UIView layoutSubviews没有被调用 [英] UIView layoutSubviews not being called

问题描述

使用Xcode 4.2/iOS5.0

Using Xcode 4.2/iOS5.0

我有一个viewController和一个关联的viewController.xib.viewController被设置为.xib文件的所有者.它是从 UINavigationController 调用的.

I have a viewController and an associated viewController.xib. The viewController is set up as the .xib's file's owner. It is invoked from a UINavigationController.

当设备旋转纵向/横向时，我正在尝试一些手动布局

I am attempting some manual layout when the device is rotated portrait/landscape

据我了解，要覆盖的 UIView 方法是

As I understand it the UIView method to override is

- (void)layoutSubviews;

这是您进行布局的地方

但是-与 drawRect 一样，您不会直接调用它，它会在iOS适当的时候被调用

But - as with drawRect - you do not call this directly, it is invoked when appropriate by iOS

相反，您调用 setNeedsLayout ...

Instead you call setNeedsLayout...

所以我在ViewController中有这个

So I have this in the ViewController

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)
         fromInterfaceOrientation {
   [[self view] setNeedsLayout];
 }

在同一个ViewController中，我有这个

and in the same ViewController I have this

- (void)layoutSubviews {
    //.manual override of automatic layout on rotation
NSLog(@"layoutSubviews");
 }

但是 layoutSubviews 没有被调用，我也不明白为什么.

However layoutSubviews does not get called and I don't understand why.

这是一个线索...如果我直接将 layoutSubviews 称为 [self layoutSubviews]

Here is a clue... If I call layoutSubviews directly as [self layoutSubviews]

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)
         fromInterfaceOrientation {
   [self layoutSubviews];
 }

它会触发

但是，如果我将其称为 [[self view] layoutSubviews] ，则不会

But if I call it as [[self view] layoutSubviews] it does not

因此，视图及其控制器似乎未正确连接吗?

So it appears that the view and it's controller are not wired up correctly?

推荐答案

您的问题是，您已在视图控制器上而非视图上实现了 -layoutSubviews .永远不会这样称呼它. -layoutSubviews 是一种机制，通过该机制，自定义视图可以布局其自己的子视图(例如，具有图像的 UIImageView 的 UIButton 标签使用 UILabel ，并使用 -layoutSubviews 确保图像视图和标签均正确放置).这不是视图控制器可以控制其视图布局的机制.

Your problem here is you've implemented -layoutSubviews on your view controller, instead of on your view. It will never be called this way. -layoutSubviews is a mechanism by which a custom view can lay out its own subviews (e.g. a UIButton that has a UIImageView for the image and a UILabel for the label, and uses -layoutSubviews to ensure the imageview and label are all positioned correctly). It's not a mechanism by which a view controller can control the layout of its views.

如果要更改旋转的布局，则应该继续在 -didRotateFromInterfaceOrientation:内设置新的布局.

If you want to change layout on rotation, then you should just go ahead and set up the new layout inside of -didRotateFromInterfaceOrientation:.

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