iOS中UIAlertView3秒后消失的两种实现方法

- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. UIAlertView* alert = [[UIAlertView alloc]initWithTitle:nil message:@"此信息３秒后消失" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil, nil]; [alert show]; [self performSelector:@selector(dismissAlert:) withObject:alert afterDelay:3.0];}- (void)dismissAlert:(UIAlertView*)alert { if ( alert.visible ) {  [alert dismissWithClickedButtonIndex:alert.cancelButtonIndex animated:YES]; }}

UIAlertView baseAlert = nil;- (void) performDismiss: (NSTimer *)timer{ [baseAlert dismissWithClickedButtonIndex:0 animated:NO];//important [baseAlert release]; baseAlert = NULL;}  - (void) presentSheet{ baseAlert = [[UIAlertView alloc]         initWithTitle:@"Alert" message:@"/nMessage Message Message "         delegate:self cancelButtonTitle:nil        otherButtonTitles: nil]; [NSTimer scheduledTimerWithTimeInterval:2.0f target:self selector: @selector(performDismiss:)         userInfo:nil repeats:NO]; [baseAlert show];}

- (void) dimissAlert:(UIAlertView *)alert{ if(alert) {  [alert dismissWithClickedButtonIndex:[alert cancelButtonIndex] animated:YES];  [alert release]; }}- (void)showAlert{    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"title" message:@"message" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil]; [alert show]; [self performSelector:@selector(dimissAlert:) withObject:alert afterDelay:2.0];}