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Chris
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Merge pull request #10 from crelies/dev
Pagination is now implemented as a modifier 🚀
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‎README.md

+132-40
Original file line numberDiff line numberDiff line change
@@ -37,52 +37,39 @@ AdvancedList(yourData, content: { item in
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### 📄 Pagination
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The `Pagination` is implemented as a class (conforming to `ObservableObject`) so the `AdvancedList` can observe it.
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It has three different states: `error`, `idle` and `loading`. If the `state` of the `Pagination` changes the `AdvancedList` updates itself to show or hide the state related view (`ErrorView` for state `.error(Error)` or `LoadingView` for state `.loading`, `.idle` will display nothing). Update the `state` if you start loading (`.loading`), stop loading ( `.idle`) or if an error occurred (`.error(Error)`) so the `AdvancedList` can render the appropriate view.
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The `Pagination` functionality is now (>= `5.0.0`) implemented as a `modifier`.
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It has three different states: `error`, `idle` and `loading`. If the `state` of the `Pagination` changes the `AdvancedList` displays the view created by the view builder of the specified pagination object (`AdvancedListPagination`). Keep track of the current pagination state by creating a local state variable (`@State`) of type `AdvancedListPaginationState`. Use this state variable in the `content` `ViewBuilder` of your pagination configuration object to determine which view should be displayed in the list (see the example below).
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If you want to use pagination you can choose between the `lastItemPagination` and the `thresholdItemPagination`. Both concepts are described [here](https://github.com/crelies/ListPagination). Just pass `.lastItemPagination` or `.thresholdItemPagination` including the required parameters to the `AdvancedList` initializer.
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If you want to use pagination you can choose between the `lastItemPagination` and the `thresholdItemPagination`. Both concepts are described [here](https://github.com/crelies/ListPagination). Just specify the type of the pagination when adding the `.pagination` modifier to your `AdvancedList`.
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Both pagination types require
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- an **ErrorView** and a **LoadingView** (**ViewBuilder**)
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- a block (**shouldLoadNextPage**) which is called if the `last or threshold item appeared` and
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- the initial state (**AdvancedListPaginationState**) of the pagination which determines the visibility of the pagination state related view.
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The `thresholdItemPagination` expects an offset parameter (number of items before the last item) to determine the threshold item.
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**The ErrorView or LoadingView will only be visible below the List if the last item of the List appeared! That way the user is only interrupted if needed.**
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**Skip pagination setup by using `.noPagination`.**
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**The view created by the `content` `ViewBuilder` of your pagination configuration object will only be visible below the List if the last item of the List appeared! That way the user is only interrupted if needed.**
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**Example:**
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```swift
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private(set) lazy var pagination: AdvancedListPagination<AnyView, AnyView> = {
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.thresholdItemPagination(errorView: { error in
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AnyView(
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VStack {
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Text(error.localizedDescription)
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.lineLimit(nil)
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.multilineTextAlignment(.center)
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Button(action: {
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// load current page again
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}) {
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Text("Retry")
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}.padding()
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}
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)
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}, loadingView: {
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AnyView(
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VStack {
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Divider()
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Text("Loading...")
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}
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)
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}, offset: 25, shouldLoadNextPage: {
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// load next page
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}, state: .idle)
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}()
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@State private var paginationState: AdvancedListPaginationState = .idle
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AdvancedList(...)
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.pagination(.init(type: .lastItem, shouldLoadNextPage: {
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paginationState = .loading
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DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
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items.append(contentsOf: moreItems)
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paginationState = .idle
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}
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}) {
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switch paginationState {
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case .idle:
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EmptyView()
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case .loading:
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if #available(iOS 14.0, *) {
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ProgressView()
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} else {
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Text("Loading ...")
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}
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case let .error(error):
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Text(error.localizedDescription)
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}
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})
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```
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### 📁 Move and 🗑️ delete items
@@ -297,3 +284,108 @@ AdvancedList(yourData, content: { item in
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}
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```
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</details>
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<details>
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<summary>Migration 4.0 -> 5.0</summary>
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`Pagination` is now implemented as a `modifier` 💪 And last but not least the code documentation arrived 😀
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**Before:**
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```swift
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private lazy var pagination: AdvancedListPagination<AnyView, AnyView> = {
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.thresholdItemPagination(errorView: { error in
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AnyView(
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VStack {
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Text(error.localizedDescription)
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.lineLimit(nil)
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.multilineTextAlignment(.center)
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Button(action: {
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// load current page again
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}) {
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Text("Retry")
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}.padding()
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}
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)
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}, loadingView: {
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AnyView(
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VStack {
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Divider()
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Text("Loading...")
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}
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)
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}, offset: 25, shouldLoadNextPage: {
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// load next page
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}, state: .idle)
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}()
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@State private var listState: ListState = .items
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AdvancedList(yourData, content: { item in
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Text("Item")
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}, listState: $listState, emptyStateView: {
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Text("No data")
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}, errorStateView: { error in
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VStack {
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Text(error.localizedDescription)
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.lineLimit(nil)
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Button(action: {
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// do something
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}) {
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Text("Retry")
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}
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}
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}, loadingStateView: {
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Text("Loading ...")
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}, pagination: pagination)
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```
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**After:**
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```swift
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@State private var listState: ListState = .items
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@State private var paginationState: AdvancedListPaginationState = .idle
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AdvancedList(yourData, content: { item in
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Text("Item")
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}, listState: $listState, emptyStateView: {
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Text("No data")
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}, errorStateView: { error in
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VStack {
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Text(error.localizedDescription)
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.lineLimit(nil)
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Button(action: {
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// do something
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}) {
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Text("Retry")
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}
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}
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}, loadingStateView: {
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Text("Loading ...")
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})
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.pagination(.init(type: .lastItem, shouldLoadNextPage: {
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paginationState = .loading
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DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
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items.append(contentsOf: moreItems)
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paginationState = .idle
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}
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}) {
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switch paginationState {
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case .idle:
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EmptyView()
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case .loading:
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if #available(iOS 14.0, *) {
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ProgressView()
383+
} else {
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Text("Loading ...")
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}
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case let .error(error):
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Text(error.localizedDescription)
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}
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})
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```
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</details>

