本文介绍了将方法添加到UINavigationBar后退按钮？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
如何将方法添加到UINavigationbar后退按钮，所以每当我点击后退按钮时，我需要检查一些值并显示UIAlertView？有什么选择吗？
How can i add method to UINavigationbar back button, so whenever I click that back button I need to check some values and show UIAlertView? Is there any option for this?
我尝试过这种方法，但它适用于我
i tried this method but its working for me
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
//show alert
}
以及这种方法，但两者都没有工作
and also this method but both are not woking
-(void) viewWillDisappear:(BOOL)animated {
if ([self.navigationController.viewControllers indexOfObject:self]==NSNotFound) {
// back button was pressed. We know this is true because self is no longer
// in the navigation stack.
NSLog(@"hi");
}
推荐答案
是的你可以
在viedDidLoad中
Yes you canIn viedDidLoad
UIBarButtonItem * backBtn = [[UIBarButtonItem alloc]initWithTitle:@"Back" style:UIBarButtonItemStyleBordered target:self action:@selector(goBackToAllPets:)];
self.navigationItem.leftBarButtonItem = backBtn;
编写以下函数来检查条件
write following function to check condition
-(void)goBackToAllPets:(id)sender
{
if(/*check condition*/)
{
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:nil message:@"message" delegate:self cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil];
alert.tag = 0;
[alert show];
}
else
{
[self.navigationController popViewControllerAnimated:YES];
}
}
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