重写系统中的UINavigationController返回按钮的事件

1.扩展UIviewController

UIViewController+BackButtonHandler.h

#import <UIKit/UIKit.h>
@protocol BackButtonHandlerProtocol <NSObject> @optional // Override this method in UIViewController derived class to handle 'Back' button click -(BOOL)navigationShouldPopOnBackButton; @end @interface UIViewController (BackButtonHandler) <BackButtonHandlerProtocol> @end           

UIViewController+BackButtonHandler.m文件

#import "UIViewController+BackButtonHandler.h"

@implementation UIViewController (BackButtonHandler) @end           

2.扩展UINavigationController ,也可以继承 使用

@implementation UINavigationController (ShouldPopOnBackButton) - (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem*)item { if([self.viewControllers count] < [navigationBar.items count]) { return YES; } BOOL shouldPop = YES; UIViewController* vc = [self topViewController]; if([vc respondsToSelector:@selector(navigationShouldPopOnBackButton)]) { shouldPop = [vc navigationShouldPopOnBackButton]; } if(shouldPop) { dispatch_async(dispatch_get_main_queue(), ^{ [self popViewControllerAnimated:YES]; }); } else { // Workaround for iOS7.1. Thanks to @boliva - http://stackoverflow.com/posts/comments /34452906 for(UIView *subview in [navigationBar subviews]) { if(subview.alpha <            

3.测试使用

#import "ViewController.h
#import "UIViewController+BackButtonHandler.h"

@implementation ViewController -(void) viewDidLoad { [super viewDidLoad]; self.title = [NSString stringWithFormat:@"Screen-%d", self.navigationController.viewControllers.count]; self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Next" style:UIBarButtonItemStylePlain target:selfaction:@selector(onNextBtn:)]; } -(void) onNextBtn:(id)sender { [self.navigationController pushViewController:[ViewController new] animated:YES]; } -(BOOL) navigationShouldPopOnBackButton ///在这个方法里写返回按钮的事件处理 { //这里写要处理的代码 [self.navigationController popViewControllerAnimated:YES]; return YES;//返回NO 不会执行 }