‎Sources/AdvancedList/private/Models/AdvancedListPaginationType.swift

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This file was deleted.

‎Sources/AdvancedList/private/Models/AnyAdvancedListPagination.swift

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//
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// AnyAdvancedListPagination.swift
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//
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//
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// Created by Christian Elies on 31.07.20.
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//
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import SwiftUI
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struct AnyAdvancedListPagination {
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let type: AdvancedListPaginationType
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let shouldLoadNextPage: () -> Void
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let content: () -> AnyView
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init<Content: View>(_ pagination: AdvancedListPagination<Content>) {
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type = pagination.type
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shouldLoadNextPage = pagination.shouldLoadNextPage
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content = { AnyView(pagination.content()) }
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}
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}

‎Sources/AdvancedList/private/Models/ListState+error.swift

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//
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// ListState+error.swift
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//
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//
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// Created by Christian Elies on 02.08.20.
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//
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extension ListState {
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var error: Swift.Error? {
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guard case let ListState.error(error) = self else {
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return nil
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}
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return error
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}
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}

‎Sources/AdvancedList/public/Models/AdvancedListPagination.swift

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@@ -5,56 +5,27 @@
55
// Created by Christian Elies on 15.08.19.
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//
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import Combine
98
import SwiftUI
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public final class AdvancedListPagination<ErrorView: View, LoadingView: View>: NSObject, ObservableObject {
12-
let errorView: (Error) -> ErrorView
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let loadingView: () -> LoadingView
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/// Represents the pagination configuration.
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public struct AdvancedListPagination<Content: View> {
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let type: AdvancedListPaginationType
1513
let shouldLoadNextPage: () -> Void
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17-
public let objectWillChange = PassthroughSubject<Void, Never>()
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public var state: AdvancedListPaginationState {
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didSet {
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objectWillChange.send()
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}
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}
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init(@ViewBuilder errorView: @escaping (Error) -> ErrorView, @ViewBuilder loadingView: @escaping () -> LoadingView, type: AdvancedListPaginationType, shouldLoadNextPage: @escaping () -> Void, state: AdvancedListPaginationState) {
26-
self.errorView = errorView
27-
self.loadingView = loadingView
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let content: () -> Content
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/// Initializes the pagination configuration with the given values.
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///
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/// - Parameters:
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/// - type: The type of the pagination, choose between `lastItem` or `thresholdItem`.
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/// - shouldLoadNextPage: A closure that is called everytime the end of a page is reached.
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/// - content: A closure providing a `View` which should be displayed at the end of a page.
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public init(
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type: AdvancedListPaginationType,
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shouldLoadNextPage: @escaping () -> Void,
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@ViewBuilder content: @escaping () -> Content
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) {
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self.type = type
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self.shouldLoadNextPage = shouldLoadNextPage
30-
self.state = state
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}
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}
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extension AdvancedListPagination {
35-
public static func lastItemPagination(@ViewBuilder errorView: @escaping (Error) -> ErrorView, @ViewBuilder loadingView: @escaping () -> LoadingView, shouldLoadNextPage: @escaping () -> Void, state: AdvancedListPaginationState) -> AdvancedListPagination {
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AdvancedListPagination(errorView: errorView,
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loadingView: loadingView,
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type: .lastItem,
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shouldLoadNextPage: shouldLoadNextPage,
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state: state)
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}
