为什么多次调用viewDidLayoutSubviews? [英] Why is viewDidLayoutSubviews called multiple times?

问题描述

我正在使用Swift开发iOS通用应用程序，并使用自动布局功能，并且仅支持纵向模式.

I'm developing iOS Universal App with Swift, using auto layout and support only portrait.

我发现UIViewController.viewDidLayoutSubviews被多次调用.相反，viewDidLoad在启动MyApp的UIViewController时仅被调用一次.

I found UIViewController.viewDidLayoutSubviews called multiple times. Instead, viewDidLoad is only called once on starting up MyApp's UIViewController.

为什么多次调用viewDidLayoutSubviews?是否会按顺序对每个UIView(UIButtons，UITextFields等)进行约束?

Why is viewDidLayoutSubviews called multiple times? Will constraints on each UIView (UIButtons,UITextFields, etc..) be performed in order?

任何信息将不胜感激.

推荐答案

LoadView仅调用一次:需要加载视图时.

LoadView is only called once: when the view needs to be loaded.

LayoutSubviews一次-这包括每当将子视图添加到视图，滚动，调整大小等时.

LayoutSubviews, however, is called once per run loop on any view that has had setNeedsLayout or setNeedsDisplayInRect called on it - this includes whenever a subview has been added to the view, scrolling, resizing, etc.

这篇关于为什么多次调用viewDidLayoutSubviews?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！