使用 UIAlertView 检测按钮点击

Question

我试图在按下按钮时拨打电话并发出警报。我用这个：

-(IBAction)Add { 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"add button pressed"
                                                    message:@"Add to record"
                                                   delegate:nil     
                                          cancelButtonTitle:@"Cancel" 
                                          otherButtonTitles:@"OK", nil   ];
    [alert show];
    [alert release];    
} 

好的，没问题，出现了两个按钮，确定和取消。现在我想检测按下了我使用的哪个按钮：

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
    // the user clicked one of the OK/Cancel buttons
    if (buttonIndex == 0)
    {
       //just to show its working, i call another alert view
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"OK WORKIng well"
                                                        message:@"no error"                                                                                                            delegate:nil 
                                              cancelButtonTitle:@"IWORKS" 
                                              otherButtonTitles:@"NO PRB", nil];
        [alert show];
        [alert release];    


    }
    else
    {
        NSLog(@"cancel");       
    }
}

现在这就是问题所在。我无法检测到按下了哪个按钮；第二个警报视图不显示。我已经检查了代码几次，似乎没有任何问题。也没有错误/警告。

Answer 1

要检测按钮点击，警报视图必须有一个关联的委托，例如

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"add button pressed"
                                                message:@"Add to record"
                                               delegate:self    // <------
                                      cancelButtonTitle:@"Cancel"
                                      otherButtonTitles:@"OK", nil];

Answer 2

这是我使用的你的代码，也添加了一些我的代码。
**

-(IBAction) Add 
{

          UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"add button pressed"

                                                       message:@"Add to record"
                                                      delegate:nil     
                                             cancelButtonTitle:@"Cancel" 
                                             otherButtonTitles:@"OK", nil];

       alert.tag=101;//add tag to alert
       [alert show];
       [alert release];     
}

现在，当您按下警报按钮时，它将调用 clickedButtonAtIndex
但每个警报都应该有一个标识符。所以添加标签，然后

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex** 

{

//  the user clicked one of the OK/Cancel buttons
if(alertView.tag == 101)     // check alert by tag 
{    

if (buttonIndex == 0)

   {

    //just to show its working, i call another alert view

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle: @"OK WORKIng well"

                                                    message:@"no error"
                                                   delegate:nil
                                          cancelButtonTitle:@"IWORKS" 
                                          otherButtonTitles:@"NO PRB", nil];

    [alert show];
    [alert release];    

}

else

{
    NSLog(@"cancel");       
}
}
}

希望它有帮助。

Answer 3

0 的buttonIndex 是取消按钮。我建议使用：

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex == 0)
{
      NSLog(@"cancel");   
}
else
{
   UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"OK works" message:@"no error" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];                                                                                                              
    [alert show];
    [alert release];        
}
}

Answer 4

我觉得如果您希望在现有警报视图的按钮单击事件上显示新的警报视图，最好使用

- (void) alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{

}

委托方法而不是

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{

}

Answer 5

如果您希望代码更简洁并且不依赖于委托，则应该尝试 UIAlertView 的块实现：

https:// github.com/steipete/PSAlertView

不过，块仅在 iOS 4+ 设备上受支持。

Answer 6

1)
.h file 
@interface MyClassViewController:<UIAlertViewDelegate> 

2)
.m file

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Note"
                                                message:@"some message"
                                               delegate:self    // must be self to call clickedButtonAtIndex
                                      cancelButtonTitle:@"Cancel"
                                      otherButtonTitles:@"OK", nil];


3)
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {

  if (buttonIndex == [alertView cancelButtonIndex]) {
    NSLog(@"The cancel button was clicked from alertView");
  }
 else {

}
}