学习iOS自定义导航控制器UINavigationController

#import "BWNavigationController.h"
#import "UIBarButtonItem+Item.h"

@interface BaseNavigationController () <UIGestureRecognizerDelegate>

@end

@implementation BWNavigationController

+ (void)load {
  [super load];
  UINavigationBar *navigationBar = [UINavigationBar appearanceWhenContainedIn:self, nil];

  NSMutableDictionary *dict = [NSMutableDictionary dictionary];
  dict[NSFontAttributeName] = [UIFont boldSystemFontOfSize:20];
  [navigationBar setTitleTextAttributes:dict];

  [navigationBar setBackgroundImage:[UIImage imageNamed:@"navigationbarBackgroundWhite"] forBarMetrics:UIBarMetricsDefault];
}

- (void)viewDidLoad {
  [super viewDidLoad];
  // 屏幕边缘滑动(只能在屏幕的边缘才能触发该手势，不能在屏幕的任意一点触发该手势)
  UIScreenEdgePanGestureRecognizer *edgePanGestureRecognizer = (UIScreenEdgePanGestureRecognizer *)self.interactivePopGestureRecognizer;

  // 滑动手势（禁用系统自带的屏幕边缘滑动手势，使用自定义的滑动手势目的就是达到触摸屏幕上的任意一点向右滑动都能实现返回的效果）
  UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:edgePanGestureRecognizer.delegate action:@selector(handleNavigationTransition:)];
  panGestureRecognizer.delegate = self;
  [self.view addGestureRecognizer:panGestureRecognizer];

  // 禁用系统的屏幕边缘滑动手势
  edgePanGestureRecognizer.enabled = NO;
}

// 是否允许触发手势，如果是根视图控制器则不需要
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
  return self.childViewControllers.count > 1;
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
  // 统一设置返回按钮
  NSInteger count = self.childViewControllers.count;
  if (count > 0) {
    viewController.hidesBottomBarWhenPushed = YES;
    viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem backBarButtonItemWithImage:[UIImage imageNamed:@"navigationButtonReturn"] highlightImage:[UIImage imageNamed:@"navigationButtonReturnClick"] tagert:self action:@selector(back) title:@"返回"];
  }

  [super pushViewController:viewController animated:animated];
}

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