你如何从屏幕顶部而不是底部呈现UIViewController？

Question

我正在使用UIViewController,我使用presentModalViewController:controllerr animated:YES来呈现它,但我想它是否会从屏幕顶部向下滑动而不是从底部向下滑动,任何方式都可以这样做？

Answer 1

我创建了一个用于推动ViewControllers所有4个方向的功能:

- (void) slideLayerInDirection:(NSString *)direction andPush:(UIViewController *)dstVC {
  CATransition* transition = [CATransition animation];
  transition.duration = 0.5;
  transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
  transition.type = kCATransitionPush;
  transition.subtype = direction;
  [self.view.layer addAnimation:transition forKey:kCATransition];
  [self pushViewController:dstVC animated:NO];
}

头文件包含以下内容:

#import <QuartzCore/QuartzCore.h>

#define direction_left kCATransitionFromLeft
#define direction_top kCATransitionFromBottom
#define direction_right kCATransitionFromRight
#define direction_bottom kCATransitionFromTop

Answer 2

public extension UINavigationController {

    func pushViewControllerFromTop(viewController vc: UIViewController) {
        vc.view.alpha = 0
        self.present(vc, animated: false) { () -> Void in
            vc.view.frame = CGRect(x: 0, y: -vc.view.frame.height, width: vc.view.frame.width, height: vc.view.frame.height)
            vc.view.alpha = 1
            UIView.animate(withDuration: 1, 
                           animations: { () -> Void in
                               vc.view.frame = CGRect(x: 0, y: 0, width: vc.view.frame.width, height: vc.view.frame.height)
                           }, 
                           completion: nil)
        }
    }

    func dismissViewControllerToTop() {
        if let vc = self.presentedViewController {
            UIView.animate(withDuration: 1, 
                           animations: { () -> Void in
                               vc.view.frame = CGRect(x: 0, y: -vc.view.frame.height, width: vc.view.frame.width, height: vc.view.frame.height)
                           }, 
                           completion: { complete -> Void in
                               if complete {
                                   self.dismiss(animated: false, completion: nil)
                               }
                           })
        }
    }
}