swift – 实现collectionViewCell高度自适应

实现思路：  

1）设置layout的estimatedItemSize属性

flowLayout.estimatedItemSize = CGSize(width: UIScreen.main.bounds.width, height: 50)

2）为cell内部的view控件添加上下约束，保证竖直高度被撑满

3）重写preferredLayoutAttributesFitting方法，重新计算cell的高度

override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
    self.setNeedsLayout()
    self.layoutIfNeeded()

    // 重新计算contentView的高度
    let size = self.contentView.systemLayoutSizeFitting(layoutAttributes.size)
    var cellFrame = layoutAttributes.frame
    cellFrame.size.height = size.height
    layoutAttributes.frame = cellFrame
        
    return layoutAttributes
}

务必注意：要把cell内部的view添加到cell的self.contentView上才能高度自适应，直接添加到self上不行！！！

实现效果：

​​​​​​​​​​​​​​

​​​​​​​demo如下：

1、创建CollectionViewNormalCell.swift文件，代码如下：

 import UIKit
import SnapKit

class CollectionViewNormalCell: UICollectionViewCell {
    public var model: (String, String)? {
        didSet {
            guard let model = self.model else {
                return
            }
            
            self.titleLabel.text = model.0
            self.subTitlLabel.text = model.1
        }
    }
    
    private var titleLabel: UILabel = UILabel()
    private var subTitlLabel: UILabel = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.setupUI()
    }
    
    override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
        self.setNeedsLayout()
        self.layoutIfNeeded()

        // 重新计算contentView的高度
        let size = self.contentView.systemLayoutSizeFitting(layoutAttributes.size)
        var cellFrame = layoutAttributes.frame
        cellFrame.size.height = size.height
        layoutAttributes.frame = cellFrame
        
        return layoutAttributes
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setupUI() {
        self.backgroundColor = .white
        
        self.contentView.addSubview(self.titleLabel)
        self.titleLabel.snp.makeConstraints{ make in
            make.left.equalToSuperview().offset(15)
            make.centerY.equalToSuperview()
            make.width.equalTo(50)
        }
        self.titleLabel.textColor = .black
        self.titleLabel.font = .systemFont(ofSize: 17, weight: .medium)
        self.titleLabel.numberOfLines = 1
        
        self.contentView.addSubview(self.subTitlLabel)
        self.subTitlLabel.snp.makeConstraints { make in
            make.left.equalTo(self.titleLabel.snp.right).offset(15)
            make.right.equalToSuperview().offset(-15)
            make.top.equalToSuperview().offset(15)
            make.bottom.equalToSuperview().offset(-15)
        }
        self.subTitlLabel.numberOfLines = 0
        self.subTitlLabel.textAlignment = .justified
        self.subTitlLabel.textColor = .darkGray
        self.subTitlLabel.font = .systemFont(ofSize: 13)
    }
}

2、创建CollectionViewNormalViewController.swift文件，代码如下

import UIKit
import SnapKit

class CollectionViewNormalViewController: UIViewController {
    // MARK: - 定义collectionView
    public lazy var collectionView: UICollectionView = { [weak self] in
        // 设置collectionView的布局
        let flowLayout = UICollectionViewFlowLayout()
        flowLayout.scrollDirection = .vertical
        flowLayout.minimumLineSpacing = 0
        flowLayout.minimumInteritemSpacing = 0
        flowLayout.sectionInset = UIEdgeInsets(top: 10, left: 0, bottom: 0, right: 0)
        // 这里定义flowLayout的预估大小
        flowLayout.estimatedItemSize = CGSize(width: UIScreen.main.bounds.width, height: 50)
        
        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: flowLayout)
        collectionView.autoresizingMask = [.flexibleHeight]
        collectionView.showsVerticalScrollIndicator = false
        collectionView.delegate = self
        collectionView.dataSource = self
        
        collectionView.register(CollectionViewNormalCell.self, forCellWithReuseIdentifier: "CollectionViewNormalCell")
        
        return collectionView
    }()
    
    // MARK: - 模拟数据
    public var list: [(String, String)] = [
        ("标题1", "介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字"),
        ("标题2", "介绍文字介绍文字介绍文字介绍文字"),
        ("标题3",  "介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字介绍文字")
    ]
    
    // MARK: - setup UI
    override func viewDidLoad() {
        super.viewDidLoad()
        self.setupUI()
    }
    
    func setupUI() {
        self.title = "collectionView高度自适应"
        self.collectionView.backgroundColor = UIColor(red: 248/155.0, green: 248/255.0, blue: 248/255.0, alpha: 1.0)
        
        // 添加collectionView
        self.view.addSubview(self.collectionView)
        self.collectionView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
    }
}

// MARK: - 实现CollectionView的代理和数据源
extension CollectionViewNormalViewController: UICollectionViewDelegate, UICollectionViewDataSource {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return self.list.count
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewNormalCell", for: indexPath) as! CollectionViewNormalCell
        cell.model = self.list[indexPath.section]
        return cell
    }
    
}

代码007普通

打赏 收藏 海报 链接