-systemLayoutSizeFittingSize:在iOS 8下为tableHeaderView返回不正确的高度 [英] -systemLayoutSizeFittingSize: returning incorrect height for tableHeaderView under iOS 8

问题描述

关于使用自动布局正确调整tableHeaderView大小的众多线程(

There are numerous threads about correctly sizing a tableHeaderView with auto-layout (one such thread) but they tend to pre-date iOS 8.

我遇到了很多表视图和标题的情况，该视图在iOS 7下大小正确，但在iOS 8下使用前面提到的大多数线程拥护的代码却不正确.在表的控制器中，我有以下方法:

I have a situation with numerous table views, all with headers, that size correctly under iOS 7 but incorrectly under iOS 8 using the code that most of the aforementioned threads champion. In the controllers for the tables, I have the following method:

- (void)rejiggerTableHeaderView
{
    self.tableView.tableHeaderView = nil;

    UIView *header = self.headerView;

    [header setNeedsLayout];
    [header layoutIfNeeded];

    CGFloat height = [header systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    CGRect headerFrame = header.frame;
    headerFrame.size.height = height;

    header.frame = headerFrame;

    self.tableView.tableHeaderView = header;
}

在iOS 7下使用多行标签，这样可以正确调整表格视图标题的大小，如下所示:

With a multi-line label under iOS 7, this correctly sizes the table view's header like so:

但是在iOS 8下运行的相同代码会产生以下结果:

But the same code run under iOS 8 produces the following:

获取-systemLayoutSizeFittingSize:在iOS 8下返回正确大小的诀窍是什么? 这是一个演示问题的示例项目.

What's the trick to getting -systemLayoutSizeFittingSize: to return the correct size under iOS 8? Here's a sample project that demonstrates the issue.

推荐答案

将headerview函数更改为以下对我有用的东西:

Changing your headerview function to the following works for me:

- (void)rejiggerTableHeaderView
{
    self.tableView.tableHeaderView = nil;

    UIView *header = self.headerView;
    CGRect frame = header.frame;
    frame.size.width = self.tableView.frame.size.width;
    header.frame = frame;

    [header setNeedsLayout];
    [header layoutIfNeeded];

    CGFloat height = [header systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    CGRect headerFrame = header.frame;
    headerFrame.size.height = height;

    header.frame = headerFrame;

    self.tableView.tableHeaderView = header;
}

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