• LZNavigationController

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

@interface LZNavigationController : UINavigationController

@end

// LZNavigationController.m
#import "LZNavigationController.h"

@interface LZNavigationController () <UIGestureRecognizerDelegate>


@end

@implementation LZNavigationController

+ (void)initialize
{
    // 1.拿到导航条
    UINavigationBar *bar = [UINavigationBar appearanceWhenContainedIn:self, nil];

    // 2.目的把导航条背景图片
    [bar setBackgroundImage:[UIImage imageNamed:@"navigationbarBackgroundWhite"] forBarMetrics:UIBarMetricsDefault];

    NSMutableDictionary * attr = [NSMutableDictionary dictionary];
    attr[NSFontAttributeName] = [UIFont boldSystemFontOfSize:20];
    [bar setTitleTextAttributes:attr];
}

- (void)viewDidLoad {
    [super viewDidLoad];

    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self.interactivePopGestureRecognizer.delegate action:@selector(handleNavigationTransition:)];
    // 把手势添加到view上
    [self.view addGestureRecognizer:pan];
    pan.delegate = self;

    // 尝试了一下,感觉下面这行代理没有什么用,不过最好不要省略,万一出现什么bug呢
    self.interactivePopGestureRecognizer.enabled = NO;
}

#pragma mark - UIGestureRecognizerDelegate方法
// 是否触发手势
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    // 根控制器下不要触发手势,让手势不起作用
    return self.childViewControllers.count > 1 ;
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    // 滑动返回功能为什么失效:用滑动手势做，验证滑动手势是否还在(验证之后还在)
    // 代理可以控制手势是否有效,验证:代理做了一些事情,导致滑动手势失效
    /**
     *  self.interactivePopGestureRecognizer =
        <UIScreenEdgePanGestureRecognizer: 0x7fa2d3c5c820; state = Possible; delaysTouchesBegan = YES; view = <UILayoutContainerView 0x7fa2d3ea5c60>; target= <(action=handleNavigationTransition:, target=<_UINavigationInteractiveTransition 0x7fa2d3c5c270>)>>

        self.interactivePopGestureRecognizer.delegate =
        <_UINavigationInteractiveTransition: 0x7fa7c372a850>    滑动手势代理
     */

    if (self.childViewControllers.count != 0) { // 非根控制器

        viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem itemWithTarget:self action:@selector(back) image:@"navigationButtonReturn" highImage:@"navigationButtonReturnClick" color:[UIColor blackColor] highColor:[UIColor redColor] title:@"返回"];

        self.hidesBottomBarWhenPushed = YES;
    }

    [super pushViewController:viewController animated:YES];
}

- (void)back
{
    [self popViewControllerAnimated:YES];
}

@end