自定义NavigationController的一般过程

iOS NavigationController侧滑返回失效。

用leftBarButtonItem自定义返回按钮后, 侧滑手势会失效.

UIButton *backButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 20, 44)];
[backButton setImage:[UIImage imageNamed:@"nav_back"] forState:UIControlStateNormal];
[backButton addTarget:self action:@selector(onBackButtonClicked) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:backButton];
self.navigationItem.leftBarButtonItem = item;

侧滑失效解决方案

新建类继承自UINavigationController

#import "VCNavigationController.h"

@interface VCNavigationController () 

@property (nonatomic, strong) UIViewController *viewController;

@end

@implementation VCNavigationController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark -- rewrite father method

- (instancetype)initWithRootViewController:(UIViewController *)rootViewController{
    VCNavigationController *nav = [super initWithRootViewController:rootViewController];
    nav.interactivePopGestureRecognizer.delegate = self;
    nav.delegate = self;
    return nav;
}

#pragma mark -- UINavigationControllerDelegate

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
    if(1 == navigationController.viewControllers.count){
        self.viewController = nil;
    }else{
        self.viewController = viewController;
    }
}

#pragma mark -- UIGestureRecognizerDelegate

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{
    if(gestureRecognizer == self.interactivePopGestureRecognizer){
        return self.viewController = self.topViewController;
    }
    return YES;
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    if([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]] && [otherGestureRecognizer isKindOfClass:[UIScreenEdgePanGestureRecognizer class]]){
        return YES;
    }else{
        return NO;
    }
}

@end

默认情况下，两个gesture recognizers不会同时识别它们的手势,但是你可以实现UIGestureRecognizerDelegate协议中的gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:方法对其进行控制。这个方法在这两个gesture recognizers中的任意一个将block另一个的触摸事件时调用，如果返回YES,则两个gesture recognizers可同时识别，如果返回NO，则并不保证两个gesture recognizers必不能同时识别，因为另外一个gesture recognizer的此方法可能返回YES。也就是说两个gesture recognizers的delegate方法只要任意一个返回YES，则这两个就可以同时识别；只有两个都返回NO的时候，才是互斥的。默认情况下是返回NO。

有这样一个例子，如果要侦测在window上的所有触摸事件，可以将gesture recognizer关联到window上，默认情况下如果手势被window识别，则子视图中的gesture recognizer就失效了，而我们在window上的gesture recognizer的目的只是监控所有事件，但并不处理这些事件，具体事件的处理还需要子视图中的各个gesture recognizer去处理，这样我们可以实现window上绑定gesture recognizer的delegate方法，使gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:返回YES即可。

更高度的自定义，大家可以搜索一下CYNavigation。这个demo写的挺好的，源码简单易懂，看懂的话，直接集成到项目里就行了

GitHub地址：CYNavigation