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

我正在使用创建一个应用程序UINavigationController呈现下一个视图控制器。 iOS5 提供了一种新的呈现方法UIViewControllers:

presentViewController:animated:completion:

现在我问我为什么没有一个完成处理程序UINavigationController？ 仅有

pushViewController:animated:

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

See 帕的回答 https://stackoverflow.com/a/33767837/246776另一个更新的解决方案

UINavigationController动画运行于CoreAnimation，因此将代码封装在其中是有意义的CATransaction从而设置一个完成块。

Swift:

为了快速，我建议创建一个这样的扩展

extension UINavigationController {

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

}

Usage:

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

Objective-C

Header:

#import <UIKit/UIKit.h>

@interface UINavigationController (CompletionHandler)

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

@end

执行：

#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