如何在Swift中为UIImages创建一个闪烁的指针效果

时间:2018-03-03 21:06:23

标签: ios arrays swift uiimageview uiimage

我正在尝试在Swift中创建指针效果。我有六个UIImageView,每个都有一个以循环方式排序的UIImage。我想创建一个动画,让每个图像闪烁一段时间(就好像它是一个指针指示)。

我想过创建一个带有透明版图像的数组,然后从中创建一个动画序列,但持续时间会混淆。

这是我想要实现的想法。我希望这些图像能够逐一产生这种闪烁效果。

idea description

1 个答案:

答案 0 :(得分:1)

enter image description here

这就是我将视图放在圆圈中并使它们“闪现”的方法。

  • 首先我创建了常规视图(我不想使用ImageView,但您可以根据需要更改代码)..

  • 我计算了需要围绕具有一定半径的中心点放置视图的角度,以使它们放置在一个圆圈中。

  • 接下来我创建一个动画功能,它既有正向动画又有反向动画(我无法使autoreverses标志起作用)..

  • 要让一个人在另一个之后显示,我只需添加一个延迟(x2因为正向+反向)..

  • 为了弄清楚所有动画何时完成,我将整个功能包裹在CATransaction中。

注意:如果您不需要圆形展示位置代码,只需将其删除即可。 AFAIK,你只需要动画代码。

//
//  ViewController.swift
//  TestSO
//
//  Created by Brandon on 2018-03-03.
//  Copyright © 2018 XIO. All rights reserved.
//

import UIKit

extension UIColor {
    class func random() -> UIColor {
        let rand = { (max: CGFloat) -> CGFloat in
            let rnd = CGFloat(arc4random()) / CGFloat(UInt32.max)
            return rnd * max
        }

        return UIColor(red: rand(1.0), green: rand(1.0), blue: rand(1.0), alpha: 1.0)
    }
}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let makeView = { () -> UIView in
            let view = UIView()
            view.backgroundColor = UIColor.random()
            view.frame = CGRect(x: 0.0, y: 0.0, width: 50.0, height: 50.0)
            self.view.addSubview(view)
            return view
        }

        let imageViews = [
            makeView(),
            makeView(),
            makeView(),
            makeView(),
            makeView(),
            makeView()
        ]

        let locationForView = { (angle: CGFloat, center: CGPoint, radius: CGFloat) -> CGPoint in
            let angle = angle * CGFloat.pi / 180.0
            return CGPoint(x: center.x - radius * cos(angle), y: center.y + radius * sin(angle))
        }

        for i in 0..<imageViews.count {
            let center = self.view.center
            let radius = ((150.0 + imageViews[i].bounds.size.width) / 2.0)
            let count = imageViews.count
            imageViews[i].center = locationForView(((360.0 / CGFloat(count)) * CGFloat(i)) + 90.0, center, radius)
        }

        self.animate(views: imageViews.reversed(), duration: 3.0, intervalDelay: 0.5)
    }

    private func animate(views: [UIView], duration: TimeInterval, intervalDelay: TimeInterval) {

        CATransaction.begin()
        CATransaction.setCompletionBlock {
            print("COMPLETED ALL ANIMATIONS")
        }

        var delay: TimeInterval = 0.0
        let interval = duration / TimeInterval(views.count)

        for view in views {
            let colour = view.backgroundColor
            let transform = view.transform

            UIView.animate(withDuration: interval, delay: delay, options: [.curveEaseIn], animations: {

                view.backgroundColor = UIColor.red
                view.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)

            }, completion: { (finished) in

                UIView.animate(withDuration: interval, delay: 0.0, options: [.curveEaseIn], animations: {

                    view.backgroundColor = colour
                    view.transform = transform

                }, completion: { (finished) in


                })
            })

            delay += (interval * 2.0) + intervalDelay
        }
        CATransaction.commit()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}