ios捕获异常

@try 

{ 

Statements 

} 

@catch (NSException *ex) { 

        UIAlertView *alert = [[UIAlertView alloc] 

                                     initWithTitle:[ex name] 

                                     message:[ex reason] 

                                     delegate:self 

                                     cancelButtonTitle:@"OK" 

                                     otherButtonTitles: nil]; 

                                     [alert show]; 

}