iPhone SDK:如何隐藏警告框？

Question

我使用以下代码来显示一个警告框：

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Info" message:@"My Message" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];  
[alert show];  
[alert release];

你能告诉我当手机改变方向时如何再次隐藏提示框吗？

Answer 1

首先，您必须在您的界面中保存对警报的引用。

@interface MyViewController : UIViewController {
    UIAlertView *alert;
}
@property (nonatomic, retain) IBOutlet UIAlertView *alert;

创建警报时，您将使用

self.alert = [[[UIAlertView alloc] initWithTitle:@"Info" message:@"My Message" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease];  
[alert show]; 

然后，您必须添加另一个方法didRotateFromInterfaceOrientation:

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
    [super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
    [alert dismissWithClickedButtonIndex:[alert cancelButtonIndex] animated:YES];
    self.alert = nil;
}