旋转的菊花

Created by 大刘 liuxing8807@126.com

一次小记录: UI同学设计了一个旋转的菊花，不使用 UIActivityIndicatorView，于是我们用代码实现，这是一个非常小的功能，不过，直接让view本身旋转并不太合适，旋转本身和视图可以分离

import Foundation
import UIKit

class ZZRotation: NSObject {
    var isAnimating: Bool = false
    weak var attachView: UIView? = nil
    
    /// Start attachView rotation
    func start() {
        guard let _ = self.attachView else {
            return
        }
        if !self.isAnimating {
            self.isAnimating = true
            start(option: UIView.AnimationOptions.curveEaseIn)
        }
    }
    
    func start(option: UIView.AnimationOptions) {
        // this spin completes 360 degrees every 2 seconds
        UIView.animate(withDuration: 0.3, delay: 0.0, options: option) {
            print("en")
            guard let attachView = self.attachView else {
                return
            }
            attachView.transform = attachView.transform.rotated(by: CGFloat.pi/2)
        } completion: { (isFinish) in
            if isFinish {
                if self.isAnimating {
                    // if flag still set, keep spinning with constant speed
                    self.start(option: UIView.AnimationOptions.curveLinear)
                } else {
                    // one last spin, with deceleration
                    self.start(option: UIView.AnimationOptions.curveEaseOut)
                }
            }
        }
    }
    
    /// Stop attachView rotation
    func stop() {
        guard let _ = self.attachView else {
            return
        }
    }
}

测试

import UIKit

class ViewController: UIViewController {
    let imageView: UIImageView = UIImageView()
    let rotation: ZZRotation = ZZRotation()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.black
        
        let image: UIImage = UIImage(named: "spin")!
        imageView.frame = CGRect.init(x: 0, y: 0, width: image.size.width+10, height: image.size.height+10)
        imageView.center = self.view.center
        imageView.image = image
        self.view.addSubview(imageView)
        self.rotation.attachView = imageView
        self.rotation.start()
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.rotation.stop()
    }
}