ios - 如果使用自动布局，何时检查呈现的 viewController 是否属于类型

Question

这是我用来在 viewDidLoad 中设置约束的代码:

if (self.presentingViewController?.isKindOfClass(GameViewController) != nil) {
    print("huhu")
    self.bottomViewToBottomConstraint.constant = -367
    self.bottomViewToHiddenButtonConstraint.constant = 401
} else {
    self.bottomViewToBottomConstraint.constant = -200
    self.bottomViewToHiddenButtonConstraint.constant = 200
    print("No presenting viewController")
}

我收到的消息是没有显示 viewController。如您所见，我还设置了不同的动画约束，具体取决于呈现 viewController 的类。那么在什么时候已经知道谁在展示 View Controller 并且也是设置约束的正确时间呢？感谢帮助

Answer 1

就这么简单:

After you add the bottomView to it's superview.

试试 viewWillAppear 方法:

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    // here
}