重寫push方法本文中達到的效果就是
self.viewControllers.count == 0，就是第一個頁面設置界面（第一個界面和其他的界面不一樣，不需要返回等鍵），下面的控制器可以是一個統一格式，當然，程序執行步驟是先執行push方法，然后才是各個控制器的[View didload]，所以當你下面的控制器想要其他的格式的時候可以在[View didload]的里面按需利用自己的東西覆蓋

//.h文件
#import <UIKit/UIKit.h>
@interface YLMainNavigationController : UINavigationController
@end

//.m文件
#import "YLMainNavigationController.h"
@implementation YLMainNavigationController
- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationBar.barTintColor = [UIColor colorWithRed:1 green:0.8 blue:0.8 alpha:1];
    //去除navigationBar下面的黑線
    self.navigationBar.barStyle = UIBaselineAdjustmentNone;
}
//導航控制器里面
-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{
    if (self.viewControllers.count == 0) {
        self.navigationBar.backgroundColor = [UIColor colorWithRed:0.345 green:0.624 blue:0.961 alpha:1];
        viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem itemWithTarget:self action:nil image:@"nav_home_logo" highLightImage:nil];;
        //掃碼
        viewController.navigationItem.rightBarButtonItem=[UIBarButtonItem itemWithTarget:self action:@selector(search) image:@"nav_home_sao" highLightImage:@"nav_home_sao"];
    }
    if (self.viewControllers.count > 0) {
        viewController.navigationItem.leftBarButtonItem=[UIBarButtonItem itemWithTarget:self action:@selector(back) image:@"nav_back" highLightImage:@"nav_back"];
        viewController.hidesBottomBarWhenPushed=YES;
    }

    [super pushViewController:viewController animated:YES];

}

-(void)search{
    NSLog(@"掃碼");
//[self popToRootViewControllerAnimated:YES];//回到根視圖
}
-(void)back{
    [self popViewControllerAnimated:YES];
}

寫一個UIBarButtonItem的Extension

//.h
#import <UIKit/UIKit.h>
@interface UIBarButtonItem (Extension)
+(UIBarButtonItem *)itemWithTarget:(id)target action:(SEL)action image:(NSString *)image highLightImage:(NSString *)highLightImage;
@end

//.m
#import "UIBarButtonItem+extension.h"
@implementation UIBarButtonItem (Extension)
+(UIBarButtonItem *)itemWithTarget:(id)target action:(SEL)action image:(NSString *)image highLightImage:(NSString *)highLightImage
{
    UIButton *btn=[[UIButton alloc]init];
    [btn addTarget:target action:action forControlEvents:UIControlEventTouchUpInside];
    [btn setBackgroundImage:[UIImage imageNamed:image] forState:UIControlStateNormal];
    [btn setBackgroundImage:[UIImage imageNamed:highLightImage] forState:UIControlStateHighlighted];
    CGSize size=btn.currentBackgroundImage.size;
    btn.frame=CGRectMake(0, 0, size.width, size.height);
    return [[UIBarButtonItem alloc]initWithCustomView:btn];
}
@end

趕快試試效果吧，自己添加rootViewController，然后看看導航上面的效果，試試就知道妙處
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