如何从屏幕顶部而不是底部呈现 UIViewController？

Question

我正在使用 UIViewController 并使用 PresentModalViewController:controllerr 动画:YES 来呈现它，但我想如果它从屏幕顶部向下滑动而不是从底部向上滑动，有什么方法可以做到这一点？

Answer 1

我创建了一个用于从所有 4 个方向推送 ViewControllers 的函数：

- (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)
                               }
                           })
        }
    }
}

Answer 3

我使用以下代码从顶部对视图控制器进行动画处理。

[self.mainViewController.view addSubview:modalViewController.view];
modalViewController.view.frame = CGRectMake(modalViewController.view.frame.origin.x,
                                            -modalViewController.view.frame.size.height,
                                            modalViewController.view.frame.size.width,
                                            modalViewController.view.frame.size.height);

[UIView animateWithDuration:0.4 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^(void){

    modalViewController.view.frame = CGRectMake(modalViewController.view.frame.origin.x,
                                                0,
                                                modalViewController.view.frame.size.width,
                                                modalViewController.view.frame.size.height);

} completion:^(BOOL finished){

    [modalViewController.view removeFromSuperview];
    [self.mainViewController presentViewController:modalViewController animated:NO completion:nil];

}];

它将 modalViewController 的 UIView 添加到 mainViewController，为其添加动画，然后从 mainViewController 中删除 UIView。 code>mainViewController 和 presentsViewController: 没有动画。

Answer 4

您所描述的不是内置的过渡样式；而是内置的过渡样式。请参阅此处查看 Apple 提供的列表。如果您绝对需要视图控制器以这种方式显示，则必须自己为其设置动画。

Answer 5

您必须#importQuartzCore框架并添加过渡动画，然后更改：

animated:YES
到：
动画：否。