self.title = @"Title";[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];  self.navigationController.navigationBar.shadowImage = [UIImage new];  self.barImageView = self.navigationController.navigationBar.subviews.firstObject;  self.barImageView.alpha = 0;  //設置狀態欄  [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];  //設置標題顏色  self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor clearColor]};

-(void)scrollViewDidScroll:(UIScrollView *)scrollView {  CGFloat offset = scrollView.contentOffset.y;  //根據自己需要設置(136)的大小  CGFloat alpha = offset / 136;  _barImageView.alpha = alpha;  //記錄下當前的透明度,在返回當前頁面時需要  _alpha = alpha;  [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithFloat:alpha] forKey:@"_alpha"];  //設置標題的透明度  self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:alpha]};}

-(void)viewWillAppear:(BOOL)animated{  [super viewWillAppear:animated];  self.table.delegate = self;}-(void)viewDidAppear:(BOOL)animated {  BOOL isGesturePop = [[[NSUserDefaults standardUserDefaults] objectForKey:@"isGesturePop"] boolValue];  if (!isGesturePop) {    _barImageView.alpha = _alpha;    self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:_alpha]};  }  [super viewDidAppear:animated];}-(void)viewWillDisappear:(BOOL)animated{  [super viewWillDisappear:animated];  self.table.delegate = nil;  self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor blackColor]};  _barImageView.alpha = 1;  [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithBool:NO] forKey:@"isGesturePop"];}

@property (nonatomic, strong) NavigationInteractiveTransition *navT;

self.navigationController.interactivePopGestureRecognizer.enabled = NO;  UIGestureRecognizer *gesture = self.navigationController.interactivePopGestureRecognizer;  gesture.enabled = NO;  UIView *gestureView = gesture.view;  UIPanGestureRecognizer *popRecognizer = [[UIPanGestureRecognizer alloc] init];  popRecognizer.delegate = self;  popRecognizer.maximumNumberOfTouches = 1;  [gestureView addGestureRecognizer:popRecognizer];  _navT = [[NavigationInteractiveTransition alloc] initWithViewController:self.navigationController];  [popRecognizer addTarget:_navT action:@selector(handleControllerPop:)];

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {  //記錄當前是是否是通過手勢滑動回去  [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithBool:YES] forKey:@"isGesturePop"];  /**   * 這里有兩個條件不允許手勢執行，1、當前控制器為根控制器；2、如果這個push、pop動畫正在執行（私有屬性）   */  return self.navigationController.viewControllers.count != 1 && ![[self.navigationController valueForKey:@"_isTransitioning"] boolValue];}

#import <UIKit/UIKit.h>@class UIViewController, UIPercentDrivenInteractiveTransition;@interface NavigationInteractiveTransition : NSObject <UINavigationControllerDelegate>- (instancetype)initWithViewController:(UIViewController *)vc;- (void)handleControllerPop:(UIPanGestureRecognizer *)recognizer;- (UIPercentDrivenInteractiveTransition *)interactivePopTransition;@end

