Programmatically Go To PDF Outline in Swift for iOS

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//
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//  Copyright © 2017-2025 PSPDFKit GmbH. All rights reserved.
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//
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//  The Nutrient sample applications are licensed with a modified BSD license.
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//  Please see License for details. This notice may not be removed from this file.
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//
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import PSPDFKit
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import PSPDFKitUI
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class ProgrammaticallyGoToOutlineExample: Example {
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    override init() {
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        super.init()
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        title = "Programmatically Go to a Specific Outline."
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        category = .controllerCustomization
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        priority = .max
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    }
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    override func invoke(with delegate: ExampleRunnerDelegate) -> UIViewController {
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        let document = AssetLoader.document(for: .welcome)
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        let controller = PDFViewController(document: document)
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        // Check that the PDF has an outline.
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        guard let outline = document.outline else {
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            return controller
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        }
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        guard let matchingOutline = matchingOutlineByTitle(outline: outline, title: "Swift 4") else {
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            return controller
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        }
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        controller.setPageIndex(matchingOutline.pageIndex, animated: false)
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        return controller
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    }
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    // Recursive function to find the matching outline element by title.
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    private func matchingOutlineByTitle(outline: OutlineElement, title: String) -> OutlineElement! {
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        // Return the passed outline if the title matches
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        if outline.title == title {
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            return outline
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        }
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        if let children = outline.children {
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            // Loop through the outline's children to to find a matching outline
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            for child in children {
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                // Match found
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                if let match = matchingOutlineByTitle(outline: child, title: title) {
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                    return match
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                }
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            }
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        }
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        return nil
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    }
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}