Swift4 - 分页
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【中文标题】Swift4 - 分页【英文标题】：Swift4 - Pagination 【发布时间】：2018-03-27 12:04:36 【问题描述】：我是开发 ios 应用程序的新手。还是不太懂。我成功地只能从第一页很好地显示文章，但是当我向上滚动查看更多时，无法显示其他页面的其他文章。如果有人知道如何从我的收藏视图中进行分页，我真的需要帮助。下面是我使用的api的图片。
下面是我从 api 获取数据的代码 -- (Artikel.swift)
import Foundation
import Alamofire
import SwiftyJSON
import os.log
struct Artikel: ServiceCompletionHandler
static func getCategories (completionHandler: @escaping ArrayCompletionHandler)
let headers: HTTPHeaders = [
"Accept": "application/json"
]
let parameters: Parameters = [
"secret_key": Config.api_key
]
Alamofire.request("\(Config.server_address)/article-categories", method: .post, parameters: parameters, headers: headers)
.responseJSON (response) -> Void in
switch response.result
case .success:
let json = JSON(response.result.value!)
if json["data"].exists()
if let data = json["data"]["data"].array
completionHandler(data, nil)
else
completionHandler([], nil)
else
completionHandler([], nil)
case .failure(let error):
print(error)
completionHandler([], "Network error has occured.")
static func getArticles(_ category_id: Int, completionHandler: @escaping ArrayCompletionHandler)
let headers: HTTPHeaders = [
"Accept": "application/json",
"secret-key": Config.api_key]
let value: Int = category_id
let newcategory = String(describing: value)
// var nextpages = NewsSectionViewController.url
let new_api = Config.server_addforarticle + newcategory
Alamofire.request(new_api, method: .get, headers: headers)
.responseJSON (response) -> Void in
switch response.result
case .success:
let json = JSON(response.result.value!)
// dump(json, name: "testing")
if let articles = json["articles"]["data"].array
completionHandler(articles, nil)
else
completionHandler([], nil)
case .failure(let error):
print(error)
completionHandler([], "Network error has occured.")
我在这里展示我的文章。但是，是的，我不能进行分页，它只停留在 4-5 篇文章上。我只是不知道如何做我在我的 android 版本中所做的事情。
NewsSectionViewController.swift
import UIKit
import SwiftyJSON
import AlamofireImage
protocol NewsSectionViewControllerDelegate
func updateArrowPosition()
class NewsSectionViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout
// MARK: - Variables
var itemIndex: Int = 0
var category:JSON!
var stories:[JSON] = []
var delegate: NewsSectionViewControllerDelegate?
// MARK: - Views
@IBOutlet var titleLabel: UILabel!
@IBOutlet var collectionView: UICollectionView!
@IBOutlet var loadingIndicator: UIActivityIndicatorView!
// MARK: - Constraint
@IBOutlet var titleTopConstraint: NSLayoutConstraint!
override func viewDidLoad()
super.viewDidLoad()
self.titleLabel.text = category["name"].stringValue.uppercased()
self.collectionView.contentInset = UIEdgeInsetsMake(0, 0, 114, 0)
if #available(iOS 11.0, *)
if ((UIApplication.shared.keyWindow?.safeAreaInsets.top)! > CGFloat(0.0))
self.collectionView.contentInset = UIEdgeInsetsMake(0, 0, 173, 0)
self.collectionView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 173, 0)
self.loadingIndicator.startAnimating()
Artikel.getArticles(category["id"].intValue)
(articles, error) in
self.loadingIndicator.stopAnimating()
if error == nil
self.stories = articles
self.collectionView.reloadData()
override func didReceiveMemoryWarning()
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
// MARK: - Collection View
func numberOfSections(in collectionView: UICollectionView) -> Int
return 1
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
return self.stories.count - 1
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
var cell: NewsItemCollectionViewCell?
let item = stories[indexPath.row + 1]
if indexPath.row == 0
cell = collectionView.dequeueReusableCell(withReuseIdentifier: "BigCell", for: indexPath) as? NewsItemCollectionViewCell
else
cell = collectionView.dequeueReusableCell(withReuseIdentifier: "SmallCell", for: indexPath) as? NewsItemCollectionViewCell
cell!.titleLabel.text = item["title"].stringValue
if let thumbUrlString = item["banner_url_large"].string
if let thumbUrl = URL(string: thumbUrlString)
cell?.coverImageView.af_setImage(withURL: thumbUrl)
let wpDateFormatter = DateFormatter()
wpDateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
let dayDateFormatter = DateFormatter()
dayDateFormatter.dateStyle = .medium
dayDateFormatter.doesRelativeDateFormatting = true
let date = wpDateFormatter.date(from: item["date_publish_web"].stringValue)!
cell!.timestampLabel.text = dayDateFormatter.string(from: date)
return cell!
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
let story = self.stories[indexPath.row + 1]
let newsContents = self.storyboard?.instantiateViewController(withIdentifier: "NewsContent") as! NewsContentViewController
newsContents.story = story
newsContents.title = self.category["name"].string
self.navigationController?.pushViewController(newsContents, animated: true)
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
if indexPath.row == 0
let width = UIScreen.main.bounds.width - 30
return CGSize(width: width, height: 385 - 20)
else
let width = (UIScreen.main.bounds.width - 45) / 2
return CGSize(width: width, height: 210)
// MARK: - ScrollView
func scrollViewDidScroll(_ scrollView: UIScrollView)
if scrollView == self.collectionView
self.titleTopConstraint.constant = 30 - scrollView.contentOffset.y
if let delegate = self.delegate
delegate.updateArrowPosition()
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
*/
任何帮助我都非常感谢并提前感谢您:)
【问题讨论】：
谢谢@Kuldeep ...会尝试但是..你知道如何从我的api实现分页吗？请您至少显示我的代码中的提示编辑。对不起，我只是很新:( 【参考方案1】：在 NewsSectionViewController 中：
1) 添加全局变量：
a) var nextPageUrl: String? ;
b) let numberOfPagination = 5 (5 它是一个 url 页面中的多个项目);
c) 添加变量hasMoreItems
var hasMoreItems: Bool
get
guard let count = nextPageUrl?.count, count > 0 else
return false
return true
d) 添加变量numberOfItems
var numberOfItems: Int
get
return secrets.count
2) 将此行 self.stories = articles 更改为 self.stories += articles
3) 添加分页功能：
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath)
if (indexPath.item + 1 == numberOfItems) && ((indexPath.item + 1) % numberOfPagination == 0)
if self.presenter.hasMoreItems
self.loadData()
f) 添加func loadData()
func loadData()
Artikel.getArticles(category["id"].intValue, nextPageUrl: nextPageUrl)
(articles, error) in
self.loadingIndicator.stopAnimating()
if error == nil
self.stories = articles
self.collectionView.reloadData()
在 Artikel 中：
1) 改变getArticles函数
static func getArticles(_ category_id: Int, nextPageUrl: String?, completionHandler: @escaping ArrayCompletionHandler)
//...
let new_api = nextPageUrl ?? Config.server_addforarticle + newcategory
//...
2) 在此函数中，您可以在ArrayCompletionHandler 中返回nextPageUrl 值
【讨论】：
谢谢你的朋友.. 你的指南对像我这样的菜鸟很有帮助.... :) 再次感谢以上是关于Swift4 - 分页的主要内容，如果未能解决你的问题，请参考以下文章