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

Completion handler for UINavigationController "pushViewController:animated"?

提问by geforce

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

我将使用 a 创建一个应用程序UINavigationController来呈现下一个视图控制器。在 iOS5 中有一种新的呈现方法UIViewControllers：

presentViewController:animated:completion:

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

现在我问我为什么没有完成处理程序UINavigationController？有只是

pushViewController:animated:

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

是否可以像 new 一样创建我自己的完成处理程序presentViewController:animated:completion:？

回答by chrs

See par's answerfor another and more up to date solution

请参阅par 的答案以获取另一个更新的解决方案

UINavigationControlleranimations are run with CoreAnimation, so it would make sense to encapsulate the code within CATransactionand thus set a completion block.

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

Swift:

斯威夫特：

For swift I suggest creating an extension as such

对于 swift 我建议创建一个扩展

extension UINavigationController {

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

}

Usage:

用法：

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

Objective-C

目标-C

Header:

标题：

#import <UIKit/UIKit.h>

@interface UINavigationController (CompletionHandler)

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

@end

Implementation:

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

回答by par

iOS 7+ Swift

iOS 7+ 斯威夫特

Swift 4:

斯威夫特 4：

// 2018.10.30 par:
//   I've updated this answer with an asynchronous dispatch to the main queue
//   when we're called without animation. This really should have been in the
//   previous solutions I gave but I forgot to add it.
extension UINavigationController {
    public func pushViewController(
        _ viewController: UIViewController,
        animated: Bool,
        completion: @escaping () -> Void)
    {
        pushViewController(viewController, animated: animated)

        guard animated, let coordinator = transitionCoordinator else {
            DispatchQueue.main.async { completion() }
            return
        }

        coordinator.animate(alongsideTransition: nil) { _ in completion() }
    }

    func popViewController(
        animated: Bool,
        completion: @escaping () -> Void)
    {
        popViewController(animated: animated)

        guard animated, let coordinator = transitionCoordinator else {
            DispatchQueue.main.async { completion() }
            return
        }

        coordinator.animate(alongsideTransition: nil) { _ in completion() }
    }
}

---

---

EDIT: I've added a Swift 3 version of my original answer. In this version I've removed the example co-animation shown in the Swift 2 version as it seems to have confused a lot of people.

编辑：我添加了我的原始答案的 Swift 3 版本。在这个版本中，我删除了 Swift 2 版本中显示的示例协同动画，因为它似乎让很多人感到困惑。

Swift 3:

斯威夫特 3：

import UIKit

// Swift 3 version, no co-animation (alongsideTransition parameter is nil)
extension UINavigationController {
    public func pushViewController(
        _ viewController: UIViewController,
        animated: Bool,
        completion: @escaping (Void) -> Void)
    {
        pushViewController(viewController, animated: animated)

        guard animated, let coordinator = transitionCoordinator else {
            completion()
            return
        }

        coordinator.animate(alongsideTransition: nil) { _ in completion() }
    }
}

Swift 2:

斯威夫特 2：

import UIKit

// Swift 2 Version, shows example co-animation (status bar update)
extension UINavigationController {
    public func pushViewController(
        viewController: UIViewController,
        animated: Bool,
        completion: Void -> Void)
    {
        pushViewController(viewController, animated: animated)

        guard animated, let coordinator = transitionCoordinator() else {
            completion()
            return
        }

        coordinator.animateAlongsideTransition(
            // pass nil here or do something animated if you'd like, e.g.:
            { context in
                viewController.setNeedsStatusBarAppearanceUpdate()
            },
            completion: { context in
                completion()
            }
        )
    }
}

回答by Daniel

Based on par's answer(which was the only one that worked with iOS9), but simpler and with a missing else (which could have led to the completion never being called):

基于par 的答案（这是唯一一个适用于 iOS9 的答案），但更简单并且缺少 else（这可能导致从未调用完成）：

extension UINavigationController {
    func pushViewController(_ viewController: UIViewController, animated: Bool, completion: @escaping () -> Void) {
        pushViewController(viewController, animated: animated)

        if animated, let coordinator = transitionCoordinator {
            coordinator.animate(alongsideTransition: nil) { _ in
                completion()
            }
        } else {
            completion()
        }
    }

    func popViewController(animated: Bool, completion: @escaping () -> Void) {
        popViewController(animated: animated)

        if animated, let coordinator = transitionCoordinator {
            coordinator.animate(alongsideTransition: nil) { _ in
                completion()
            }
        } else {
            completion()
        }
    }
}

回答by Klaas

Currently the UINavigationControllerdoes not support this. But there's the UINavigationControllerDelegatethat you can use.

