UINavigationController "pushViewController：animated"の完了ハンドラー？
UINavigationControllerを使用してアプリを作成し、次のView Controllerを表示しようとしています。 iOS5では、UIViewControllersを表示する新しい方法があります。
presentViewController:animated:completion:
今、私はなぜUINavigationControllerの完了ハンドラがないのかと尋ねます。ただあります
pushViewController:animated:
新しいpresentViewController:animated:completion:のような独自の完了ハンドラーを作成することは可能ですか？
他の最新のソリューションについては par's answer を参照
UINavigationControllerアニメーションはCoreAnimationを使用して実行されるため、コードをCATransaction内にカプセル化し、完了ブロックを設定することは理にかなっています。
Swift：
Swiftのように拡張機能を作成することをお勧めします
extension UINavigationController {
public func pushViewController(viewController: UIViewController,
animated: Bool,
completion: @escaping (() -> Void)?) {
CATransaction.begin()
CATransaction.setCompletionBlock(completion)
pushViewController(viewController, animated: animated)
CATransaction.commit()
}
}
使用法：
navigationController?.pushViewController(vc, animated: true) {
// Animation done
}
Objective-C
ヘッダー：
#import <UIKit/UIKit.h>
@interface UINavigationController (CompletionHandler)
- (void)completionhandler_pushViewController:(UIViewController *)viewController
animated:(BOOL)animated
completion:(void (^)(void))completion;
@end
実装：
#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
iOS 7以降のSwift
Swift 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() }
}
}
編集：私はSwift 3オリジナルの答えのバージョンを追加しました。このバージョンでは、Swift 2多くの人を混乱させたようです。
スウィフト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：
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()
}
)
}
}
parの答え （これはiOS9で動作する唯一のものでした）に基づきますが、よりシンプルで、他に行方不明があります（完了に至らない可能性があります）：
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()
}
}
}
現在、UINavigationControllerはこれをサポートしていません。ただし、使用できるUINavigationControllerDelegateがあります。
これを実現する簡単な方法は、UINavigationControllerをサブクラス化し、完了ブロックプロパティを追加することです。
@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
新しいView Controllerをプッシュする前に、完了ブロックを設定する必要があります。
UIViewController *vc = ...;
((PbNavigationController *)self.navigationController).completionBlock = ^ {
NSLog(@"COMPLETED");
};
[self.navigationController pushViewController:vc animated:YES];
この新しいサブクラスは、Interface Builderで割り当てるか、次のようにプログラムで使用できます。
PbNavigationController *nc = [[PbNavigationController alloc]initWithRootViewController:yourRootViewController];
@Klaasの回答（および this questionの結果）を拡張するために、Pushメソッドに完了ブロックを直接追加しました。
@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
次のように使用します。
UIViewController *vc = ...;
[(PbNavigationController *)self.navigationController pushViewController:vc animated:YES completion:^ {
NSLog(@"COMPLETED");
}];
Swift 4ポップ付きバージョンです。
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()
}
}
他の誰かがこれを必要とする場合に備えて。
IOS 7.0以降、UIViewControllerTransitionCoordinatorを使用してプッシュ完了ブロックを追加できます。
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");
}];
Swift 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
}
}
}
この動作を追加し、外部デリゲートを設定する機能を保持するには、もう少しパイプラインが必要です。
デリゲート機能を維持する文書化された実装は次のとおりです。