Question

我的应用程序创建了一个UITableViewController，它包含一个可能具有任意高度的自定义tableHeaderView。我一直在努力设置动态设置此标头，因为似乎建议的方法是缩短此标头。我的UITableViewController的相关代码：

import UIKit
import SafariServices

class RedditPostViewController: UITableViewController, NetworkCommunication, SubViewLaunchLinkManager {

    //MARK: UITableViewDataSource
    var post: PostData?
    var tree: CommentTree?
    weak var session: Session! = Session.sharedInstance

    override func viewDidLoad() {
        super.viewDidLoad()

        // Get post info from api
        guard let postData = post else { return }

        //Configure comment table
        self.tableView.registerClass(RedditPostCommentTableViewCell.self, forCellReuseIdentifier: "CommentCell")

       let tableHeader = PostView(withPost: postData, inViewController: self)
       let size = tableHeader.systemLayoutSizeFittingSize(UILayoutFittingExpandedSize)
       let height = size.height
       let width = size.width
       tableHeader.frame = CGRectMake(0, 0, width, height)
       self.tableView.tableHeaderView = tableHeader


       session.getRedditPost(postData) { (post) in
           self.post = post?.post
           self.tree = post?.comments
           self.tableView.reloadData()
       }
    }
}

这会导致以下错误的布局：

如果我将行tableHeader.frame = CGRectMake(0, 0, width, height)更改为tableHeader.frame = CGRectMake(0, 0, width, 1000)，则tableHeaderView将正确显示：

我不确定我在这里做错了什么。另外，自定义UIView类，如果这有帮助：

import UIKit
import Foundation

protocol SubViewLaunchLinkManager: class {
    func launchLink(sender: UIButton)
}

class PostView: UIView {

    var body: UILabel?
    var post: PostData?
    var domain: UILabel?
    var author: UILabel?
    var selfText: UILabel?
    var numComments: UILabel?

    required init?(coder aDecoder: NSCoder) {
        fatalError("Not implemented yet")
    }

    init(withPost post: PostData, inViewController viewController: SubViewLaunchLinkManager) {
        super.init(frame: CGRectZero)

        self.post = post
        self.backgroundColor = UIColor.lightGrayColor()

        let launchLink = UIButton()
        launchLink.setImage(UIImage(named: "circle-user-7"), forState: .Normal)
        launchLink.addTarget(viewController, action: "launchLink:", forControlEvents: .TouchUpInside)
        self.addSubview(launchLink)

        selfText = UILabel()
        selfText?.backgroundColor = UIColor.whiteColor()
        selfText?.numberOfLines = 0
        selfText?.lineBreakMode = .ByWordWrapping
        selfText!.text = post.selfText
        self.addSubview(selfText!)
        selfText?.sizeToFit()

        //let attributedString = NSAttributedString(string: "Test"/*post.selfTextHtml*/, attributes: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType])
        //selfText.attributedText = attributedString

        body = UILabel()
        body!.text = post.title
        body!.numberOfLines = 0
        body!.lineBreakMode = .ByWordWrapping
        body!.textAlignment = .Justified
        self.addSubview(body!)

        domain = UILabel()
        domain!.text = post.domain
        self.addSubview(domain!)

        author = UILabel()
        author!.text = post.author
        self.addSubview(author!)

        numComments = UILabel()
        numComments!.text = "\(post.numComments)"
        self.addSubview(numComments!)

        body!.translatesAutoresizingMaskIntoConstraints = false
        domain!.translatesAutoresizingMaskIntoConstraints = false
        author!.translatesAutoresizingMaskIntoConstraints = false
        selfText!.translatesAutoresizingMaskIntoConstraints = false
        launchLink.translatesAutoresizingMaskIntoConstraints = false
        numComments!.translatesAutoresizingMaskIntoConstraints = false

        let views: [String: UIView] = ["body": body!, "domain": domain!, "author": author!, "numComments": numComments!, "launchLink": launchLink, "selfText": selfText!]
        //let selfTextSize = selfText?.sizeThatFits((selfText?.frame.size)!)
        //print(selfTextSize)
        //let metrics = ["selfTextHeight": selfTextSize!.height]

                   self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[body]-[selfText]-[domain]-|", options: [], metrics: nil, views: views))
       self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[body]-[selfText]-[author]-|", options: [], metrics: nil, views: views))
    self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[body]-[selfText]-[numComments]-|", options: [], metrics: nil, views: views))
    self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[launchLink]-[numComments]-|", options: [], metrics: nil, views: views))
    self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[body][launchLink]|", options: [], metrics: nil, views: views))
    self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[selfText][launchLink]|", options: [], metrics: nil, views: views))
    self.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[domain][author][numComments][launchLink]|", options: [], metrics: nil, views: views))
}

override func layoutSubviews() {
    super.layoutSubviews()
    body?.preferredMaxLayoutWidth = body!.bounds.width
}
}

