UINavigationController“pushViewController:animated"的完成处理程序?

Completion handler for UINavigationController quot;pushViewController:animatedquot;?(UINavigationController“pushViewController:animated的完成处理程序?)

问题描述

我打算使用 UINavigationController 创建一个应用程序来展示下一个视图控制器.在 iOS5 中，有一种新的方法来呈现 UIViewControllers:

I'm about creating an app using a UINavigationController to present the next view controllers. With iOS5 there´s a new method to presenting UIViewControllers:

presentViewController:animated:completion:

现在我问我为什么没有 UINavigationController 的完成处理程序?只有

Now I ask me why isn´t there a completion handler for UINavigationController? There are just

pushViewController:animated:

是否可以像新的 presentViewController:animated:completion: 那样创建我自己的完成处理程序?

Is it possible to create my own completion handler like the new presentViewController:animated:completion: ?

推荐答案

请参阅 par's answer 了解另一个和更多最新解决方案

See par's answer for another and more up to date solution

UINavigationController 动画使用 CoreAnimation 运行，因此将代码封装在 CATransaction 中并设置完成块是有意义的.

UINavigationController animations are run with CoreAnimation, so it would make sense to encapsulate the code within CATransaction and thus set a completion block.

斯威夫特:

为了快速，我建议创建一个这样的扩展

For swift I suggest creating an extension as such

extension UINavigationController {

  public func pushViewController(viewController: UIViewController,
                                 animated: Bool,
                                 completion: @escaping (() -> Void)?) {
    CATransaction.begin()
    CATransaction.setCompletionBlock(completion)
    pushViewController(viewController, animated: animated)
    CATransaction.commit()
  }

}

用法:

navigationController?.pushViewController(vc, animated: true) {
  // Animation done
}

Objective-C

标题:

#import <UIKit/UIKit.h>

@interface UINavigationController (CompletionHandler)

- (void)completionhandler_pushViewController:(UIViewController *)viewController
                                    animated:(BOOL)animated
                                  completion:(void (^)(void))completion;

@end

实施:

#import "UINavigationController+CompletionHandler.h"
#import <QuartzCore/QuartzCore.h>

@implementation UINavigationController (CompletionHandler)

- (void)completionhandler_pushViewController:(UIViewController *)viewController 
                                    animated:(BOOL)animated 
                                  completion:(void (^)(void))completion 
{
    [CATransaction begin];
    [CATransaction setCompletionBlock:completion];
    [self pushViewController:viewController animated:animated];
    [CATransaction commit];
}

@end

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