选择collectionView单元格时如何获取项目ID

问题描述

我只想在选择 collectionView 的项目时将项目 id 传递给下一个视图控制器。

这里存储我从 API 获取的数据

这是一些代码 -->

var posts = [[String: Any]]()
func apicall() {
        let Url = String(format: "http:example.com")
        guard let serviceUrl = URL(string: Url) else { return }
        
        var request = URLRequest(url: serviceUrl)
        request.httpMethod = "POST"
        request.setValue("Application/json",forHTTPHeaderField: "Content-Type")
        
        
        let session = URLSession.shared
        session.dataTask(with: request) { (data,response,error) in
            if let response = response {
                print(response)
            }
            if let data = data {
                do {
                    if let json = try JSONSerialization.jsonObject(with: data,options: []) as? [String : Any]{
                        
                        self.posts = (json["data"] as? [[String : Any]])!
                        
                        dispatchQueue.main.async() {
                            self.collectionView.reloadData()
                        }
                    }
                } catch {
                    print(error)
                }
            }
            }.resume()
    }

现在我得到了数据，我想传递只被选中的那个项目的项目 id

 @IBAction func onClickNext(_ sender: Any) {
        let controller = self.storyboard?.instantiateViewController(withIdentifier: "secondViewController") as! secondViewController
        self.navigationController?.pushViewController(controller,animated: true)
       
    }

这里是 didSelectItemAt 索引路径的代码

func collectionView(_ collectionView: UICollectionView,didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! secondCollectionViewCell
}

解决方法

始终从模型（数据源数组）中获取数据，而不是从视图

func collectionView(_ collectionView: UICollectionView,didSelectItemAt indexPath: IndexPath) {
        let item = self.posts[indexPath.item]
        let id = item["id"]
        // do things with id
}

,

那一刻，如果您启用了选择，集合视图将能够返回集合视图中所有选定单元格的 IndexPath。 请在 UICollectionView

上查看此属性

var indexPathsForSelectedItems: [IndexPath]? { get }

apple documentation for indexPathForSelectedItems

然后在您的 @IBAction func 处执行此操作

@IBAction func onClickNext(_ sender: Any) {
  // logic to grab the id from self.posts using the selected indexPaths ie.
  let selectedItems = self.collectionView.indexPathsForSelectedItems ?? []
  let ids = selectedItems.compactMap { self.posts[$0.row] }

  let controller = self.storyboard?.instantiateViewController(withIdentifier: 
           "secondViewController") as! secondViewController
  controller.selectedIds = ids // all the selected ids
  
  self.navigationController?.pushViewController(controller,animated: true)
}

所以你应该做类似的事情，我不知道你的 self.posts 属性中的数据结构是什么样的，但上面的代码给了你一个想法。为了简化这一过程，请尝试在操场中运行以下代码并查看结果。

import UIKit

let posts: [String] = ["Carrot_Post","Pencil_Post","Dish_Post","Data_Post","iOS_Post","Kitties_Post","VideoGamesPost","Bitcoin_Post"]
let selected: [Int] = [1,3,5]

let items: [String] = selected.compactMap({ posts[$0] })

print(items) // output: ["Pencil_Post","Carrot_Post","Kitties_Post"]

希望对您的问题有所帮助。