Question

我正在尝试设置CAEmitter。所有这些都有效，但我希望在一秒钟后将birthRate更改为零，以便动画停止并且不会产生新的粒子。这是我目前的代码：

import PlaygroundSupport
import UIKit

let view = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))

let emitterLayer = CAEmitterLayer()

func degreesToRadians(degrees: Double) -> CGFloat {
    return CGFloat(degrees * M_PI / 180.0)
}

emitterLayer.emitterPosition = CGPoint(x: 320, y: 150)

let cell = CAEmitterCell()
cell.birthRate = 100
cell.lifetime = 1
cell.velocity = 300
cell.scale = 0.1

cell.contents = #imageLiteral(resourceName: "Lock copy.png").cgImage

let zeroDegreesInRadians = degreesToRadians(degrees: 0.0)
cell.spin = degreesToRadians(degrees: 130.0)
cell.spinRange = zeroDegreesInRadians
cell.emissionRange = degreesToRadians(degrees: 100)

cell.xAcceleration = -800.0
cell.yAcceleration = 1000.0

emitterLayer.emitterCells = [cell]

let delayTime = DispatchTime.now() + Double(Int64(1.0 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)
DispatchQueue.main.asyncAfter(deadline: delayTime, execute:{
    cell.birthRate = 0
})

view.layer.addSublayer(emitterLayer)

let page = PlaygroundPage.current
page.needsIndefiniteExecution = true
page.liveView = view

我看不到任何影响，为什么我的代码不起作用？另外，我如何添加CABasicAnimation来更改属性。 CAEmitterCell没有类似.add(anim: CAAnimation, forKey: String)的方法。它会被添加到图层中吗？谢谢你的帮助。

Answer 1

您应该将emitterLayer的birthRate设置为零。

或者，您也可以使用emitterLayer的生命周期为零。

无法更改CAEmitter SWIFT的属性

1 个答案: