Merge pull request #2 from loloop/mc/on-appear

0.0.2 release

Author: loloop

Examples/HackerNews/HackerNews.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		B40EFB752B36244600DE023E /* Identifiable+RemoveDuplicates.swift in Sources */ = {isa = PBXBuildFile; fileRef = B40EFB742B36244600DE023E /* Identifiable+RemoveDuplicates.swift */; };
 		B44C4EE22B2CC1D000711A81 /* HackerNewsApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = B44C4EE12B2CC1D000711A81 /* HackerNewsApp.swift */; };
 		B44C4EE42B2CC1D000711A81 /* HackerNewsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B44C4EE32B2CC1D000711A81 /* HackerNewsViewController.swift */; };
 		B44C4EE62B2CC1D100711A81 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = B44C4EE52B2CC1D100711A81 /* Assets.xcassets */; };
@@ -16,6 +17,7 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		B40EFB742B36244600DE023E /* Identifiable+RemoveDuplicates.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Identifiable+RemoveDuplicates.swift"; sourceTree = "<group>"; };
 		B44C4EDE2B2CC1D000711A81 /* HackerNews.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = HackerNews.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		B44C4EE12B2CC1D000711A81 /* HackerNewsApp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HackerNewsApp.swift; sourceTree = "<group>"; };
 		B44C4EE32B2CC1D000711A81 /* HackerNewsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HackerNewsViewController.swift; sourceTree = "<group>"; };
@@ -61,6 +63,7 @@
 				B44C4EE12B2CC1D000711A81 /* HackerNewsApp.swift */,
 				B44C4EE32B2CC1D000711A81 /* HackerNewsViewController.swift */,
 				B44C4EF32B2CD8F700711A81 /* News.swift */,
+				B40EFB742B36244600DE023E /* Identifiable+RemoveDuplicates.swift */,
 				B44C4EE52B2CC1D100711A81 /* Assets.xcassets */,
 				B44C4EE72B2CC1D100711A81 /* Preview Content */,
 			);
@@ -129,6 +132,8 @@
 				Base,
 			);
 			mainGroup = B44C4ED52B2CC1D000711A81;
+			packageReferences = (
+			);
 			productRefGroup = B44C4EDF2B2CC1D000711A81 /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
@@ -156,6 +161,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				B44C4EE42B2CC1D000711A81 /* HackerNewsViewController.swift in Sources */,
+				B40EFB752B36244600DE023E /* Identifiable+RemoveDuplicates.swift in Sources */,
 				B44C4EF42B2CD8F700711A81 /* News.swift in Sources */,
 				B44C4EE22B2CC1D000711A81 /* HackerNewsApp.swift in Sources */,
 			);
@@ -300,7 +306,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 17.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -331,7 +337,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 17.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

Examples/HackerNews/HackerNews/HackerNewsApp.swift

@@ -19,8 +19,3 @@ struct HackerNewsApp: App {
     }
   }
 }
-
-struct HackerNews: UIViewControllerRepresentable {
-  func makeUIViewController(context: Context) -> HackerNewsViewController { .init() }
-  func updateUIViewController(_ uiViewController: HackerNewsViewController, context: Context) {}
-}

Examples/HackerNews/HackerNews/HackerNewsViewController.swift

@@ -16,24 +16,37 @@ enum APIState<T> {
   case finished(T)
 }
 
+struct Page<T: Hashable> {
+  let items: [T]
+  let currentPage: Int
+}
+
 final class HackerNewsViewController: DiffableViewController {
 
   override func viewDidLoad() {
     super.viewDidLoad()
-
-    reload()
+    configureCollectionView()
 
     Task {
-      try await fetchNews()
+      state = .loading
+      await reload()
+      try await fetch()
     }
   }
 
-  var state: APIState<[NewsItem]> = .idle {
-    didSet {
-      reload()
-    }
+  func configureCollectionView() {
+    collectionView.refreshControl = UIRefreshControl(
+      frame: .zero,
+      primaryAction: .init(
+        handler: { [weak self] _ in
+          Task {
+            try await self?.fetch(fullyReload: true)
+          }
+        }))
   }
 
