ios - 向 UIDynamicAnimator 添加超过 32 个 UIFieldBehaviors 会导致 SIGABRT

Question

我有以下代码。当我迭代 25 次 (5 * 5) 时，它工作正常。当我迭代 36 次时(for 循环中为 6 * 6)，它因 SIGABRT 而崩溃。我已经粘贴了错误的图像(Xcode 中的 Playgrounds 不允许我复制粘贴它)。这是一个内部错误，某处定义了 32 个行为的限制，还是我的代码中的错误？谢谢!

//: A UIKit based Playground for presenting user interface

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    var animator : UIDynamicAnimator!

    var springfields : [UIFieldBehavior] = []

    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white
        animator = UIDynamicAnimator(referenceView: view)

        for i in 1...6 {
            for j in 1...6 {
                let newView = UIView()
                let dotwidth = 12
                newView.layer.cornerRadius = CGFloat(dotwidth/2);
                newView.frame = CGRect(x:20+i*25, y:20+j*25, width:dotwidth, height:dotwidth)
                newView.clipsToBounds = true
                newView.backgroundColor = .black

                let newSpringField = UIFieldBehavior.springField()
                springfields.append(newSpringField)
                newSpringField.addItem(newView)
                newSpringField.position = newView.center

                view.addSubview(newView)

                animator.addBehavior(newSpringField)
            }
        }

        self.view = view
    }
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
PlaygroundPage.current.needsIndefiniteExecution = true

Answer 1

在应用程序中运行您的代码，调试控制台输出为:

*** Terminating app due to uncaught exception 'Invalid Association', reason: 'UIDynamicAnimator supports a maximum of 32 distinct fields'