Outline tree

There are two options to working with an outline tree. First is using a UI component that provides tools to set a bookmark or display the outline. Second is an API guide to programmatically read outline items.

UI component

Display outlines & bookmarks in Android

The OutlineDialogFragment displays a document outline (containing PDF Bookmarks that can be used to navigate the PDF document by selecting a bookmark item.

Show outline dialog

To show an outline dialog fragment in your activity, create a new instance of OutlineDialogFragment by calling newInstance() and setting the PDFViewCtrl:

Java

BookmarksDialogFragment showBookmarksDialog(FragmentManager fragmentManager, PDFViewCtrl pdfViewCtrl) {
    DialogFragmentTab outlineDialog = new DialogFragmentTab(
        UserBookmarkDialogFragment.class,
        BookmarksTabLayout.TAG_TAB_OUTLINE,
        null,
        "Outline",
        "Bookmarks Dialog",
        null);
    ArrayList<DialogFragmentTab> dialogFragmentTabs = new ArrayList<>();
    dialogFragmentTabs.add(outlineDialog);

    BookmarksDialogFragment bookmarksDialog = BookmarksDialogFragment.newInstance();
    bookmarksDialog.setPdfViewCtrl(pdfViewCtrl)
        .setDialogFragmentTabs(dialogFragmentTabs);
    bookmarksDialog.setStyle(DialogFragment.STYLE_NO_TITLE, R.style.PDFTronAppTheme);   
    bookmarksDialog.show(fragmentManager, "bookmarks_dialog");
    return bookmarksDialog;
}

Kotlin

fun showBookmarksDialog(fragmentManager: FragmentManager, pdfViewCtrl: PDFViewCtrl): BookmarksDialogFragment {
    val outlineDialog = DialogFragmentTab(
        UserBookmarkDialogFragment::class.java!!,
        BookmarksTabLayout.TAG_TAB_OUTLINE, null,
        "Outline",
        "Bookmarks Dialog", null)
    val dialogFragmentTabs = ArrayList<DialogFragmentTab>()
    dialogFragmentTabs.add(outlineDialog)
    
    val bookmarksDialog = BookmarksDialogFragment.newInstance()
    bookmarksDialog.setPdfViewCtrl(pdfViewCtrl)
                   .setDialogFragmentTabs(dialogFragmentTabs)
    bookmarksDialog.setStyle(DialogFragment.STYLE_NO_TITLE, R.style.PDFTronAppTheme)
    bookmarksDialog.show(fragmentManager, "bookmarks_dialog")
    return bookmarksDialog
}

You can also set the current bookmark using setCurrentBookmark(Bookmark).

Listener

You can set a listener to be notified when an item in an OutlineDialogFragment is clicked by calling setOutlineDialogListener(OutlineDialogListener).

API guide

API to programmatically read, edit & create outlines / bookmarks

To navigate an outline tree and print its result.

Java

void PrintIndent(Bookmark item) throws PDFNetException {
  int ident = item.getIndent() - 1;
  for (int i = 0; i < ident; ++i) {
    System.out.print("  ");
  }
}
void PrintOutlineTree(Bookmark item) throws PDFNetException {
  for (; item.isValid(); item = item.getNext()) {
    PrintIndent(item);
    System.out.print((item.isOpen() ? "- " : "+ ") + item.getTitle() + " ACTION -> ");
    if (item.hasChildren()) {
      PrintOutlineTree(item.getFirstChild());
    }
  }
}
PDFDoc doc = new PDFDoc(filename);
Bookmark root = doc.getFirstBookmark();
PrintOutlineTree(root);

Kotlin

@Throws(PDFNetException::class)
fun PrintIndent(item: Bookmark) {
  val ident = item.indent - 1
  for (i in 0 until ident) {
    print("  ")
  }
}
@Throws(PDFNetException::class)
fun PrintOutlineTree(item: Bookmark) {
  var item = item
  while (item.isValid) {
    PrintIndent(item)
    print((if (item.isOpen) "- " else "+ ") + item.title + " ACTION -> ")
    if (item.hasChildren()) {
      PrintOutlineTree(item.firstChild)
    }
    item = item.next
  }
}
val doc = PDFDoc(filename)
val root = doc.firstBookmark
PrintOutlineTree(root)

Read, add, edit PDF outlines and bookmarks Full code sample which illustrates how to read and edit existing outline items and create new bookmarks using the high-level API.

About outline tree

A PDF document may display a document outline on the screen, allowing the user to navigate interactively from one part of the document to another. The outline consists of a tree-structured hierarchy of Bookmarks (sometimes called outline items), which serve as a "visual table of contents" to display the document's structure to the user.

Each Bookmark has a title that appears on screen, and an Action that specifies what happens when a user clicks on the Bookmark. The typical Action for a user-created Bookmark is to move to another location in the current document — although any Action can be specified.