {
return UIImage(named: self.icon)!
}

set {
self.image = newValue
}
}

// 懒加载
lazy private var questions: [AnyObject] = {
// 例如：
return ["quetion1", "quetion2", "quetion3"]
}()

// 指定初始化
init(data: [String : AnyObject]) {
super.init()

self.setValuesForKeysWithDictionary(data)
}

}