ios:UIAlertView自動消失

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在寫程式的過程中用到很多提示的資訊，於是非常自然地就要使用UIAlertView控制項。但是這些提示的資訊有時候只需提示就行，不用操作，那麼此時就要這個提示框自動消失就OK了。 UIAlertView彈出後2s讓其自動消失，兩種方法： (1)結合NSTimer

 定義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];

}