通过@H_403_2@stroyboard的运行时属性@H_403_2@runtime attribute可以对@H_403_2@Button设置圆角或者边框。@H_403_2@

1.@H_403_2@很多人都知道通常设置一个Button@H_403_2@或者其他UIIView@H_403_2@子类的圆角使用@H_403_2@

self.button.layer.cornerRadius = 10

这会用到layer@H_403_2@的图层属性来实现的，UIView@H_403_2@本身只是用来监听时间，而真正的现实内容的是layer@H_403_2@图层，这当然也包含动画的实现，比如我们对一个view@H_403_2@做的动画@H_403_2@

实际上也是对layer@H_403_2@做的动画@H_403_2@

2.@H_403_2@但是我们想知道如何通过xib @H_403_2@设置一个button@H_403_2@或者UIView@H_403_2@的圆角， @H_403_2@通过研究发现一种方法，这个方法就是runtime Attribute @H_403_2@运行时属性，也就是在运行时你设置这个属性才会起作用，这样体现了OC@H_403_2@语言的动态特性和运行时（runtime@H_403_2@）

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
    
        // Do any additional setup after loading the view,typically from a nib.
    }

    func test() {
        
        print([NSThread .isMainThread()] )
        
        let i: BooleanType = true
        
        while i {
            print("***")
        }
    }
    
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        prepareUI()
    }
    
    func prepareUI() {
        self.view.addSubview(button)
        
    }
    
    lazy var button :UIButton = {
       
        let button = UIButton(type: UIButtonType.Custom)
        button.frame = CGRect(x: 50,y: 50,width: 100,height: 100)
        button.backgroundColor = UIColor.orangeColor()
        button.layer.cornerRadius = 50;
        return button
    }()
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}