拦截UIViewController的popViewController事件

实现拦截UIViewControllerpop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UINavigatonControllerCategory,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://*.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:

  • UIViewController当中引入头文件
#import "UIViewController+BackButtonHandler.h"
  • 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:

上一篇:C/C++程序员必须熟练应用的开源项目(转-清风小阁)


下一篇:low security dvwa--SQL Injection(Blind)