点击按钮时如何使collectionView标头隐藏？

Posted 2023-03-14

【中文标题】点击按钮时如何使collectionView标头隐藏？

【英文标题】：How can I make a collectionView header become hidden when a button is tapped?

【发布时间】：2018-07-10 02:20:02

【问题描述】：

我试图在点击按钮时隐藏 collectionView 标头，但我似乎无法从 IBAction 函数内部访问此属性。

按钮功能

    var buttonPressed:Bool = true
    @IBAction func changeView(_ sender: Any) 
        if buttonPressed
        UIView.animate(withDuration: 0.05)

            self.buttonPressed = !self.buttonPressed
            print("Ive been expanded")
        
        
        else
            UIView.animate(withDuration: 0.05)
                self.buttonPressed = !self.buttonPressed
            
        
       

完整的代码

import UIKit

class ViewController: UIViewController,UICollectionViewDataSource,UICollectionViewDelegate 

    @IBOutlet weak var animateCollectionView: UICollectionView!



    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        animateCollectionView.dataSource = self
        animateCollectionView.delegate = self
        animateCollectionView.backgroundColor = UIColor.blue
        animateCollectionView.frame = CGRect(x: 0, y: 100, width: 600, height: 1000)
        let layout = animateCollectionView.collectionViewLayout as? UICollectionViewFlowLayout
        layout?.sectionHeadersPinToVisibleBounds = true
         self.view.sendSubview(toBack: self.animateCollectionView)
    

    override func didReceiveMemoryWarning() 
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    


    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int 

        return 200
    

    func numberOfSections(in collectionView: UICollectionView) -> Int 
        return 1
    

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell 
        let cell = self.animateCollectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! customCell
        cell.cellLabel.text = "\(indexPath.item)"
        cell.backgroundColor = UIColor.orange
        return cell


    

    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView 
        // returning the search bar for header
        let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "headerCell", for: indexPath) as! customHeader

        header.backgroundColor = UIColor.purple

        return header
    

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize 
        // if section is above search bar we need to make its height 0
        if section == 0 
            return CGSize(width: 0, height: 0)
        
        // for section header i.e. actual search bar
        return CGSize(width: animateCollectionView.frame.width, height: 50)
    


    var buttonPressed:Bool = true
    @IBAction func changeView(_ sender: Any) 
        if buttonPressed
        UIView.animate(withDuration: 0.05)
      self.buttonPressed = !self.buttonPressed
            print("Ive been expanded")
        
        
        else
            UIView.animate(withDuration: 0.05)

            
        
    






class customCell :UICollectionViewCell
    @IBOutlet weak var cellLabel: UILabel!


class customHeader: UICollectionReusableView

【问题讨论】：

只返回零标头高度

【参考方案1】：

正如@SPatel 提到的，将大小设置为零。

然后设置从单元到 VC 的委托方法，以便 VC 知道使布局无效。

例如：

细胞类

protocol HideHeaderViewDelegate 
    func hideHeaderView(hide: Bool)


class HeaderView: UICollectionReusableView 

    var delegate: HideHeaderViewDelegate?

    @IBOutlet weak var hideButton: UIButton!

    override func awakeFromNib() 
        super.awakeFromNib()
    

    @IBAction func hideButtonAction(_ sender: Any) 
        self.frame.size = CGSize.zero
        guard let delegate = delegate else  return 
        delegate.hideHeaderView(hide: true)
    

视图控制器

extension ViewController: HideHeaderView 
    func hideHeaderView(hide: Bool) 
        if hide == true 
            print(hide)
            // invalidate your layout here
        
    

别忘了设置委托

func collectionView(_ collectionView: UICollectionView,
                        viewForSupplementaryElementOfKind kind: String,
                        at indexPath: IndexPath) -> UICollectionReusableView 
        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader,
                                                                         withReuseIdentifier: "headerView", for: indexPath) as! HeaderView
        headerView.delegate = self

    return headerView
    

【讨论】：

非常感谢您的回复，非常有帮助。我很好奇我是否想通过 viewController 中发生的事件触发标题隐藏让我们说通过 viewController 中的按钮或 collectionView 滚动这可能吗？您将如何设置委托？

@TheRedCamaro3.03.0 UICollectionView 是 ScrollView 的子类。你需要这个委托：UIScrollViewDelegate，然后你可以使用它的方法。有关这方面的更多信息，我会搜索 SOF 或发布一个单独的问题。 :)