重写导航控制器的push方法，通过获取导航的代理方法来防止多次push界面的bug

.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface CoustomNavVC : UINavigationController

@end

NS_ASSUME_NONNULL_END

实现文件

#import "CoustomNavVC.h"

@interface CoustomNavVC () <UINavigationControllerDelegate>

@end

@implementation CoustomNavVC

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.delegate = self;
}

//支持旋转
-(BOOL)shouldAutorotate
{
    return [self.topViewController shouldAutorotate];
}

//支持的方向
- (UIInterfaceOrientationMask)supportedInterfaceOrientations
{
    return [self.topViewController supportedInterfaceOrientations];
}

//2019/9/5
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return [self.topViewController preferredInterfaceOrientationForPresentation];
}

//防止多次push同一个控制器
-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
     //这个方法是在当前控制器执行push的时候，禁止手势右划返回，避免出现crash的现象
    if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
        self.interactivePopGestureRecognizer.enabled = NO;
    }
    //判断上一个控制器和现在的控制器是不是同一个，如果是，返回。如果不是push到当前控制器，这就有效避免了同一个控制器连续push的问题
    if ([self.topViewController isMemberOfClass:[viewController class]]) {
        return;
    }
    [super pushViewController:viewController animated:animated];
}

-(void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
        self.interactivePopGestureRecognizer.enabled = YES;
    }
}