Swift粒子动画

import UIKit

protocol Emitterable {
    
}
//这里的 where Self : UIViewController 意思是对使用该效果必须继承自UIViewController
extension Emitterable where Self : UIViewController {
    func start() {
        
        // 1.创建发射器
        let emitter = CAEmitterLayer()
        
        // 2.设置发射器的位置
        emitter.emitterPosition = CGPoint(x: view.bounds.width * 0.5, y: -60)
        
        // 3.开启三维效果
        emitter.preservesDepth = true
        
        // 4.创建例子, 并且设置例子相关的属性
        // 4.1.创建例子Cell
        let cell = CAEmitterCell()
        
        // 4.2.设置粒子速度
        cell.velocity = 150
        cell.velocityRange = 100
        
        // 4.3.设置例子的大小
        cell.scale = 0.7
        cell.scaleRange = 0.3
        
        // 4.4.设置粒子方向
        cell.emissionLongitude = CGFloat(M_PI_2)
        cell.emissionRange = CGFloat(M_PI_2 / 2)
        
        // 4.5.设置例子的存活时间
        cell.lifetime = 6
        cell.lifetimeRange = 1.5
        
        // 4.6.设置粒子旋转
        cell.spin = CGFloat(M_PI_2)
        cell.spinRange = CGFloat(M_PI_2 / 2)
        
        // 4.6.设置例子每秒弹出的个数
        cell.birthRate = 20
        
        // 4.7.设置粒子展示的图片
        cell.contents = UIImage(named: "good6_30x30")?.cgImage
        
        // 5.将粒子设置到发射器中
        emitter.emitterCells = [cell]
        
        // 6.将发射器的layer添加到父layer中
        view.layer.addSublayer(emitter)
    }
    
    func stop() {
        /*
        for layer in view.layer.sublayers! {
            if layer.isKind(of: CAEmitterLayer.self) {
                layer.removeFromSuperlayer()
            }
        }
        */
        view.layer.sublayers?.filter({ $0.isKind(of: CAEmitterLayer.self)}).first?.removeFromSuperlayer()
    }
}

调用很简单:

class ViewController: UIViewController , Emitterable {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func touchesBegan(_ touches: Set, with event: UIEvent?) {
        
        self.start()
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 5) {

            self.stop()
        }
    }
}

效果:

Snip20161212_5.png