集合视图自动调整大小和设置重复背景

Posted 2023-03-14

【中文标题】集合视图自动调整大小和设置重复背景

【英文标题】：Collection view auto resizing and setup repeating background

【发布时间】：2020-02-06 07:12:42

【问题描述】：

我正在使用集合视图从 API 加载数据。在这里，我想扩展集合视图高度的大小，而不是在集合视图内滚动。并且还需要根据collection view高度重复背景图片。 这是android布局，我想开发类似的。Tap here

导入 UIKit 进口核弹 导入 SVProgressHUD 导入 JSONJoy 类 HomeViewController: UIViewController

@IBOutlet weak var categoryCollection: UICollectionView!
@IBOutlet weak var tabbar: UITabBar!



var sectors:[Sector] = []
var timer = Timer()
var counter = 0
var selectedSector = ""
var selectedSectorName = ""
var webService = ApiService()
let plist = PlistHelper()
override func viewDidLoad() 
    super.viewDidLoad()

    self.categoryCollection.dataSource = self
    self.categoryCollection.delegate = self
    for item in tabbar.items ?? []
        item.image = item.image?.withRenderingMode(.alwaysOriginal)

    
    UITabBarItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.white], for: .normal)
    UITabBarItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.black], for: .selected)
        listSectors()

    self.categoryCollection.backgroundColor = UIColor(patternImage: UIImage(named: "bg")!)


override func viewWillAppear(_ animated: Bool) 
    listbanners()


override func viewWillDisappear(_ animated: Bool) 
    self.timer.invalidate()

override func prepare(for segue: UIStoryboardSegue, sender: Any?) 
    if(segue.identifier == "sectors")
        let vc  = segue.destination as! SectorsViewController
        vc.sectorCode = selectedSector
        vc.sectorName = selectedSectorName
    




func listSectors()

    webService.listSectors( (sectors, message, status) in

        if(status)
            if let resData = sectors.arrayObject 
                do
                    for data in resData
                        self.sectors.append(try Sector(JSONLoader(data)))

                    

                    DispatchQueue.main.async 
                        self.categoryCollection.reloadData()

                    

                
                catch let error 
                    print("JSonJoyError:\(error)")
                
            
        
    )

扩展 HomeViewController: UICollectionViewDelegate, UICollectionViewDataSource

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int 
    if(collectionView == bannerCollection)
        return banners.count
    
    else 
        return sectors.count
    



func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell 
    let options = ImageLoadingOptions(placeholder: UIImage(named: "bannerPlaceholder"),transition: .fadeIn(duration: 0.33))
    if(collectionView == bannerCollection)
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! DataCollectionViewCell


    Nuke.loadImage(with: URL(string: banners[indexPath.row].ImageUrl ?? "")!, options: options, into:cell.img)

    return cell
    
    else

            let cell = categoryCollection.dequeueReusableCell(withReuseIdentifier: "catCell", for: indexPath) as! catogeryCollectionViewCell
            Nuke.loadImage(with: URL(string: sectors[indexPath.row].ImageUrl ?? "")!, options: options, into:cell.photoImageView)


                return cell
    

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) 
    if(collectionView == categoryCollection)
        selectedSector = sectors[indexPath.row].Code ?? "FOOD"
        selectedSectorName = sectors[indexPath.row].Name ?? "FOOD"
        self.performSegue(withIdentifier: "sectors", sender: self)
    

扩展 HomeViewController: UICollectionViewDelegateFlowLayout

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets 
    return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)


func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize 
    if(collectionView == bannerCollection)
    let size = bannerCollection.frame.size

        return CGSize(width: size.width, height: size.height - 10)
    
    else
        let size = categoryCollection.frame.size
          print("size\(size)")
        return CGSize(width: (size.width / 2) - 8, height:120)
    


func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat 
    return 30


func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat 
    return 0.0

【问题讨论】：

请详细、恰当地询问。

请添加一些代码和细节。谢谢

对不起.. 我添加了代码。我想在添加新扇区时扩展集合视图的高度。

@neeraj joshi 的回答是对的，我认为你可以试试。

【参考方案1】：

以下步骤可以帮助您根据数据增加您的收藏视图高度。

创建高度约束出口。

在主线程中以 0.2 秒的延迟在集合视图中加载数据后， 设置高度约束常量 = 集合视图内容大小高度。

【讨论】：

谢谢。但我得到一个错误。 “无法将类型 'CGSize' 的值分配给类型 'CGFloat'”

重载collectionview后试试这个 请分开行@HaifaMunafar CGFloat height = myCollectionView.collectionViewLayout.collectionViewContentSize.height heightConstraint.constant = height self.view.setNeedsLayout() 或 self.view.layoutIfNeeded()跨度>

@HaifaMunafar 内容大小的高度是 CGFloat 本身。