109 lines
2.9 KiB
Swift
109 lines
2.9 KiB
Swift
//
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// ReorderableForEach.swift
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//
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//
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// Created by MainasuK on 2022-5-23.
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//
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import SwiftUI
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import UniformTypeIdentifiers
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// Ref
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// https://stackoverflow.com/a/68963988/3797903
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struct ReorderableForEach<Content: View, Item: Identifiable & Equatable & NSItemProviderWriting & TypeIdentifiedItemProvider>: View {
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@State var currentReorderItem: Item? = nil
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@State var isCurrentReorderItemOutside: Bool = false
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@Binding var items: [Item]
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@ViewBuilder let content: (Binding<Item>) -> Content
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var body: some View {
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ForEach($items) { $item in
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content($item)
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.zIndex(currentReorderItem == item ? 1 : 0)
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.onDrop(
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of: [Item.typeIdentifier],
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delegate: DropRelocateDelegate(
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item: item,
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items: $items,
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current: $currentReorderItem,
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isOutside: $isCurrentReorderItemOutside
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)
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)
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.onDrag {
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currentReorderItem = item
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isCurrentReorderItemOutside = false
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return NSItemProvider(object: item)
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}
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}
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.onDrop(
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of: [Item.typeIdentifier],
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delegate: DropOutsideDelegate(
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current: $currentReorderItem,
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isOutside: $isCurrentReorderItemOutside
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)
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)
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}
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}
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struct DropRelocateDelegate<Item: Equatable>: DropDelegate {
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let item: Item
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@Binding var items: [Item]
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@Binding var current: Item?
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@Binding var isOutside: Bool
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func dropEntered(info: DropInfo) {
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guard item != current, let current = current else { return }
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guard let from = items.firstIndex(of: current), let to = items.firstIndex(of: item) else { return }
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if items[to] != current {
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withAnimation {
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items.move(
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fromOffsets: IndexSet(integer: from),
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toOffset: to > from ? to + 1 : to
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)
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}
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}
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}
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func dropUpdated(info: DropInfo) -> DropProposal? {
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DropProposal(operation: .move)
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}
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func performDrop(info: DropInfo) -> Bool {
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current = nil
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isOutside = false
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return true
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}
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}
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struct DropOutsideDelegate<Item: Equatable>: DropDelegate {
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@Binding var current: Item?
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@Binding var isOutside: Bool
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func dropEntered(info: DropInfo) {
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isOutside = false
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}
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func dropExited(info: DropInfo) {
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isOutside = true
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}
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func dropUpdated(info: DropInfo) -> DropProposal? {
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return DropProposal(operation: .cancel)
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}
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func performDrop(info: DropInfo) -> Bool {
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current = nil
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isOutside = false
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return false
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}
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}
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public protocol TypeIdentifiedItemProvider {
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static var typeIdentifier: String { get }
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}
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