这是我的第一个 iOS 开发,所以我正在使用这个小项目来了解系统的工作原理以及语言 (swift) 的工作原理。
我正在尝试制作一个类似于android应用和一定数量的iOS应用的抽屉菜单。
我发现这个教程很好地解释了如何做以及它是如何工作的:here
现在,因为我正在使用带有显示的 NavigationController,所以我必须修改它的完成方式。
我将 UIViewControllerTransitioningDelegate 换成了 UINavigationControllerDelegate,这样我就可以覆盖 navigationController 函数。
这意味着我可以取出抽屉并关闭它。它适用于按钮或手势。 我的问题如下:如果我没有完成将抽屉拖动到足够远以使其达到阈值并完成动画,它将被取消并隐藏。这一切都很好,但是当发生这种情况时,不会调用关闭函数,这意味着我在 PresentMenuAnimator 中放置的快照仍然在所有层的前面,我什至被困在那里尽管我可以与它背后的东西互动。
如何使用 NavigationController 捕获解雇或取消?这可能吗?
交互者:
import UIKit
class Interactor:UIPercentDrivenInteractiveTransition {
var hasStarted: Bool = false;
var shouldFinish: Bool = false;
}
菜单助手:
import Foundation
import UIKit
enum Direction {
case Up
case Down
case Left
case Right
}
struct MenuHelper {
static let menuWith:CGFloat = 0.8;
static let percentThreshold:CGFloat = 0.6;
static let snapshotNumber = 12345;
static func calculateProgress(translationInView:CGPoint, viewBounds:CGRect, direction: Direction) -> CGFloat {
let pointOnAxis:CGFloat;
let axisLength:CGFloat;
switch direction {
case .Up, .Down :
pointOnAxis = translationInView.y;
axisLength = viewBounds.height;
case .Left, .Right :
pointOnAxis = translationInView.x;
axisLength = viewBounds.width;
}
let movementOnAxis = pointOnAxis/axisLength;
let positiveMovementOnAxis:Float;
let positiveMovementOnAxisPercent:Float;
switch direction {
case .Right, .Down:
positiveMovementOnAxis = fmaxf(Float(movementOnAxis), 0.0);
positiveMovementOnAxisPercent = fminf(positiveMovementOnAxis, 1.0);
return CGFloat(positiveMovementOnAxisPercent);
case .Left, .Up :
positiveMovementOnAxis = fminf(Float(movementOnAxis), 0.0);
positiveMovementOnAxisPercent = fmaxf(positiveMovementOnAxis, -1.0);
return CGFloat(-positiveMovementOnAxisPercent);
}
}
static func mapGestureStateToInteractor(gestureState:UIGestureRecognizerState, progress:CGFloat, interactor: Interactor?, triggerSegue: () -> Void ) {
guard let interactor = interactor else {return };
switch gestureState {
case .began :
interactor.hasStarted = true;
interactor.shouldFinish = false;
triggerSegue();
case .changed :
interactor.shouldFinish = progress > percentThreshold;
interactor.update(progress);
case .cancelled :
interactor.hasStarted = false;
interactor.shouldFinish = false;
interactor.cancel();
case .ended :
interactor.hasStarted = false;
interactor.shouldFinish
? interactor.finish()
: interactor.cancel();
interactor.shouldFinish = false;
default :
break;
}
}
}
菜单导航 Controller :
import Foundation
import UIKit
class MenuNavigationController: UINavigationController, UINavigationControllerDelegate {
let interactor = Interactor()
override func viewDidLoad() {
super.viewDidLoad();
self.delegate = self;
}
func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
if((toVC as? MenuViewController) != nil) {
return PresentMenuAnimator();
}
else {
return DismissMenuAnimator();
}
}
func navigationController(_ navigationController: UINavigationController, interactionControllerFor animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
return interactor.hasStarted ? interactor : nil;
}
}
PresentMenuAnimator :
import UIKit
class PresentMenuAnimator: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.6;
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard
let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from),
let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)
else {return};
let containerView = transitionContext.containerView;
containerView.insertSubview(toVC.view, aboveSubview: fromVC.view);
let snapshot = fromVC.view.snapshotView(afterScreenUpdates: false);
snapshot?.tag = MenuHelper.snapshotNumber;
snapshot?.isUserInteractionEnabled = false;
snapshot?.layer.shadowOpacity = 0.7;
containerView.insertSubview(snapshot!, aboveSubview: toVC.view);
fromVC.view.isHidden = true;
UIView.animate(withDuration: transitionDuration(using: transitionContext),
animations: {snapshot?.center.x+=UIScreen.main.bounds.width*MenuHelper.menuWith;},
completion: {_ in
fromVC.view.isHidden = false;
transitionContext.completeTransition(!transitionContext.transitionWasCancelled);}
);
}
}
关闭菜单动画器:
import UIKit
class DismissMenuAnimator : NSObject {
}
extension DismissMenuAnimator : UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.6;
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard
let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from),
let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)
else {
return
}
let containerView = transitionContext.containerView;
let snapshot = containerView.viewWithTag(MenuHelper.snapshotNumber)
UIView.animate(withDuration: transitionDuration(using: transitionContext),
animations: {
snapshot?.frame = CGRect(origin: CGPoint.zero, size: UIScreen.main.bounds.size)
},
completion: { _ in
let didTransitionComplete = !transitionContext.transitionWasCancelled
if didTransitionComplete {
containerView.insertSubview(toVC.view, aboveSubview: fromVC.view)
snapshot?.removeFromSuperview()
}
transitionContext.completeTransition(didTransitionComplete)
}
)
}
}
最佳答案
可以知道动画是否被取消,可以在的
。 func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool)
方法中捕获UINavigationControllerDelegate
以下是有关如何执行此操作的代码片段:
func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
navigationController.transitionCoordinator?.notifyWhenInteractionEnds { context in
if context.isCancelled {
// The interactive back transition was cancelled
}
}
}
此方法可以放在您的 MenuNavigationController
中,您可以在其中保留您的 PresentMenuAnimator
并告诉它转换已取消,并在其中删除挂起的快照周围。
关于ios - swift : UIPercentDrivenInteractiveTransition on cancel?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45076085/