Annotations Overview

Foxit PDF SDK for Android supports most PDF annotation types through the Core SDK, including create, property access, appearance generation, and rendering.

Built-in annotations in UI Extensions

If you use the full reader (UI Extensions), common annotations (highlight, note, drawing, stamp, etc.) are available from the toolbar without extra code. This guide focuses on programmatic annotation control.

Annotation Types

Annotation Type	Constant	Description	Markup	SDK Support
Text (Note)	Annot.e_Note	Note / text comment	Yes	Supported
Link	Annot.e_Link	Hyperlink	No	Supported
FreeText	Annot.e_FreeText	Free text (typewriter/text box/callout)	Yes	Supported
Line	Annot.e_Line	Line / arrow	Yes	Supported
Square	Annot.e_Square	Rectangle	Yes	Supported
Circle	Annot.e_Circle	Circle / ellipse	Yes	Supported
Polygon	Annot.e_Polygon	Polygon	Yes	Supported
PolyLine	Annot.e_PolyLine	Polyline	Yes	Supported
Highlight	Annot.e_Highlight	Text highlight	Yes	Supported
Underline	Annot.e_Underline	Underline	Yes	Supported
Squiggly	Annot.e_Squiggly	Squiggly underline	Yes	Supported
StrikeOut	Annot.e_StrikeOut	Strikethrough	Yes	Supported
Stamp	Annot.e_Stamp	Stamp	Yes	Supported
Caret	Annot.e_Caret	Caret	Yes	Supported
Ink	Annot.e_Ink	Freehand ink	Yes	Supported
Popup	Annot.e_Popup	Popup for annotation content	No	Supported
FileAttachment	Annot.e_FileAttachment	File attachment	Yes	Supported
Sound	Annot.e_Sound	Sound	Yes	Not supported
Movie	Annot.e_Movie	Movie	No	Not supported
Widget	Annot.e_Widget	Form widget	No	Supported
Screen	Annot.e_Screen	Screen / media	No	Supported
PrinterMark	Annot.e_PrinterMark	Printer mark	No	Not supported
TrapNet	Annot.e_TrapNet	Trap net	No	Not supported
Watermark	Annot.e_Watermark	Watermark annotation	No	Not supported
3D	Annot.e_3D	3D	No	Not supported
Redact	Annot.e_Redact	Redaction	Yes	Supported

INFO

The SDK also supports custom PSI (Pressure Sensitive Ink, Annot.e_PSInk), not defined in the PDF spec, often used for handwriting.

The SDK does not support the PDF Watermark annotation type, but supports watermarks as page content—see Watermarks.

Class Hierarchy

Annot                     ← Base for all annotations
├── Markup                ← Markup features (title, subject, opacity, replies, grouping, etc.)
│   ├── TextMarkup        ← Highlight / Underline / StrikeOut / Squiggly
│   ├── FreeText
│   ├── Note
│   ├── Line
│   ├── Square
│   ├── Circle
│   ├── Ink
│   ├── Stamp
│   ├── Caret
│   ├── FileAttachment
│   └── Redact
├── Link
├── Screen
├── Widget
└── Popup

Annot Base — Common Properties

Method	Description
getType()	Type constant (e.g. Annot.e_Note)
getPage()	Page
getRect() / setRect(RectF)	Bounding rect
move(RectF)	Move
getContent() / setContent(String)	Text content
getBorderColor() / setBorderColor(int)	Border color
getBorderInfo() / setBorderInfo(BorderInfo)	Border width, style, dash
getFlags() / setFlags(int)	Flags (hidden, locked, etc.)
getUniqueID() / setUniqueID(String)	Unique ID
getModifiedDateTime() / setModifiedDateTime(DateTime)	Modified time
resetAppearanceStream()	Regenerate appearance (required after property changes)
isEmpty()	Empty check

Important

Call resetAppearanceStream() after changing properties so appearance updates take effect.

Markup Base — Extended Properties

Method	Description
getTitle() / setTitle(String)	Author/title
getSubject() / setSubject(String)	Subject
getOpacity() / setOpacity(float)	Opacity (0.0 ~ 1.0)
getIntent() / setIntent(String)	Intent (e.g. FreeText subtypes)
getCreationDateTime() / setCreationDateTime(DateTime)	Creation time
getPopup() / setPopup(Popup)	Popup
getReplyCount()	Reply count
getReply(int) / addReply() / removeReply(int)	Replies (Note type)
removeAllReplies()	Remove all replies
isGrouped()	In a group
getGroupHeader() / getGroupElements() / ungroup()	Grouping
getStateAnnots(int) / addStateAnnot(...)	State annotations

Create Annotations

Use PDFPage.addAnnot():

import com.foxit.sdk.common.fxcrt.RectF;
import com.foxit.sdk.pdf.PDFDoc;
import com.foxit.sdk.pdf.PDFPage;
import com.foxit.sdk.pdf.annots.Annot;
import com.foxit.sdk.pdf.annots.Note;

PDFDoc doc = new PDFDoc("path/to/Sample.pdf");
doc.load(null);
PDFPage page = doc.getPage(0);

RectF rect = new RectF(100, 100, 130, 130);
Note note = new Note(page.addAnnot(Annot.e_Note, rect));

note.setIconName("Comment");
note.setBorderColor(0xff0000ff);
note.setContent("这是一条便笺注释。");

note.resetAppearanceStream();

doc.saveAs("path/to/output.pdf", PDFDoc.e_SaveFlagNormal);

Delete Annotations

PDFPage page = doc.getPage(0);
Annot annot = page.getAnnot(0);
if (annot != null && !annot.isEmpty()) {
    page.removeAnnot(annot);
}

Annotation Event Listener

Register AnnotEventListener via UI Extensions DocumentManager:

import com.foxit.sdk.pdf.PDFPage;
import com.foxit.sdk.pdf.annots.Annot;
import com.foxit.uiextensions.UIExtensionsManager;
import com.foxit.uiextensions.annots.AnnotEventListener;

AnnotEventListener listener = new AnnotEventListener() {
    @Override
    public void onAnnotAdded(PDFPage page, Annot annot) {
    }

    @Override
    public void onAnnotWillDelete(PDFPage page, Annot annot) {
    }

    @Override
    public void onAnnotDeleted(PDFPage page, Annot annot) {
    }

    @Override
    public void onAnnotModified(PDFPage page, Annot annot) {
    }

    @Override
    public void onAnnotChanged(Annot lastAnnot, Annot currentAnnot) {
    }
};

UIExtensionsManager uiExtensionsManager = ...;
uiExtensionsManager.getDocumentManager().registerAnnotEventListener(listener);

NOTE

Use unregisterAnnotEventListener(listener) to unregister. Unregister when the Activity is destroyed to avoid leaks.

More Annotation Types

• Text Markup — Highlight, underline, strikethrough, squiggly
• Note and FreeText — Note, typewriter, text box, callout, caret
• Shapes and Drawing — Line, rectangle, circle, polygon, polyline, ink
• Stamps — Standard and custom stamps
• Links — URI and go-to page
• Redaction — Create and apply redaction
• Import and Export — FDF/XFDF and flattening