Guides

Annotations

Use these callbacks to synchronize annotation property panels and observe annotation creation, selection, and undo or redo state. Annotation history uses a dedicated listener rather than CPDFEvent.

Callback or API	Parameters	Trigger
onAnnotationStyleDialogDismissedCallback	CPDFAnnotationType type	The annotation properties panel closes.
controller.annotationHistoryManager.<br/>setOnHistoryChangedListener()	bool canUndo, bool canRedo	The annotation undo/redo state changes.

CPDFReaderWidgetController.addEventListener() supports multiple callbacks for the same event. When the first listener for an event is added, the Flutter SDK asks the native SDK to start sending that event. Removing the last listener stops native delivery.

void addEventListener(CPDFEvent event, Function(dynamic) callback);

bool removeEventListener(CPDFEvent event, Function(dynamic) callback);

void removeAllEventListeners([CPDFEvent? event]);

Event Index

Event	Event data	Trigger
CPDFEvent.annotationsCreated	CPDFAnnotation	A non-form annotation is created.
CPDFEvent.annotationsSelected	CPDFAnnotation	An annotation is selected.
CPDFEvent.annotationsDeselected	CPDFAnnotation?	An annotation is deselected.
CPDFEvent.pencilDrawingCompleted	Map<String, dynamic>	A Pencil drawing is saved (iOS only).
CPDFEvent.pencilDrawingDiscarded	Map<String, dynamic>	A Pencil drawing is discarded (iOS only).

Register annotation events and the annotation History Manager after the Reader is created:

void _onReaderCreated(CPDFReaderWidgetController controller) {
  controller.addEventListener(
    CPDFEvent.annotationsCreated,
    (annotation) => debugPrint('Created: $annotation'),
  );
  controller.addEventListener(
    CPDFEvent.annotationsSelected,
    (annotation) => debugPrint('Selected: $annotation'),
  );
  controller.addEventListener(
    CPDFEvent.annotationsDeselected,
    (annotation) => debugPrint('Deselected: $annotation'),
  );

  controller.annotationHistoryManager.setOnHistoryChangedListener(
    (canUndo, canRedo) {
      debugPrint('Annotation history: undo=$canUndo, redo=$canRedo');
    },
  );
}

CPDFEvent currently covers creation and selection state. It does not report annotation updates and deletions, or save failures. To save explicitly and inspect the result, use the relevant save API instead of relying on onSaveCallback.

Pencil events are available only on iOS. Their event data provides type and pageIndex.