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public static func thresholdItemPagination(@ViewBuilder errorView: @escaping (Error) -> ErrorView, @ViewBuilder loadingView: @escaping () -> LoadingView, offset: Int, shouldLoadNextPage: @escaping () -> Void, state: AdvancedListPaginationState) -> AdvancedListPagination {
44-
AdvancedListPagination(errorView: errorView,
45-
loadingView: loadingView,
46-
type: .thresholdItem(offset: offset),
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shouldLoadNextPage: shouldLoadNextPage,
48-
state: state)
49-
}
50-
}
51-
52-
extension AdvancedListPagination where ErrorView == EmptyView, ErrorView == LoadingView {
53-
public static var noPagination: AdvancedListPagination {
54-
AdvancedListPagination(errorView: { _ in ErrorView() },
55-
loadingView: { LoadingView() },
56-
type: .noPagination,
57-
shouldLoadNextPage: {},
58-
state: .idle)
29+
self.content = content
5930
}
6031
}

‎Sources/AdvancedList/public/Models/AdvancedListPaginationState.swift

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@@ -7,24 +7,12 @@
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88
import Foundation
99

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public enum AdvancedListPaginationState {
11-
case error(_ error: Error)
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/// Represents the different states of a pagination.
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public enum AdvancedListPaginationState: Equatable {
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/// The error state; use this state if an error occurs while loading a page.
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case error(_ error: NSError)
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/// The idle state; use this state if no page loading is in progress.
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case idle
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/// The loading state; use this state if a page is loaded.
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case loading
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}
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extension AdvancedListPaginationState: Equatable {
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public static func ==(lhs: AdvancedListPaginationState,
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rhs: AdvancedListPaginationState) -> Bool {
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switch (lhs, rhs) {
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case (.error(let lhsError), .error(let rhsError)):
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return (lhsError as NSError) == (rhsError as NSError)
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case (.idle, .idle):
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return true
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case (.loading, .loading):
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return true
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default:
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return false
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}
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}
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}

‎Sources/AdvancedList/public/Models/AdvancedListPaginationType.swift

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1+
//
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// AdvancedListPaginationType.swift
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//
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//
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// Created by Christian Elies on 16.08.19.
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//
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/// Specifies the different pagination types.
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public enum AdvancedListPaginationType {
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/// Notifies the pagination configuration object when the last item in the list was reached.
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case lastItem
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/// Notifies the pagination configuration object when the given offset was passed.
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case thresholdItem(offset: Int)
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}

‎Sources/AdvancedList/public/Models/ListState.swift

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import Foundation
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11-
public enum ListState {
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case error(_ error: Error)
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/// Specifies the different states of an `AdvancedList`.
12+
public enum ListState: Equatable {
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/// The `error` state; displays the error view instead of the list to the user.
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case error(_ error: NSError)
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/// The `items` state (`default`); displays the items or the empty state view (if there are no items) to the user.
1316
case items
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/// The `loading` state; displays the loading state view instead of the list to the user.
1418
case loading
1519
}
16-
17-
extension ListState {
18-
var error: Error? {
19-
guard case let ListState.error(error) = self else {
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return nil
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}
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return error
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}
24-
}
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26-
extension ListState: Equatable {
27-
public static func ==(lhs: ListState, rhs: ListState) -> Bool {
28-
switch (lhs, rhs) {
29-
case (.error(let lhsError), .error(let rhsError)):
30-
return (lhsError as NSError) == (rhsError as NSError)
31-
case (.items, .items):
32-
return true
33-
case (.loading, .loading):
34-
return true
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default:
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return false
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}
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}
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}

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