获取自定义单元格中标签的高度以用于主视图控制器中的 heightForRowAt [英] getting the height of a label in custom cell to use for heightForRowAt in my main view controller

问题描述

我有一个视图控制器，它使用一个名为 searchCell 的自定义单元格来引入内容，我想知道如何获取标签 lblLeft 的高度并在 tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) 中使用它-> CGFloat 函数返回标签的高度.我在主视图控制器中使用的代码:

I have a view controller that uses a custom cell called searchCell to bring content in and I am wondering how I can get the height of the label lblLeft and use it in the tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat function to return the height of the label. The code I'm using in my Main View Controller:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: 
    IndexPath) -> UITableViewCell {
    if searchMode == searching {
        let cell: MHSearchCell = tableView.dequeueReusableCell(withIdentifier: 
        MHSearchCell.ReusableIdentifier()) as! MHSearchCell

        cell.helper = helpers[indexPath.row]
        cell.delegate = self

        return cell
  }
}

在我的 MHSearchCell 中创建标签的部分代码，标签在这里作为 IBOutlet 连接:

Part of the code that creates the label in my MHSearchCell, the label is connected here as an IBOutlet:

lblLeft.text = ""

        if let expertiseCount = helper.expertise {

            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.lineSpacing = 5
            paragraphStyle.lineBreakMode = .byWordWrapping
            paragraphStyle.alignment = NSTextAlignment.center
            lblLeft.numberOfLines = 0

            let finalString = expertiseCount.map({$0.name!}).joined(separator: "   \u{00B7}   ")
            let finalAttributedString = NSMutableAttributedString(string: finalString, attributes: [NSParagraphStyleAttributeName:paragraphStyle])
            lblLeft.attributedText = finalAttributedString
        }

推荐答案

第一种方法要么使用自动尺寸标注

1) 对标签应用适当的约束检查下图.

1) Apply Appropriate constraints on label check the image below.

确保故事板中的标签 Lines 设置为 0.

Make sure label Lines are set to 0 in storyboard.

现在在控制器类中执行此操作-:

Now in controller class do this-:

//MArk-: ViewDidLoad
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        yourTableView.estimatedRowHeight = 142.0 // Default cell height from storyboard

        yourTableView.rowHeight = UITableViewAutomaticDimension
    }

表格功能-:

 public func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat{
 return UITableViewAutomaticDimension
    }

另一种计算estimatedHeightForLabel-的方法:

1) 对标签应用与上述相同的约束

1) Apply same constraints to label as mentioned above

2) 使用 NSString 的 boundingRect 方法从标签中找到单元格的准确高度 -:

2) use boundingRect method of NSString to find exact height for cell from label -:

表格视图功能-:

extension ViewController : UITableViewDelegate,UITableViewDataSource{
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
        return value.count
    }


    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as? testingCell
        cell?.textlabel.text = value[indexPath.row]
        return cell!
    }

    // Number of sections in table

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }// Default is 1 if not implemented

    public func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat{
        let text = value[indexPath.row]
        let estimatedheight = calculateEstimatedHeight(text: text)
        return estimatedheight.height
    }

    func calculateEstimatedHeight(text:String) -> CGRect{
        let size = CGSize(width: view.frame.width, height: 1000)
        let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
        let attribute = [NSFontAttributeName:UIFont.systemFont(ofSize: 17)]
        let estimatedHeight = NSString(string: text).boundingRect(with: size, options: options, attributes: attribute, context: nil)
        return estimatedHeight
    }

记住-:

1) 提供与标签相同的字体大小.

1) Provide same font size you have for label.

2) 对于多行标签使用选项为 .usesLineFragmentOrigin.

2) For multiline label use option as .usesLineFragmentOrigin.

CustomCellClass-:

import UIKit

class testingCell: UITableViewCell {

    @IBOutlet weak var textlabel: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}

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