image.png
-(void)WCSetUpNavItem{
self.navigationItem.leftBarButtonItem = nil;//移除原有的统一定制的返回键
UIButton *LeftItem = [UIButton buttonWithType:UIButtonTypeSystem];
LeftItem.frame = CGRectMake(0, 0, 20, 20);
[LeftItem setBackgroundImage:[UIImage imageNamed:@"nav_fanhui"] forState:UIControlStateNormal];
[LeftItem addTarget:self action:@selector(BackBtnClick) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *customLeftItem = [[UIBarButtonItem alloc] initWithCustomView:LeftItem];
self.navigationItem.leftBarButtonItem = customLeftItem;
}
#pragma mark - 返回键点击
-(void)BackBtnClick{
[UIAlertView alertWithCallBackBlock:^(NSInteger buttonIndex) {
} title:@"提示" message:@"是否退出？" cancelButtonName:@"取消" otherButtonTitles:@"确定", nil];
}
实现拦截UIViewController的pop操作有两种方式：
自定义实现返回按钮，即设置UIBarButtonItem来实现自定义的返回操作。
创建UINavigatonController的Category，来定制navigationBar: shouldPopItem:的逻辑。
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：
#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(0. < subview.alpha && subview.alpha < 1.) {
[UIView animateWithDuration:.25 animations:^{
subview.alpha = 1.;
}];
}
}
}
return NO;
}
使用：
在UIViewController当中引入头文件
#import "UIViewController+BackButtonHandler.h"
在UIViewController中实现navigationShouldPopOnBackButton方法。
- (BOOL)navigationShouldPopOnBackButton{
[[[UIAlertView alloc] initWithTitle:@"提示" message:@"确定返回上一界面?"
delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"确定", nil] show];
//renturn no 拦截pop事件
return NO;
}
参考文献：
将navigationBar上的左边按钮移除
iOS拦截导航栏返回按钮事件的正确方式
UIViewController-BackButtonHandler