+  var state: APIState<Page<NewsItem>> = .idle
+
   @CollectionViewBuilder
   override var sections: [any CollectionSection] {
     List {
@@ -43,7 +56,7 @@ final class HackerNewsViewController: DiffableViewController {
       case .loading:
         ActivityIndicator()
       case .finished(let news):
-        ForEach(data: news) { item in
+        ForEach(data: news.items) { item in
           News(item)
             .onTap { [weak self] in
               guard let url = URL(string: item.url) else { return }
@@ -52,25 +65,57 @@ final class HackerNewsViewController: DiffableViewController {
                 .navigationController?
                 .present(controller, animated: true)
             }
-             .padding(.vertical(8).horizontal(12))
+            .padding(.vertical(8).horizontal(12))
+        }
+        if news.currentPage < 10 {
+          ActivityIndicator()
+            .onAppear { [weak self] in
+              try await self?.fetch()
+            }
         }
       }
     }
     .contentInsetsReference(.readableContent)
   }
 
-  func fetchNews() async throws {
-    state = .loading
+  func fetch(fullyReload: Bool = false) async throws {
+    let currentPage = if case .finished(let page) = state, !fullyReload {
+      page.currentPage
+    } else {
+      1
+    }
 
-    guard let url = URL(string: "https://api.hackerwebapp.com/news") else { return }
+    guard let url = URL(
+      string: "https://api.hackerwebapp.com/news?page=\(currentPage)")
+    else { return }
+    
     let (data, _) = try await URLSession.shared.data(from: url)
     let decoder = JSONDecoder()
     decoder.keyDecodingStrategy = .convertFromSnakeCase
     let news = try decoder.decode([NewsItem].self, from: data)
-    state = .finished(news)
+
+    if case .finished(let t) = state {
+      state = .finished(
+        .init(
+          items: (t.items + news).removeDuplicates(),
+          currentPage: currentPage+1))
+    } else {
+      state = .finished(
+        .init(
+          items: news,
+          currentPage: currentPage+1))
+    }
+
+    collectionView.refreshControl?.endRefreshing()
+    await reload()
   }
 }
 
+struct HackerNews: UIViewControllerRepresentable {
+  func makeUIViewController(context: Context) -> HackerNewsViewController { .init() }
+  func updateUIViewController(_ uiViewController: HackerNewsViewController, context: Context) {}
+}
+
 #Preview {
   NavigationStack {
     HackerNews()

Examples/HackerNews/HackerNews/Identifiable+RemoveDuplicates.swift

@@ -0,0 +1,21 @@
+//
+//  Identifiable+RemoveDuplicates.swift
+//  HackerNews
+//
+//  Created by Mauricio Cardozo on 22/12/23.
+//
+
+import Foundation
+
+extension Array where Element: Identifiable {
+  func removeDuplicates() -> Self {
+    var uniqueElements: [Element] = []
+    for element in self {
+      if !uniqueElements.contains(where: { $0.id == element.id }) {
+        uniqueElements.append(element)
+      }
+    }
+
+    return uniqueElements
+  }
+}

Examples/HackerNews/HackerNews/News.swift

@@ -9,15 +9,15 @@ import DiffableUI
 import Foundation
 import SwiftUI
 
-struct NewsItem: Codable, Hashable {
+struct NewsItem: Codable, Hashable, Identifiable {
   let id: Int
   let title: String
   let points: Int?
   let user: String?
   let timeAgo: String
   let commentsCount: Int
   let url: String
-  let domain: String
+  let domain: String?
 }
 
 struct News: CollectionItem {
@@ -30,7 +30,7 @@ struct News: CollectionItem {
   var reuseIdentifier: String { "news-cell" }
   func configure(cell: NewsCell) {
     cell.title = item.title
-    cell.domain = "(\(item.domain))"
+    cell.domain = "(\(item.domain ?? ""))"
     cell.username = if let user = item.user {
       "by \(user)"
     } else { "" }

Sources/DiffableUI/CollectionItem.swift

@@ -19,6 +19,7 @@ public protocol CollectionItem: Equatable, Hashable, Identifiable {
   func configure(cell: CellType)
   func didSelect()
   func setBehaviors(cell: CellType)
+  func willDisplay()
 }
 
