现象
在使用iOS导航栏时踩上的一些坑，假设两个UIViewController：A、B，B是A的子级视图控制器
原因及解决方法
推荐使用- (instancetype)initWithCustomView:(UIView *)customView;来自定义不同的样子；但是如果只是想去掉backBarButtonItem，则可以使用一个空的UIBarButtonItem来替换
self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStyleDone target:nil action:nil];
补充：如果不修改内容，就是装饰一下文本，可以使用setTitleTextAttributes:forState:
重定义的返回键标题重叠，涉及到leftBarButtonItem，这个的使用场景有点像淘宝和微信的文章，使用在导航栏左侧需要多个按钮时，比如‘Back’、‘Close’多个并列存在的情况，也可以用leftBarButtonItem来设置为一个返回键，但是需要设置backBarButtonItem为空或使用hidesBackButton隐藏 (2017.09.04修改)，不然会出现两个标题重叠的情况，leftBarButtonItem的设置方法参考backBarButtonItem的设置方法，还可以批量设置多个，使用leftBarButtonItems。
继承UIViewController重写导航栏，继承UIViewController，自定义一个导航栏，隐藏系统的导航栏，然后在需要导航栏的地方用一句代码实现创建导航栏。
如我使用过的一个：QHBasicViewController（来源已不可考）
QHBasicViewController.h
#import <UIKit/UIKit.h>
@interface QHBasicViewController : UIViewController
@property (nonatomic, strong) UILabel* navTitleLabel;///导航栏标题
@property (nonatomic, strong, readonly) UIView *navView;///导航栏,只读
@property (nonatomic, strong) UIImageView* navBackgroundView;///导航栏背景
@property (nonatomic, strong, readonly) UIView* leftV;///导航栏左侧View，只读
@property (nonatomic, strong, readonly) UIView *rightV;///导航栏右侧View，只读
/** 创建导航栏
* @param szTitle 导航栏标题
* @param menuItem block回调，需要在这里定义导航栏上的各个按钮
- (void)createNavWithTitle:(NSString *)szTitle createMenuItem:(UIView *(^)(int nIndex))menuItem;
QHBasicViewController.m
#import "QHBasicViewController.h"
#import "HHUtil.h"
#define StatusbarHeight ((isIos7 >= 7 && __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1)?20.f:0.f)
#pragma mark - QHBasicViewController
@interface QHBasicViewController ()
@implementation QHBasicViewController
- (void)viewWillAppear:(BOOL)animated
//隐藏UIViewController的导航栏
[[self navigationController] setNavigationBarHidden:YES];
[super viewWillAppear:TRUE];
- (void)viewDidLoad
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
- (void)createNavWithTitle:(NSString *)szTitle createMenuItem:(UIView *(^)(int nIndex))menuItem
const CGFloat screenWidth = [[UIScreen mainScreen] bounds].size.width;
const CGFloat navigationViewHeigth = 44.f;
const CGFloat _nSpaceNavY = (isIos7 >= 7 && __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1) ? 0 : 20;
UIImageView *navIV = [[UIImageView alloc] initWithFrame:CGRectMake(0, _nSpaceNavY, screenWidth, 64 - _nSpaceNavY)];
[navIV setImage:[UIImage imageNamed:@"bg_nav.png"]];
_navBackgroundView = navIV;
[self.view addSubview:navIV];
/* { 导航条 } */
_navView = [[UIImageView alloc] initWithFrame:CGRectMake(0.f, StatusbarHeight, screenWidth, navigationViewHeigth)];
((UIImageView *)_navView).backgroundColor = [UIColor clearColor];
[self.view addSubview:_navView];
_navView.userInteractionEnabled = YES;
if (szTitle != nil)
UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake((_navView.bounds.size.width - 240)/2, (_navView.bounds.size.height - 40)/2, 240, 40)];
[titleLabel setText:szTitle];
[titleLabel setTextAlignment:NSTextAlignmentCenter];
[titleLabel setTextColor:[UIColor whiteColor]];
[titleLabel setFont:[UIFont boldSystemFontOfSize:18]];
[titleLabel setBackgroundColor:[UIColor clearColor]];
titleLabel.numberOfLines = 2;
_navTitleLabel = titleLabel;
