IOS / Objective-C：导航栏上的自定义Segue效果与Show Segue相比

Question

我有两个视图控制器，在这些控制器中，我使用常规的Show Segue（从右到左）沿一个方向运行，并使用定制的Segue（从左到右）沿另一个方向运行。我不认为我应该放松一下，因为任何一个VC都不从属于其他VC，并且使用这些设置意味着一个导航控制器可以管理事情。

在两个VC的左上角，我有一个包含个人资料照片的公共BarButton。

使用常规的从右到左顺序时，条形按钮上的个人资料照片保持不变。当屏幕的其余部分向内移动时，这看起来很棒，但是个人资料照片都留在原处。

但是，从另一个方向（从左到右），使用自定义序列，整个VC屏幕（包括导航栏）就会突然进入，您基本上会看到个人资料照片从左边缘进入，然后停留在正常的左栏中同一张照片稍早的位置。看起来不好。

是否可以在自定义segue期间强制导航栏中的公共元素停留在适当的位置，以更好地模仿系统show segue的行为？

预先感谢您的任何建议。

这是我的自定义序列代码：

#import "customSegue.h"
#import "QuartzCore/QuartzCore.h"

@implementation customSegue

-(void)perform {

    UIViewController *destinationController = (UIViewController*)[self destinationViewController];

    UIViewController *sourceViewController = (UIViewController*)[self sourceViewController];
    CGFloat animationDuration = .40;  
    transition.duration = animationDuration;
    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];
    transition.type = kCATransitionMoveIn;  
    transition.subtype = kCATransitionFromLeft;  

    [sourceViewController.navigationController.view.layer addAnimation:transition
                                                                forKey:kCATransition];

    UIColor *previousWindowBackgroundColor = sourceViewController.view.window.backgroundColor;

    sourceViewController.view.window.backgroundColor = destinationController.view.backgroundColor;


    [sourceViewController.navigationController pushViewController:destinationController animated:NO];
    // switch the window color back after the transition duration from above
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(animationDuration * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        // make sure we still have a handle on the destination controller
        if (destinationController) {
            destinationController.view.window.backgroundColor = previousWindowBackgroundColor;
        }
    });

}

@end

Answer 1

再次问好@ user6631314

我认为您不会通过使用CATransition进行应用并将其附加到navigationController视图的图层上来获得想要的东西。

相反，我建议将presentingViewController委托为UINavigationController的代表，并为LTR推送滚动您自己的逻辑（使用导航栏会更加顺畅，并且您不必再为过渡期间的黑栏担心）我以前的回复帮助您解决/解决方法。

因此，您需要将呈现视图控制器（或某些协调器视图控制器）设置为UINavigationControllerDelegate并实现此方法：

- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                                  animationControllerForOperation:(UINavigationControllerOperation)operation
                                               fromViewController:(UIViewController*)fromVC
                                                 toViewController:(UIViewController*)toVC

在该方法中，您将需要检查操作是否为UINavigationControllerOperationPush，如果是，则返回符合UIViewControllerAnimatedTransitioning协议的NSObject的子类（否则返回nil以允许所有其他导航操作作为标准）。在该类中，您将处理自定义导航控制器的推送动画覆盖。

LTR推式动画的基本逻辑是，您要在屏幕左侧向左启动toView，然后对其进行动画处理，以使其在动画持续时间（从代码开始为0.4）之后完全显示在屏幕上-因此启动将x位置偏移到视图宽度的负值（因此它完全不在屏幕上），然后在动画过程中将x位置设置为0（或者您可以+ =视图的宽度）。

这是当前自定义segue实现的外观示例（请注意导航栏也会滑过，这是您要在此处发布的问题）：

以及使用自定义动画控制器的过渡：

这是完整的代码：

#import "ViewController.h"
#import "LTRPushAnimator.h"

@interface ViewController () < UINavigationControllerDelegate>
@property (strong, nullable) UIView *profileView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationController.delegate = self;
    self.navigationItem.hidesBackButton = YES;
    self.profileView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
    UIImageView *profileImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Homer.jpg"]];
    [profileImageView setFrame:CGRectMake(0, 0, 40, 40)];
    profileImageView.layer.cornerRadius = 20.0f;
    profileImageView.layer.masksToBounds = YES;
    profileImageView.clipsToBounds = YES;
    profileImageView.layer.borderColor = [UIColor blackColor].CGColor;
    profileImageView.layer.borderWidth = 1.0f;
    [self.profileView addSubview:profileImageView];
    UIBarButtonItem *lbi = [[UIBarButtonItem alloc] initWithCustomView:self.profileView];
    self.navigationItem.leftBarButtonItem = lbi;
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
}

- (IBAction)pushFakeViewController:(id)sender {
    UIViewController *fakeViewController = [[UIViewController alloc] init];
    fakeViewController.view.backgroundColor = [UIColor redColor];
    UIBarButtonItem *lbi = [[UIBarButtonItem alloc] initWithCustomView:self.profileView];
    fakeViewController.navigationItem.leftBarButtonItem = lbi;
    fakeViewController.navigationItem.hidesBackButton = YES;
    [self.navigationController pushViewController:fakeViewController animated:YES];
    // this is just in here to pop back to the root view controller since we removed the back button, it can be removed obviously
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self.navigationController popViewControllerAnimated:YES];
    });
}

- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                                  animationControllerForOperation:(UINavigationControllerOperation)operation
                                               fromViewController:(UIViewController*)fromVC
                                                 toViewController:(UIViewController*)toVC
{
    if (operation == UINavigationControllerOperationPush) {
        return [[LTRPushAnimator alloc] init];
    }
    // otherwise standard animation
    return nil;
}

@end

LTRPushAnimator.h

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface LTRPushAnimator : NSObject <UIViewControllerAnimatedTransitioning>

@end

NS_ASSUME_NONNULL_END

LTRPushAnimator.m

#import "LTRPushAnimator.h"

@implementation LTRPushAnimator

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 0.4;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    [self _animatePushByFrameWithContext:transitionContext];
}

- (void)_animatePushByFrameWithContext:(id<UIViewControllerContextTransitioning>)transitionContext {
    UIViewController *toViewController   = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    CGRect toVCFrame = toViewController.view.frame;
    CGFloat viewWidth = toVCFrame.size.width;
    toVCFrame.origin.x -= viewWidth;
    [toViewController.view setFrame:toVCFrame];
    [[transitionContext containerView] addSubview:toViewController.view];
    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        CGRect finalVCFrame = toViewController.view.frame;
        finalVCFrame.origin.x = 0;
        [toViewController.view setFrame:finalVCFrame];
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

@end