Custom PDF Bookmark Provider in Swift for iOS

1
//
2
//  Copyright © 2018-2025 PSPDFKit GmbH. All rights reserved.
3
//
4
//  The Nutrient sample applications are licensed with a modified BSD license.
5
//  Please see License for details. This notice may not be removed from this file.
6
//
7

8
import PSPDFKit
9
import PSPDFKitUI
10

11
class CustomBookmarkProviderExample: Example {
12
    override init() {
13
        super.init()
14

15
        title = "Custom Bookmark Provider"
16
        contentDescription = "Shows how to use a custom bookmark provider using a plist file"
17
        category = .subclassing
18
        priority = 250
19
    }
20

21
    override func invoke(with delegate: ExampleRunnerDelegate) -> UIViewController {
22
        let document = AssetLoader.writableDocument(for: .annualReport, overrideIfExists: false)
23
        document.bookmarkManager?.provider = [BookmarkParser()]
24

25
        let controller = PDFViewController(document: document) {
26
            $0.bookmarkSortOrder = .custom
27
        }
28
        controller.navigationItem.setRightBarButtonItems([controller.thumbnailsButtonItem, controller.outlineButtonItem, controller.searchButtonItem, controller.bookmarkButtonItem], for: .document, animated: false)
29
        return controller
30
    }
31
}
32

33
class BookmarkParser: NSObject, BookmarkProvider {
34
    struct CustomBookmark: Codable {
35
        let identifier: String
36
        let pageIndex: PageIndex
37
        let name: String
38
        let sortKey: Int
39

40
        private enum CodingKeys: String, CodingKey {
41
            case identifier
42
            case pageIndex
43
            case name
44
            case sortKey
45
        }
46

47
        init(bookmark: Bookmark) {
48
            self.identifier = bookmark.identifier
49
            self.pageIndex = bookmark.pageIndex
50
            self.name = bookmark.name?.replacingOccurrences(of: "\"", with: "'") ?? String()
51
            if let sortKey = bookmark.sortKey {
52
                self.sortKey = sortKey.intValue
53
            } else {
54
                self.sortKey = 0
55
            }
56
        }
57

58
        func encode(to encoder: Encoder) throws {
59
            var container = encoder.container(keyedBy: CodingKeys.self)
60
            try container.encode(identifier, forKey: .identifier)
61
            try container.encode(pageIndex, forKey: .pageIndex)
62
            try container.encode(name, forKey: .name)
63
            try container.encode(sortKey, forKey: .sortKey)
64
        }
65

66
        init(from decoder: Decoder) throws {
67
            let values = try decoder.container(keyedBy: CodingKeys.self)
68
            identifier = try values.decode(String.self, forKey: .identifier)
69
            pageIndex = try values.decode(PageIndex.self, forKey: .pageIndex)
70
            name = try values.decode(String.self, forKey: .name)
71
            sortKey = try values.decode(Int.self, forKey: .sortKey)
72
        }
73
    }
74

75
    var bookmarks: [Bookmark] {
76
        return self.bookmarkData
77
    }
78

79
    var bookmarkData: [Bookmark]
80

81
    override init() {
82
        self.bookmarkData = BookmarkParser.bookmarkDataFromFile()
83
        super.init()
84
    }
85

86
    func add(_ bookmark: Bookmark) -> Bool {
87
        print("Add Bookmark: \(bookmark)")
88
        let index = bookmarkData.firstIndex(of: bookmark)
89
        if index == nil || index == NSNotFound {
90
            bookmarkData.append(bookmark)
91
        } else {
92
            bookmarkData[index!] = bookmark
93
        }
94
        return true
95
    }
96

97
    func remove(_ bookmark: Bookmark) -> Bool {
98
        print("Remove Bookmark: \(bookmark)")
99
        if bookmarkData.contains(bookmark) {
100
            while let elementIndex = bookmarkData.firstIndex(of: bookmark) {
101
                bookmarkData.remove(at: elementIndex)
102
            }
103
            return true
104
        } else {
105
            return false
106
        }
107
    }
108

109
    func save() {
110
        print("Save bookmarks.")
111
        let customBookmarks = bookmarkData.map({ return CustomBookmark(bookmark: $0) })
112
        let jsonData = try? PropertyListEncoder().encode(customBookmarks)
113
        try? jsonData?.write(to: BookmarkParser.bookmarkURL()!, options: Data.WritingOptions.atomic)
114
    }
115

116
    // MARK: Helpers
117

118
    class func bookmarkURL() -> URL? {
119
        let applicationSupport = try? FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
120
        let fileURL = applicationSupport?.appendingPathComponent("customBookmarksProvider").appendingPathExtension("plist")
121
        return fileURL
122
    }
123

124
    class func bookmarkDataFromFile() -> [Bookmark] {
125
        var bookmarkData = [Bookmark]()
126

127
        guard let jsonData = try? Data(contentsOf: BookmarkParser.bookmarkURL()!) else {
128
            return bookmarkData
129
        }
130

131
        let customBookmark: [CustomBookmark] = try! PropertyListDecoder().decode(Array.self, from: jsonData)
132
        bookmarkData = customBookmark.map({
133
            let identifier = $0.identifier
134
            let pageIndex = $0.pageIndex
135
            let name = $0.name
136
            let sortKey = NSNumber(value: $0.sortKey)
137
            let action = GoToAction(pageIndex: PageIndex(pageIndex))
138
            return Bookmark(identifier: identifier, action: action, name: name, sortKey: sortKey)
139
        })
140

141
        return bookmarkData
142
    }
143
}