点击按钮开始动画
@IBAction func rightHeartButtonClicked(_ sender: UIButton) {
sender.isUserInteractionEnabled = false
// 1秒发射5个粒子，0.2秒发射1个粒子，从上0.2秒开始动画，使按钮点击后立即发射粒子
rightHeartLayer.beginTime = CACurrentMediaTime() - 0.2
rightHeartLayer.birthRate = 1
DispatchQueue.main.asyncAfter(deadline: .now() + 0.8) { [weak self] in
guard let strongSelf = self else { return }
strongSelf.rightHeartLayer.birthRate = 0
}
DispatchQueue.main.asyncAfter(deadline: .now() + 1.6) { [weak self] in
guard self != nil else { return }
sender.isUserInteractionEnabled = true
}
}
抛物线粒子动画效果
实现抛物线动画需要给粒子加上重力加速度。此外，这里还加入粒子旋转效果，同时发射两种粒子。
给控制器添加类型为 CAEmitterLayer 的属性 gravityLayer，在 viewDidLoad 方法中对此属性进行初始化
private var gravityLayer: CAEmitterLayer!
private func setupGravityLayer() {
gravityLayer = CAEmitterLayer()
gravityLayer.renderMode = kCAEmitterLayerOldestFirst
gravityLayer.emitterPosition = CGPoint(x: 0, y: view.bounds.maxY)
gravityLayer.birthRate = 0
let cell = CAEmitterCell()
cell.contents = #imageLiteral(resourceName: "Heart_red").cgImage
cell.scale = 0.5
cell.lifetime = 10
cell.alphaSpeed = -0.1
cell.birthRate = 10
cell.velocity = 100
// y轴方法的加速度，模拟重力加速度
cell.yAcceleration = 20
cell.emissionLongitude = -CGFloat.pi / 4
cell.emissionRange = CGFloat.pi / 4
// 粒子旋转角速度，单位是弧度/秒，正值表示顺时针旋转
// 这句可以省略，默认值是零
cell.spin = 0
// 粒子旋转角速度变化范围
cell.spinRange = CGFloat.pi * 2
let cell2 = CAEmitterCell()
cell2.contents = #imageLiteral(resourceName: "Heart_blue").cgImage
cell2.scale = 0.3
cell2.lifetime = 20
cell2.alphaSpeed = -0.05
cell2.birthRate = 5
cell2.velocity = 135
cell2.yAcceleration = 20
cell2.emissionLongitude = -CGFloat.pi / 4
cell2.emissionRange = CGFloat.pi / 4
cell2.spin = 0
cell2.spinRange = CGFloat.pi * 2
// 图层要发射2种粒子
gravityLayer.emitterCells = [cell, cell2]
view.layer.addSublayer(gravityLayer)
}
点击开始或停止动画
@IBAction func gravityButtonClicked(_ sender: UIButton) {
if gravityLayer.birthRate == 0 {
gravityLayer.beginTime = CACurrentMediaTime()
gravityLayer.birthRate = 1
} else {
gravityLayer.birthRate = 0
}
}
以上是动画的实现方法，代码已上传 GitHub：https://github.com/Silence-GitHub/CoreAnimationDemo
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持ASPKU。
注：相关教程知识阅读请移步到IOS开发频道。
