我正在尝试自定义过渡动画.我创建了一个符合UIViewControllerAnimatedTransitioning的动画对象：
import UIKit
class ViewControllerAnimator: NSObject,UIViewControllerAnimatedTransitioning {
let duration = 1.0
func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
return duration
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
let fromView = transitionContext.viewForKey(UITransitionContextFromViewKey)!
//Animate out
UIView.animateWithDuration(duration,animations: { () -> Void in
fromView.frame.origin.x -= 200
}) { (Bool) -> Void in
transitionContext.completeTransition(true)
}
}
}
我在尝试设置fromView的框架时遇到错误.它试图强行解开零时崩溃.我在这做错了什么？为什么我的fromView没有？
