UINavigationController的完成处理程序" pushViewController：animated"？ [英] Completion handler for UINavigationController "pushViewController:animated"?

问题描述

我是关于使用 UINavigationController 创建应用程序来呈现下一个视图控制器。
iOS5有一种新方法来呈现 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完成处理程序的UINavigationController ？
只有

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

pushViewController:animated:

是否可以创建我自己的完成处理程序，如新的 presentViewController：animated：completion：？

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

推荐答案

请参阅 par的回答另一个和更新的解决方案

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

UINavigationController 动画以<$ c $运行c> CoreAnimation ，因此将代码封装在 CATransaction 中是有意义的，从而设置完成块。

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

Swift ：

对于swift，我建议创建一个扩展名

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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