> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/android/bookmarks/outline.md).

# Outline tree

Learn how to work with an outline tree in Android using a UI component or API guide. Display and navigate PDF bookmarks programmatically with code samples and examples. The Apryse Android SDK streamli

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.

{% tabs %}
{% tab title="UI component" %}

## Display outlines & bookmarks in Android

The [`OutlineDialogFragment`](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/controls/OutlineDialogFragment.html) displays a document outline (containing PDF `Bookmarks` that can be used to navigate the PDF document by selecting a bookmark item.

![](https://226546913-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F0QItsdFBmuuL9ezHimHy%2Fuploads%2Fgit-blob-70d682efd843654067aaa1eda10edfa72af76763%2Fcf7d5120d7c199b14fec80aefd804b573704dac8-810x1710.png?alt=media)

## Show outline dialog

To show an outline dialog fragment in your activity, create a new instance of [`OutlineDialogFragment`](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/controls/OutlineDialogFragment.html) by calling `newInstance()` and setting the [`PDFViewCtrl`](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/PDFViewCtrl.html):

{% tabs %}
{% tab title="Java" %}
{% code lineNumbers="true" %}

```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;
}
```

{% endcode %}
{% endtab %}

{% tab title="Kotlin" %}
{% code lineNumbers="true" %}

```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
}
```

{% endcode %}
{% endtab %}
{% endtabs %}

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`](https://sdk.apryse.com/api/android/javadoc/reference/com/pdftron/pdf/controls/OutlineDialogFragment.html) is clicked by calling `setOutlineDialogListener(OutlineDialogListener)`.
{% endtab %}

{% tab title="API guide" %}

## API to programmatically read, edit & create outlines / bookmarks

To navigate an outline tree and print its result.

{% tabs %}
{% tab title="Java" %}
{% code lineNumbers="true" %}

```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);
```

{% endcode %}
{% endtab %}

{% tab title="Kotlin" %}
{% code lineNumbers="true" %}

```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)
```

{% endcode %}
{% endtab %}
{% endtabs %}

[Read, add, edit PDF outlines and bookmarks](/android/get-started/samples.md#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.
{% endtab %}
{% endtabs %}


---

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