[_navView addSubview:_navTitleLabel];
UIView *item1 = menuItem(0);
if (item1 != nil)
_leftV = item1;
[_navView addSubview:item1];
UIView *item2 = menuItem(1);
if (item2 != nil)
_rightV = item2;
[_navView addSubview:item2];
在创建你自己的UIViewController的时候，需要做的就是继承QHBasicViewController而不是UIViewController，然后在viewDidLoad的时候createNavWithTitle: createMenuItem:创建导航栏，然后在块回调中定义你自己的按钮。
继承UINavigationController重写push方法，继承UINavigationController方法，重写push方法，在push前后统一修改backBarButtonItem、leftBarButtonItem和rightBarButtonItem，甚至其它的导航栏设置，比如自定义titleView，导航栏背景之类的。
奉上个人做的一个例子：
HHNavigationController.h
#import <UIKit/UIKit.h>
@interface HHNavigationController : UINavigationController
/** 重载的initWithRootViewController:方法，附带初始化导航栏
* @param rootViewController 视图控制器
- (instancetype)initWithRootViewController:(UIViewController *)rootViewController;
HHNavigationController.m
#import "HHNavigationController.h"
#import <MediaPlayer/MediaPlayer.h>
@interface HHNavigationController ()<UIGestureRecognizerDelegate>
@property (nonatomic, strong) UIBarButtonItem *backBarButtonItm;
@implementation HHNavigationController
- (instancetype)initWithRootViewController:(UIViewController *)rootViewController
self = [super initWithRootViewController:rootViewController];
if (self) {
//设置导航栏和状态栏字体颜色为白色，导航栏背景设置为绿色
rootViewController.navigationController.navigationBar.barTintColor = RGBA(129, 164, 128, 1);//导航栏为绿色
rootViewController.navigationController.navigationBar.barStyle = UIBarStyleBlack;//状态栏字体为白色
rootViewController.navigationController.navigationBar.translucent = NO;//导航栏不透明
//设置侧滑滑动返回
self.interactivePopGestureRecognizer.delegate = self;
return self;
- (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 - action
-(void)onBack
[self popViewControllerAnimated:YES];
#pragma mark - back button
-(UIBarButtonItem *)backBarButtonItm
if (!_backBarButtonItm) {
UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom];
backBtn.frame = CGRectMake(0, 0, 30, 30);
[backBtn setImage:[UIImage imageNamed:@"btn_back"] forState:UIControlStateNormal];
[backBtn addTarget:self action:@selector(onBack) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *backBarItm = [[UIBarButtonItem alloc] initWithCustomView:backBtn];
_backBarButtonItm = backBarItm;
return _backBarButtonItm;
#pragma mark - Override
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
viewController.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:nil style:UIBarButtonItemStyleDone target:nil action:nil];//返回键置空
[super pushViewController:viewController animated:animated];
if (viewController.navigationItem.leftBarButtonItem == nil && [self.viewControllers count] > 1) {
//设置返回键
viewController.navigationItem.leftBarButtonItem = self.backBarButtonItm;
//设置导航栏和状态栏字体颜色为白色，导航栏背景设置为绿色
viewController.navigationController.navigationBar.barTintColor = RGBA(129, 164, 128, 1);//导航栏为绿色
viewController.navigationController.navigationBar.barStyle = UIBarStyleBlack;//状态栏字体为白色
viewController.navigationController.navigationBar.translucent = NO;//导航栏不透明
原生的导航栏虽然方便，但是牺牲了很多便利，自定义起来比较麻烦，特别是如果要求动画的话（这个需求很正常），基本就用不了只能自己写一个伪导航栏来替代
不容易统一，如果使用present方法，呈现的方式都不同，也不会有导航栏，虽然有方法加导航栏，但是还是有差异，也容易给代码的编写造成困扰