1.擴展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.擴展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 ///在這個方法里寫返回按鈕的事件處理
{
//這里寫要處理的代碼
[self.navigationController popViewControllerAnimated:YES];
return YES;//返回NO 不會執(zhí)行
}
