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IOS 改变系统导航栏自带的返回action事件

#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


#import "UIViewController+BackButtonHandler.h"


@implementation UIViewController (BackButtonHandler)


@end


@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



#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

{

[self.navigationController popViewControllerAnimated:YES];

    return YES;

}



IOS 改变系统导航栏自带的返回action事件