Iphone 如何通过动画隐藏视图上的内容

我正在显示一个视图，其中有一个按钮。单击此按钮，我将通过Objective C中定义的动画方法显示一个弹出视图，并在弹出视图上添加一个图像。然后在视图上的任何点击，此弹出视图通过将其宽度和高度设置为零而隐藏，但其上的图像不隐藏。我如何隐藏它。。？ 这些是我正在使用的方法

单击按钮后调用此方法

-(void)btnImageClkForPopUp:(id)sender
{  
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2.5];
popup_viewforimage.frame=CGRectMake(8, 30, 300, 250);
popup_viewforimage.backgroundColor=[UIColor whiteColor];

UIImageView *imgview=[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 300, 250)];
imgview.image=[UIImage imageNamed:@"apple.jpeg"];
[popup_viewforimage addSubview:imgview];

[self.view addSubview:popup_viewforimage];   
[UIView commitAnimations];
}

这两个方法在点击视图后被调用以隐藏此内容

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
if ([touch.view isKindOfClass:[UIButton class]])
{ 
 return NO;
}
return YES;   
}

-(void)hidekeyboard
{
 [UIView beginAnimations:nil context:nil];
 [UIView setAnimationDuration:2.5];
 popup_viewforimage.frame=  CGRectMake(15, 65, 0, 0);
 popup_viewforimage.backgroundColor=[UIColor grayColor];
 [self.view addSubview:popup_viewforimage];
  [UIView commitAnimations]; 
}

使用

或

将它的alpha设置为0

popup_viewforimage.alpha=0.0;

popup_viewforimage.alpha=0.0;

for (UIView *vw in popup_viewforimage.subviews) {
    if ([vw isKindOfClass:[UIImageView class]]) {
        vw.hidden=YES;
    }
}