Question

我创建了一个UIview作为子视图，我想从中心显示和隐藏此视图，问题是帧更改在autolayout中不起作用，这是我的代码，但我想在autolayout中做，我知道nslayout常量以编程方式更改请给我解决方案。 -

(IBAction)click_button1:(id)sender
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    pop_view.alpha = 0;
    pop_view.frame = CGRectMake (screenRect.size.width/2, screenRect.size.height/2, 0, 0);

    pop_view.hidden = false;

    [UIView animateWithDuration:1.0 animations:^ {
        pop_view.alpha = 1.0;

      // pop_view.frame = CGRectMake (screenRect.size.width/2, screenRect.size.height/2, screenRect.size.width - 20, screenRect.size.height/2);


     pop_view.frame =  CGRectMake
        (
         ( self.view.frame.size.width  / ( CGFloat )2 ) - ( pop_view.frame.size.width  / ( CGFloat )2 ),
         ( self.view.frame.size.height / ( CGFloat )2 ) - ( pop_view.frame.size.height / ( CGFloat )2 ),
         pop_view.frame.size.width,
         pop_view.frame.size.height
         );
    }];


}

Answer 1

将pop_view放在视图的中心，方法是在容器中水平放置，在容器约束中垂直放置。

然后为pop_view提供尾随和前导约束和高度。在(IBAction)click_button1:(id)sender中，您可以根据需要隐藏或取消隐藏视图。

Answer 2

您似乎已在当前视图中添加pop_view并将其隐藏

如果您只想将pop_view。

居中

以编程方式它将是这样的：

 .... other declaration ...
 pop_view = popView(); // how ever you instantiate it
 pop_view.translatesAutoresizingMaskIntoConstraints = NO;
 [self.view addSubview:pop_view]; // or whatever your current view is

 // add the constraint to center it horizontally
 [self.view addConstraint:[NSLayoutConstraint constraintWithItem: pop_view
                                                       attribute: NSLayoutAttributeCenterX
                                                       relatedBy: NSLayoutRelationEqual 
                                                          toItem: self.view 
                                                       attribute: NSLayoutAttributeCenterX
                                                      multiplier: 1
                                                        constant: 0]];

 // Add the constraint to center it vertically
 [self.view addConstraint:[NSLayoutConstraint constraintWithItem: pop_view
                                                       attribute: NSLayoutAttributeCenterY
                                                       relatedBy: NSLayoutRelationEqual 
                                                          toItem: self.view 
                                                       attribute: NSLayoutAttributeCenterY
                                                      multiplier: 1
                                                        constant: 0]];

然后在您的IBAction中，您可以执行隐藏/显示操作

IOS UIVIEW在自动布局中从中心打开为POPUP

2 个答案: