Question

我有一个Navigation Controller，当我按下后退按钮时，我不想弹出视图，但我想显示UIAlertView。我只是想在制作后弹出视图选择UIAlertView！我能怎么做？我试图捕捉事件'后退按钮'，但没有结果：（

Answer 1

在 viewDidload 中创建一个UIBarButtonItem并将其添加到导航栏

UIBarButtonItem *backButton=[[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStyleBordered target:self action:@selector(backButtonClicked)];
self.navigationItem.leftBarButtonItem=backButton;

创建一个在单击backButton时调用的方法

-(void)backButtonClicked{
       UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Pop View!" message:@"Are you sure?" delegate:self cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil];
       [alert show];
}

编写此UIAlertView委托方法，该方法将在单击UIAlertView中的按钮时调用

-(void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex{
      if (buttonIndex==1) {
             [self.navigationController popViewControllerAnimated:YES];
      }
}

注意：不要忘记在头文件<UIAlertViewDelegate>

中添加UIAlertView委托

Answer 2

您可以使用此viewWillDisappear方法检查后退按钮（从here获取）：

-(void)viewWillDisappear:(BOOL)animated {
    if ([self.navigationController.viewControllers indexOfObject:self]==NSNotFound && self.isBackButtonPressed) {
        // back button was pressed.  We know this is true because self is no longer
        // in the navigation stack.
    }
    [super viewWillDisappear:animated];

希望这有帮助！

Answer 3

在UIAlertview委托方法中实现pop clickedButtonAtIndex：后退按钮需要实现仅显示UIAlertview

参考this

Answer 4

按照此代码

按钮操作。

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"Do you want to open?" delegate:self cancelButtonTitle:@"NO" otherButtonTitles:@"YES", nil];
[alert show];

//Alert View delegate method
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex==0)//NO
    {
        //your code
    }
    else if(buttonIndex==1)//YES
    {
        // your code
    }
}

如果是AlertView，请不要在Xcode中弹出导航控制器

4 个答案: