ios:UIAlertView自动消失

来自:cocoachina 在写程序的过程中用到很多提示的信息，于是非常自然地就要使用UIAlertView控件。但是这些提示的信息有时候只需提示就行，不用操作，那么此时就要这个提示框自动消失就OK了。
UIAlertView弹出后2s让其自动消失，两种方法： (1)结合NSTimer
定义UIAlertView *baseAlert;
- (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]; }
(2)使用PerformSelector：withObject：afterDelay：方法
- (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:nilotherButtonTitles:nil];
[alert show];
[self performSelector:@selector(dimissAlert:) withObject:alert afterDelay:2.0];
}