 // MARK: - Internal behavbiors & default conformances
@@ -29,6 +30,8 @@ extension CollectionItem {
 
   public func setBehaviors(cell: CellType) {}
 
+  public func willDisplay() {}
+
   public var cellClass: CellType.Type {
     CellType.self
   }

Sources/DiffableUI/DiffableViewController.swift

@@ -42,6 +42,25 @@ open class DiffableViewController: UICollectionViewController {
     let oldValue = self.computedSections
     self.computedSections = sections
 
+    updateAllVisibleItems(
+      oldSections: oldValue,
+      newSections: sections,
+      collectionView: collectionView,
+      dataSource: diffableDataSource)
+
+    let shouldAnimate = animated && !oldValue.isEmpty && !computedSections.isEmpty
+
+      diffableDataSource.apply(
+        computedSections.snapshot,
+        animatingDifferences: shouldAnimate,
+        completion: completion)
+  }
+
+  @MainActor
+  public func reload(animated: Bool = true, completion: (() -> Void)? = nil) async {
+    let oldValue = self.computedSections
+    self.computedSections = sections
+
     updateAllVisibleItems(
       oldSections: oldValue,
       newSections: sections,
@@ -111,6 +130,15 @@ open class DiffableViewController: UICollectionViewController {
     item.didSelect()
   }
 
+  public override func collectionView(
+    _ collectionView: UICollectionView,
+    willDisplay cell: UICollectionViewCell,
+    forItemAt indexPath: IndexPath)
+  {
+    let item = computedSections[indexPath.section].items[indexPath.row]
+    item.willDisplay()
+  }
+
   private static func cellProvider(
     collectionView: UICollectionView,
     indexPath: IndexPath,

Sources/DiffableUI/Items/ForEach.swift

@@ -15,7 +15,7 @@ extension CollectionItemBuilder {
 }
 
 public struct ForEach {
-  public init<T>(data: [T], @CollectionItemBuilder items: (T) -> [any CollectionItem]) {
+  public init<T>(data: any RandomAccessCollection<T>, @CollectionItemBuilder items: (T) -> [any CollectionItem]) {
     self.items = data.map { items($0) }.flatMap { $0 }
   }
 

Sources/DiffableUI/Items/Tappable.swift

@@ -29,6 +29,7 @@ public struct Tappable<T: CollectionItem>: CollectionItem {
   }
 
   public func didSelect() {
+    _innerItem.didSelect()
     _action?()
   }
 

Sources/DiffableUI/Items/Taskable.swift

@@ -0,0 +1,65 @@
+//
+//  OnAppearable.swift
+//
+//
+//  Created by Mauricio Cardozo on 21/12/23.
+//
+
+#if canImport(UIKit)
+import Foundation
+
+public struct Taskable<T: CollectionItem>: CollectionItem {
+  init(
+    item: T,
+    priority: TaskPriority?,
+    action: @escaping () async throws -> Void) {
+    self._innerItem = item
+    self.priority = priority
+    self.action = action
+  }
+
+  let _innerItem: T
+  let priority: TaskPriority?
+  let action: (() async throws -> Void)?
+
+  public var id: AnyHashable {
+    _innerItem.id
+  }
+
+  public var reuseIdentifier: String {
+    _innerItem.reuseIdentifier + "-taskable"
+  }
+
+  public var item: some Hashable {
+    _innerItem.item
+  }
+
+  public func didSelect() {
+    _innerItem.didSelect()
+  }
+
+  public func setBehaviors(cell: T.CellType) {
+    _innerItem.setBehaviors(cell: cell)
+  }
+
+  public func configure(cell: T.CellType) {
+    _innerItem.configure(cell: cell)
+  }
+
+  public func willDisplay() {
+    _innerItem.willDisplay()
+    Task(priority: priority) {
+      try await action?()
+    }
+  }
+}
+
+extension CollectionItem {
+  public func onAppear(
+    priority: TaskPriority? = nil,
+    action: @escaping () async throws -> Void) -> some CollectionItem
+  {
+    Taskable(item: self, priority: priority, action: action)
+  }
+}
+#endif