以下主要幫助朋友們監聽iOS系統的UINavigationController返回按鈕的事件，主要有兩種方案

第一種方案就是大家都能想到的，也是最簡單的，程式碼如下：

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

第二種方案就是重寫系統中的UINavigationController返回按鈕監聽事件，具體程式碼和實現說明如下：

1.擴充套件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檔案

 #import "UIViewController+BackButtonHandler.h"

@implementation UIViewController (BackButtonHandler)

@end
2.擴充套件UINavigationController ,也可以繼承 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 < 1.) {
[UIView animateWithDuration:.25 animations:^{
subview.alpha = 1.;
}];
}
}
}

return NO;
}

@end
3.測試使用

#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 ///在這個方法裡寫返回按鈕的事件處理
{

//這裡寫要處理的程式碼
 [self.navigationController popViewControllerAnimated:YES];
return YES;//返回NO 不會執行

}