Automatically load the next page when the user reaches the end

avery-pierce · Feb 20, 2021 · 2bc34f6 · 2bc34f6
1 parent 5039f3d
commit 2bc34f6
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Showing 2 changed files with 34 additions and 9 deletions.
diff --git a/Cavy/Views/Screens/Listing/EndlessPostListView.swift b/Cavy/Views/Screens/Listing/EndlessPostListView.swift
@@ -48,7 +48,7 @@ struct EndlessPostListView: View {
     }
 
     var body: some View {
-        ListingView(postLoader.posts)
+        ListingView(postLoader.posts, isNextPageLoading: postLoader.nextPageLoading, onLoadNextPage: { postLoader.loadNextPage() })
             .onAppear(perform: {
                 postLoader.loadFirstPage()
             })
@@ -90,25 +90,34 @@ class EndlessPostLoader: ObservableObject {
     })
 
     @Published var posts: [CavyPost] = []
+    @Published var nextPageLoading: Bool = false
 
     private var cancelBag = Set<AnyCancellable>()
 
     init(_ intent: ListingIntent) {
         self.intent = intent
 
         loadedPosts
-            .breakpoint()
-            .sink { (posts) in
-                self.posts = posts
-            }.store(in: &cancelBag)
+            .assign(to: \.posts, on: self)
+            .store(in: &cancelBag)
+
+        isNextPageLoading
+            .assign(to: \.nextPageLoading, on: self)
+            .store(in: &cancelBag)
     }
 
     func loadNextPage() {
-        let nextResource = intent.createResource(pageNumber: nextPageNumber)
+        let nextResource = intent.createResource(limit: 50, pageNumber: nextPageNumber)
         pages.append(nextResource)
         nextResource.load()
     }
 
+    func loadNextPageIfNeeded() {
+        if !nextPageLoading {
+            loadNextPage()
+        }
+    }
+
     func loadFirstPage() {
         guard pages.isEmpty else { return }
         loadNextPage()

diff --git a/Cavy/Views/Screens/Listing/ListingView.swift b/Cavy/Views/Screens/Listing/ListingView.swift
@@ -10,12 +10,19 @@ import SwiftUI
 struct ListingView: View {
     @Environment(\.lemmyAPIClient) var client
     let posts: [CavyPost]
-    init(_ posts: [CavyPost]) {
+    let isNextPageLoading: Bool
+    let onLoadNextPage: (() -> Void)?
+
+    init(_ posts: [CavyPost], isNextPageLoading: Bool = false, onLoadNextPage: (() -> Void)? = nil) {
         self.posts = posts
+        self.isNextPageLoading = isNextPageLoading
+        self.onLoadNextPage = onLoadNextPage
     }
 
-    init(_ postListing: CavyPostListing) {
-        self.posts = postListing.cavyPosts
+    init(_ postListing: CavyPostListing, isNextPageLoading: Bool = false, onLoadNextPage: (() -> Void)? = nil) {
+        self.init(postListing.cavyPosts,
+                  isNextPageLoading: isNextPageLoading,
+                  onLoadNextPage: onLoadNextPage)
     }
 
     var body: some View {
@@ -35,6 +42,15 @@ struct ListingView: View {
                 }
                 .listRowInsets(EdgeInsets(top: 4.0, leading: 8.0, bottom: 4.0, trailing: 8.0))
             }
+
+            HStack(alignment: .center) {
+                VStack(alignment: .center) {
+                    if isNextPageLoading { ProgressView() }
+                }
+            }
+            .frame(height: 80, alignment: .center)
+            .frame(maxWidth: .infinity)
+            .onAppear(perform: { onLoadNextPage?() })
         }
         .listStyle(PlainListStyle())
     }