ios自带自动布局太过繁琐，所以一直采用第三方框架Snapkit的自动布局。NSLayoutAnchor(ios9.0)虽然优化了自动布局，但是感觉还是不够用啊，不知道苹果后续还会不会继续优化。

NSLayoutAnchor与Snapkit简易自动布局与动画对比:

Snapkit写法

  yellowView = UIView()
  yellowView.backgroundColor = UIColor.yellowColor()
  view.addSubview(yellowView)
  yellowView.snp_makeConstraints { (make) in
        make.left.equalTo(self.view).offset(20)
        make.top.equalTo(self.view).offset(20)
        make.width.height.equalTo(100)
   }
        
        redView = UIView()
        redView.backgroundColor = UIColor.redColor()
        view.addSubview(redView)
        redView.snp_makeConstraints { (make) in
            make.left.equalTo(yellowView.snp_right).offset(80)
            make.top.equalTo(yellowView.snp_top)
            make.height.width.equalTo(yellowView)
        }

NSLayoutAnchor写法

orangeView = UIView()
        orangeView.backgroundColor = UIColor.orangeColor()
        view.addSubview(orangeView)
        orangeView.translatesAutoresizingMaskIntoConstraints = false
        orangeView.topAnchor.constraintEqualToAnchor(yellowView.topAnchor, constant: 100).active = true
        orangeView.leftAnchor.constraintEqualToAnchor(yellowView.leftAnchor).active = true
        orangeView.widthAnchor.constraintEqualToAnchor(yellowView.widthAnchor, multiplier: 1, constant: 0).active = true
        orangeView.heightAnchor.constraintEqualToAnchor(yellowView.heightAnchor, multiplier: 1, constant: 0).active = true
        
        greenView = UIView()
        greenView.backgroundColor = UIColor.greenColor()
        view.addSubview(greenView)
        greenView.translatesAutoresizingMaskIntoConstraints = false
        greenView.topAnchor.constraintEqualToAnchor(orangeView.topAnchor).active = true
        leftConstraint = greenView.leftAnchor.constraintEqualToAnchor(orangeView.rightAnchor, constant: 80)
        leftConstraint?.active = true
        greenView.heightAnchor.constraintEqualToAnchor(orangeView.heightAnchor).active = true
        greenView.widthAnchor.constraintEqualToAnchor(orangeView.widthAnchor).active = true

动画的执行

    override func viewDidLoad() {
        super.viewDidLoad()
        snpLayout()
        anchorLayout()
        
        let kissButton = UIButton(type: .System)
        kissButton.setTitle("Kiss", forState: .Normal)
        kissButton.addTarget(self, action: #selector(ViewController.kissButtonClick(_:)), forControlEvents: .TouchUpInside)
        view.addSubview(kissButton)
        kissButton.snp_makeConstraints { (make) in
            make.bottom.equalTo(view).offset(-20)
            make.centerX.equalTo(view)
            make.width.equalTo(view).multipliedBy(0.8)
            make.height.equalTo(60)
        }
    }
    
    func kissButtonClick(sender: UIButton) {
        UIView.animateWithDuration(1.5, delay: 0, options: [.Repeat, .CurveEaseInOut], animations: {
            self.redView.snp_updateConstraints(closure: { (make) in
                make.left.equalTo(self.yellowView.snp_right).offset(0)
            })
            
            self.leftConstraint?.constant = 0
            self.view.layoutIfNeeded()
            }, completion: nil)
    }

效果图

kissView.gif