UIPickerView显示和隐藏的动画

    - (void)ViewAnimation:(UIView*)view willHidden:(BOOL)hidden {  
          
        [UIView animateWithDuration:0.3 animations:^{  
            if (hidden) {  
                view.frame = CGRectMake(0, [UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width, view.bounds.size.height);  
            } else {  
                [view setHidden:hidden];  
                view.frame = CGRectMake(0, [UIScreen mainScreen].bounds.size.height - view.bounds.size.height, [UIScreen mainScreen].bounds.size.width, view.bounds.size.height);  
            }  
        } completion:^(BOOL finished) {  
            [view setHidden:hidden];  
        }];  
    }