iOS 加载storyboard和统一设置导航控制器返回按钮，

// 1.加载storyboard
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"storyboard名称" bundle:nil];
// 2.初始化箭头指向的控制器
xxxxViewController *xxVC = [storyboard instantiateInitialViewController];

// 系统手势代理
@property (nonatomic, strong) id popGesture;

self.popGesture = self.interactivePopGestureRecognizer.delegate;

// 想统一设置返回按钮，滑动移除控制器
// 清空手势代理就能实现滑动返回，iOS6不支持

// 当是跟控制器，还原代理，如果是非跟控制器，清空代理
self.delegate = self;

// 当控制器显示完毕的时候调用
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    if (self.viewControllers[0] == viewController) {
        // 根控制器
        // 还原代理
        self.interactivePopGestureRecognizer.delegate = self.popGesture;
    } else {
        // 非根控制器，清空代理
        self.interactivePopGestureRecognizer.delegate = nil;
    }
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
// 当非根控制器设置导航条左侧返回按钮
   if (self.viewControllers.count > 1) {
      // 设置导航条左侧返回按钮
      viewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage ImageNamed:@"XXX"] style:0 target:self action:@selector(back)];
   }
}
- (void)back {
   [self popViewControllerAnimated:YES];
}

// 设置导航条前景色
[bar setTintColor:[UIColor whiteColor]];

// 获取到导航条按钮的标识
UIBarButtonItem *item = [UIBarButtonItem appearanceWhenContainedIn:self, nil];
// 修改返回按钮标题的位置
[item setBackButtonTitlePositonAdjustment:UIOffsetMake(0, -100) forBarMetrics:UIBarMetricsDefault];

// 全屏滑动移除控制器
// 1.先修改系统的手势，系统没有给我们提供属性
UIScreenEdgePanGestureRecognizer *gest = self.interactivePopGestureRecognizer;

// 2.自己添加手势
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleNavigationTransition:)];
[self.view addGestureRecognizer:pan];

// 却Target 系统的私有属性
//  KVC  [gest valueForKeyPath:@""];
// 不知道 Target 真实类型
// OC runtime 机制 只能动态获取当前类的成员属性，不能获取其子类或者父类的属性<objc/runtime.h>
// __unsafe_unretained Class 要获取哪个类的成员属性
// unsigned int *outCount 获取Class 下面的所有成员属性的个数
unsigned int outCount = 0;
Ivar *ivars = class_copyIvarList([UIGestureRecognizer class], &outCount)
for (int i = 0; i < outCount; i++) {
    // 获取成员属性的名字
    NSString *name = @(ivar_getName(ivars[i]));
    NSLog(@"%@", name);
}
// _targets
 NSArray *targets = [gest valueForKeyPath:@"_targets"];
 NSLog(@"%@", targets[0]);
 id target = [targets[0] valueForKeyPath:@"_target"];

 UIPanGestureRecognizer *pan1 =  [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan)];
 [self.view addGestureRecognizer:pan1];
 pan1.delegate = self;

id target = self.interactivePopGestureRecognizer.delegate;

// 2.自己添加手势
// 禁止系统的手势
self.interactivePopGestureRecognizer.enabled = NO;

 UIPanGestureRecognizer *pan =  [[UIPanGestureRecognizer alloc] initWithTarget:target action:@selector(handleNavigationTransition:)];
 [self.view addGestureRecognizer:pan];


pan.delegate = self;

// 当开始滑动的时候就会调用 如果返回YES，可以滑动
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    // 当是根控制器不让移除(禁止),非根控制器允许移除控制器
    BOOL open = self.viewCintrollers.count > 1;
    return open;
}