iOS重写系统中的UINavigationController返回按钮的事件

来源：互联网发布：索尼耳机知乎编辑：程序博客网时间：2024/05/21 06:35

以下主要帮助朋友们监听iOS系统的UINavigationController返回按钮的事件，主要有两种方案

第一种方案就是大家都能想到的，也是最简单的，代码如下：

-(void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:animated];}

因为，点击导航条的返回按钮后，首先触发的事件就是当前页面消失，变得不可见，这确实是一个行之有效的方案。

第二种方案就是重写系统中的UINavigationController返回按钮监听事件，具体代码和实现说明如下：

1.扩展UIviewControllerUIViewController+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>@endUIViewController+BackButtonHandler.m文件 #import "UIViewController+BackButtonHandler.h"@implementation UIViewController (BackButtonHandler)@end2.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 /34452906for(UIView *subview in [navigationBar subviews]) {if(subview.alpha < 1.) {[UIView animateWithDuration:.25 animations:^{subview.alpha = 1.;}];}}}return NO;}@end3.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}

具体怎么选择看个人需要，希望能帮助到各位！

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