重写系统中的UINavigationController 返回按钮的事件

.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
 
.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 < .) {
[UIView animateWithDuration:. animations:^{
subview.alpha = .;
}];
}
}
}
 
return NO;
}
 
@end
 
.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
 
}
 
参考:http://blog.csdn.net/a330416020/article/details/41700821