#import "NavigationInteractiveTransition.h"#import "PopAnimation.h"@interface NavigationInteractiveTransition ()@property (nonatomic, weak) UINavigationController *vc;@property (nonatomic, strong) UIPercentDrivenInteractiveTransition *interactivePopTransition;@property(nonatomic, strong) UIImageView *barImageView;@end@implementation NavigationInteractiveTransition- (instancetype)initWithViewController:(UIViewController *)vc{  self = [super init];  if (self) {    self.vc = (UINavigationController *)vc;    self.vc.delegate = self;  }  return self;}/** * 我們把用戶的每次Pan手勢操作作為一次pop動畫的執行 */- (void)handleControllerPop:(UIPanGestureRecognizer *)recognizer {  /**   * interactivePopTransition就是我們說的方法2返回的對象，我們需要更新它的進度來控制Pop動畫的流程，我們用手指在視圖中的位置與視圖寬度比例作為它的進度。   */  CGFloat progress = [recognizer translationInView:recognizer.view].x / recognizer.view.bounds.size.width;  [self.vc.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];  self.vc.navigationBar.shadowImage = [UIImage new];  self.barImageView = self.vc.navigationBar.subviews.firstObject;  CGFloat alpha = [[[NSUserDefaults standardUserDefaults] objectForKey:@"_alpha"] floatValue];  self.barImageView.alpha = 1 - progress > alpha ? alpha : 1 - progress;//  NSLog(@"===progress==%.2f",progress);  /**   * 穩定進度區間，讓它在0.0（未完成）～1.0（已完成）之間   */  progress = MIN(1.0, MAX(0.0, progress));  if (recognizer.state == UIGestureRecognizerStateBegan) {    /**     * 手勢開始，新建一個監控對象     */    self.interactivePopTransition = [[UIPercentDrivenInteractiveTransition alloc] init];    /**     * 告訴控制器開始執行pop的動畫     */    [self.vc popViewControllerAnimated:YES];  }  else if (recognizer.state == UIGestureRecognizerStateChanged) {    /**     * 更新手勢的完成進度     */    [self.interactivePopTransition updateInteractiveTransition:progress];  }  else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {    /**     * 手勢結束時如果進度大于一半，那么就完成pop操作，否則重新來過。     */    if (progress > 0.5) {      [self.interactivePopTransition finishInteractiveTransition];      self.barImageView.alpha = 0;;    }    else {      [self.interactivePopTransition cancelInteractiveTransition];    }    self.interactivePopTransition = nil;  }}- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController                 animationControllerForOperation:(UINavigationControllerOperation)operation                        fromViewController:(UIViewController *)fromVC                         toViewController:(UIViewController *)toVC {  /**   * 方法1中判斷如果當前執行的是Pop操作，就返回我們自定義的Pop動畫對象。   */  if (operation == UINavigationControllerOperationPop)    return [[PopAnimation alloc] init];  return nil;}- (id<UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController             interactionControllerForAnimationController:(id<UIViewControllerAnimatedTransitioning>)animationController {  /**   * 方法2會傳給你當前的動畫對象animationController，判斷如果是我們自定義的Pop動畫對象，那么就返回interactivePopTransition來監控動畫完成度。   */  if ([animationController isKindOfClass:[PopAnimation class]])    return self.interactivePopTransition;  return nil;}@end

#import <Foundation/Foundation.h>#import <UIKit/UIKit.h>@interface PopAnimation : NSObject <UIViewControllerAnimatedTransitioning>@end

#import "PopAnimation.h"@interface PopAnimation ()@property (nonatomic, strong) id <UIViewControllerContextTransitioning> transitionContext;@end@implementation PopAnimation- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext {  //這個方法返回動畫執行的時間  return 0.25;}/** * transitionContext你可以看作是一個工具，用來獲取一系列動畫執行相關的對象，并且通知系統動畫是否完成等功能。 */- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext {  /**   * 獲取動畫來自的那個控制器   */  UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];  /**   * 獲取轉場到的那個控制器   */  UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];  /**   * 轉場動畫是兩個控制器視圖時間的動畫，需要一個containerView來作為一個“舞臺”，讓動畫執行。   */  UIView *containerView = [transitionContext containerView];  [containerView insertSubview:toViewController.view belowSubview:fromViewController.view];  NSTimeInterval duration = [self transitionDuration:transitionContext];  /**   * 執行動畫，我們讓fromVC的視圖移動到屏幕最右側   */  [UIView animateWithDuration:duration animations:^{    fromViewController.view.transform = CGAffineTransformMakeTranslation([UIScreen mainScreen].bounds.size.width, 0);  }completion:^(BOOL finished) {    /**     * 當你的動畫執行完成，這個方法必須要調用，否則系統會認為你的其余任何操作都在動畫執行過程中。     */    [transitionContext completeTransition:!transitionContext.transitionWasCancelled];  }];}- (void)animationDidStop:(CATransition *)anim finished:(BOOL)flag {  [_transitionContext completeTransition:!_transitionContext.transitionWasCancelled];}@end