Answer 1

从this post复制。（如果您正在寻找更多详细信息，请务必查看）

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let headerView = tableView.tableHeaderView {

        let height = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize).height
        var headerFrame = headerView.frame

        //Comparison necessary to avoid infinite loop
        if height != headerFrame.size.height {
            headerFrame.size.height = height
            headerView.frame = headerFrame
            tableView.tableHeaderView = headerView
        }
    }
}

Answer 2

使用

确定标题的帧大小

header.systemLayoutSizeFitting(UILayoutFittingCompressedSize)

当我的标题视图由单个多行标签组成时，上述答案中的

不适用于我。将标签的换行模式设置为自动换行，文本将被截断：

相反，对我有用的是使用表格视图的宽度和高度0作为目标大小：

header.systemLayoutSizeFitting(CGSize(width: tableView.bounds.width, height: 0))

将它们放在一起（我更喜欢使用扩展名）：

extension UITableView {
    func updateHeaderViewHeight() {
        if let header = self.tableHeaderView {
            let newSize = header.systemLayoutSizeFitting(CGSize(width: self.bounds.width, height: 0))
            header.frame.size.height = newSize.height
        }
    }
}

并这样称呼它：

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    tableView.updateHeaderViewHeight()
}

Answer 3

仅实现这两个UITableView委托方法对我有用：

-(CGFloat)tableView:(UITableView *)tableView estimatedHeightForHeaderInSection:(NSInteger)section
{
    return 100;
}

-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
    return UITableViewAutomaticDimension;
}

Answer 4

如果您仍然遇到上述代码示例的布局问题，则您在自定义标题视图上禁用translatesAutoresizingMaskIntoConstraints的可能性很小。在这种情况下，您需要在设置标题框后将translatesAutoresizingMaskIntoConstraints设置回true。

这是我在iOS 11上正常使用的代码示例。

public override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    guard let headerView = tableView.tableHeaderView else { return }

    let height = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height
    var headerFrame = headerView.frame

    if height != headerFrame.size.height {
        headerFrame.size.height = height
        headerView.frame = headerFrame
        tableView.tableHeaderView = headerView

        if #available(iOS 9.0, *) {
            tableView.layoutIfNeeded()
        }
    }

    headerView.translatesAutoresizingMaskIntoConstraints = true
}

Answer 5

override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        if let headerView = self.tableView.tableHeaderView {
            let headerViewFrame = headerView.frame
            let height = headerView.systemLayoutSizeFitting(headerViewFrame.size, withHorizontalFittingPriority: UILayoutPriority.defaultHigh, verticalFittingPriority: UILayoutPriority.defaultLow).height
            var headerFrame = headerView.frame
            if height != headerFrame.size.height {
                headerFrame.size.height = height
                headerView.frame = headerFrame
                self.tableView.tableHeaderView = headerView
            }
        }
    }

使用水平或垂直拟合时计算标签尺寸时出现问题

Answer 6

基于@ TravMatth和@ NSExceptional's答案：

对于动态TableView标头，具有多行文本（无论是否存在）

我的解决方法是：

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let footView = tableView.tableFooterView {
        let newSize = footView.systemLayoutSizeFitting(CGSize(width: self.view.bounds.width, height: 0))
        if newSize.height != footView.frame.size.height {
            footView.frame.size.height = newSize.height
            tableView.tableFooterView = footView
        }
    }
}

tableView.tableFooterView = footView以确保您的tableview标头或页脚已更新。并且if newSize.height != footView.frame.size.height可以帮助您避免多次调用此方法

Answer 7

**My Working Solution is:
Add this function in viewcontroller**
public override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        guard let headerView = myTableView.tableHeaderView else { return }
        let height = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height
        var headerFrame = headerView.frame

        if height != headerFrame.size.height {
            headerFrame.size.height = height
            headerView.frame = headerFrame
            myTableView.tableHeaderView = headerView

            if #available(iOS 9.0, *) {
                myTableView.layoutIfNeeded()
            }
        }

        headerView.translatesAutoresizingMaskIntoConstraints = true
} 


 **Add one line in header's view class.**
override func layoutSubviews() {
        super.layoutSubviews()
        bookingLabel.preferredMaxLayoutWidth = bookingLabel.bounds.width

    }

动态设置tableHeaderView高度

7 个答案: