UIStackView

import UIKit

class ViewController: UIViewController
{
    
    @IBOutlet weak var verticalStackView: UIStackView!  // 垂直StackView
    @IBOutlet weak var horizontalStackView: UIStackView!    // 水平StackView
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning()
    {
        super.didReceiveMemoryWarning()
                // Dispose of any resources that can be recreated.
    }
    
    /**
     添加星星
     
     - parameter sender: Btn
     */
    @IBAction func addStarOnClick(sender: UIButton) {
        
        // 创建ImageView
        let starImgVw:UIImageView = UIImageView(image: UIImage(named: "star"))
        // 设置内容自动适配
        starImgVw.contentMode = .ScaleAspectFit
        // 加入StackView的子View
        self.horizontalStackView.addArrangedSubview(starImgVw)
        // 更新界面放入UIVew动画中
        UIView.animateWithDuration(0.25, animations: {
            self.horizontalStackView.layoutIfNeeded()
        })
    }
    
    /**
     移除星星
     
     - parameter sender: Btn
     */
    @IBAction func removeStar(sender: AnyObject) {
        let star:UIView? = self.horizontalStackView.arrangedSubviews.last
        if let aStar = star
        {
            self.horizontalStackView.removeArrangedSubview(aStar)
            aStar.removeFromSuperview()
            UIView.animateWithDuration(0.25, animations: {
                self.horizontalStackView.layoutIfNeeded()
            })
        }
    }

}```

![stackView.gif](https://img.haomeiwen.com/i189984/cf5c95e47ffdabb4.gif?imageMogr2/auto-orient/strip)

- xib上对已经存在的View嵌套UIStackView