Added shouldNavigateToLink on NavigatorDelegate

CHANGELOG.md

@@ -12,8 +12,9 @@ All notable changes to this project will be documented in this file. Take a look
 
 * The `PublicationSpeechSynthesizer` (TTS) now supports background playback by default.
     * You will need to enable the **Audio Background Mode** in your app's build info.
-* The EPUB navigator can now render a custom reading order (contributed by [@chrfalch](https://github.com/readium/swift-toolkit/pull/332)).
-    * This is useful when displaying a non-linear resource.
+* Support for non-linear EPUB resources with an opt-in in reading apps (contributed by @chrfalch in [#332](https://github.com/readium/swift-toolkit/pull/332) and [#331](https://github.com/readium/swift-toolkit/pull/331)).
+    1. Override loading non-linear resources with `VisualNavigatorDelegate.navigator(_:shouldNavigateToLink:)`.
+    2. Present a new `EPUBNavigatorViewController` by providing a custom `readingOrder` with only this resource to the constructor.
 
 ### Fixed
 

Sources/Navigator/EPUB/EPUBNavigatorViewController.swift

@@ -985,6 +985,11 @@ extension EPUBNavigatorViewController: EPUBSpreadViewDelegate {
     }
 
     func spreadView(_ spreadView: EPUBSpreadView, didTapOnInternalLink href: String, clickEvent: ClickEvent?) {
+        guard let link = publication.link(withHREF: href)?.copy(href: href) else {
+            log(.warning, "Cannot find link with HREF: \(href)")
+            return
+        }
+
         // Check to see if this was a noteref link and give delegate the opportunity to display it.
         if
             let clickEvent = clickEvent,
@@ -994,15 +999,20 @@ extension EPUBNavigatorViewController: EPUBSpreadViewDelegate {
         {
             if !delegate.navigator(
                 self,
-                shouldNavigateToNoteAt: Link(href: href, type: "text/html"),
+                shouldNavigateToNoteAt: link,
                 content: note,
                 referrer: referrer
             ) {
                 return
             }
         }
 
-        go(to: Link(href: href))
+        // Ask if we should navigate to the link
+        if let delegate = delegate, !delegate.navigator(self, shouldNavigateToLink: link) {
+            return
+        }
+
+        go(to: link)
     }
 
     /// Checks if the internal link is a noteref, and retrieves both the referring text of the link and the body of the note.

Sources/Navigator/VisualNavigator.swift

@@ -107,6 +107,12 @@ public protocol VisualNavigatorDelegate: NavigatorDelegate {
     /// Called when the user released a key and it was not handled by the
     /// resource.
     func navigator(_ navigator: VisualNavigator, didReleaseKey event: KeyEvent)
+
+    /// Called when the user taps on an internal link.
+    ///
+    /// Return `true` to navigate to the link, or `false` if you intend to
+    /// present the link yourself
+    func navigator(_ navigator: VisualNavigator, shouldNavigateToLink link: Link) -> Bool
 }
 
 public extension VisualNavigatorDelegate {
@@ -125,4 +131,8 @@ public extension VisualNavigatorDelegate {
     func navigator(_ navigator: VisualNavigator, didReleaseKey event: KeyEvent) {
         // Optional
     }
+
+    func navigator(_ navigator: VisualNavigator, shouldNavigateToLink link: Link) -> Bool {
+        true
+    }
 }