目前UINavigationController不支持这个。但是有UINavigationControllerDelegate你可以使用的。

An easy way to accomplish this is by subclassing UINavigationControllerand adding a completion block property:

实现此目的的一种简单方法是通过子类化UINavigationController并添加完成块属性：

@interface PbNavigationController : UINavigationController <UINavigationControllerDelegate>

@property (nonatomic,copy) dispatch_block_t completionBlock;

@end


@implementation PbNavigationController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.delegate = self;
    }
    return self;
}

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    NSLog(@"didShowViewController:%@", viewController);

    if (self.completionBlock) {
        self.completionBlock();
        self.completionBlock = nil;
    }
}

@end

Before pushing the new view controller you would have to set the completion block:

在推送新的视图控制器之前，您必须设置完成块：

UIViewController *vc = ...;
((PbNavigationController *)self.navigationController).completionBlock = ^ {
    NSLog(@"COMPLETED");
};
[self.navigationController pushViewController:vc animated:YES];

This new subclass can either be assigned in Interface Builder or be used programmatically like this:

这个新的子类可以在 Interface Builder 中分配，也可以像这样以编程方式使用：

PbNavigationController *nc = [[PbNavigationController alloc]initWithRootViewController:yourRootViewController];

回答by Francois Nadeau

Here is the Swift 4 version with the Pop.

这是带有 Pop 的 Swift 4 版本。

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

    public func popViewController(animated: Bool,
                                  completion: (() -> Void)?) {
        CATransaction.begin()
        CATransaction.setCompletionBlock(completion)
        popViewController(animated: animated)
        CATransaction.commit()
    }
}

Just in case someone else needs this.

以防万一其他人需要这个。

回答by Sam

To expand on @Klaas' answer (and as a result of thisquestion) I've added completion blocks directly to the push method:

为了扩展@Klaas 的回答（以及作为这个问题的结果），我已将完成块直接添加到 push 方法中：

@interface PbNavigationController : UINavigationController <UINavigationControllerDelegate>

@property (nonatomic,copy) dispatch_block_t completionBlock;
@property (nonatomic,strong) UIViewController * pushedVC;

@end


@implementation PbNavigationController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.delegate = self;
    }
    return self;
}

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    NSLog(@"didShowViewController:%@", viewController);

    if (self.completionBlock && self.pushedVC == viewController) {
        self.completionBlock();
    }
    self.completionBlock = nil;
    self.pushedVC = nil;
}

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    if (self.pushedVC != viewController) {
        self.pushedVC = nil;
        self.completionBlock = nil;
    }
}

-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated completion:(dispatch_block_t)completion {
    self.pushedVC = viewController;
    self.completionBlock = completion;
    [self pushViewController:viewController animated:animated];
}

@end

To be used as follows:

使用方法如下：

UIViewController *vc = ...;
[(PbNavigationController *)self.navigationController pushViewController:vc animated:YES completion:^ {
    NSLog(@"COMPLETED");
}];

回答by wj2061

Since iOS 7.0,you can use UIViewControllerTransitionCoordinatorto add a push completion block:

从 iOS 7.0 开始，您可以使用UIViewControllerTransitionCoordinator添加推送完成块：

UINavigationController *nav = self.navigationController;
[nav pushViewController:vc animated:YES];

id<UIViewControllerTransitionCoordinator> coordinator = vc.transitionCoordinator;
[coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext>  _Nonnull context) {

} completion:^(id<UIViewControllerTransitionCoordinatorContext>  _Nonnull context) {
    NSLog(@"push completed");
}];

回答by rahul_send89

Swift 2.0

斯威夫特 2.0

extension UINavigationController : UINavigationControllerDelegate {
    private struct AssociatedKeys {
        static var currentCompletioObjectHandle = "currentCompletioObjectHandle"
    }
    typealias Completion = @convention(block) (UIViewController)->()
    var completionBlock:Completion?{
        get{
            let chBlock = unsafeBitCast(objc_getAssociatedObject(self, &AssociatedKeys.currentCompletioObjectHandle), Completion.self)
            return chBlock as Completion
        }set{
            if let newValue = newValue {
                let newValueObj : AnyObject = unsafeBitCast(newValue, AnyObject.self)
                objc_setAssociatedObject(self, &AssociatedKeys.currentCompletioObjectHandle, newValueObj, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            }
        }
    }
    func popToViewController(animated: Bool,comp:Completion){
        if (self.delegate == nil){
            self.delegate = self
        }
        completionBlock = comp
        self.popViewControllerAnimated(true)
    }
    func pushViewController(viewController: UIViewController, comp:Completion) {
        if (self.delegate == nil){
            self.delegate = self
        }
        completionBlock = comp
        self.pushViewController(viewController, animated: true)
    }

    public func navigationController(navigationController: UINavigationController, didShowViewController viewController: UIViewController, animated: Bool){
        if let comp = completionBlock{
            comp(viewController)
            completionBlock = nil
            self.delegate = nil
        }
    }
}

回答by nzeltzer

It takes a little more pipework to add this behavior and retain the ability to set an external delegate.

添加此行为并保留设置外部委托的能力需要更多的管道工作。

Here's a documented implementation that maintains delegate functionality:

这是一个维护委托功能的文档化实现：

LBXCompletingNavigationController

LBXCompletingNavigationController