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Content Editing Events and History State

Content editing uses CPDFEvent for selection changes and its History Manager for undo/redo state.

Event	Event data	Trigger
CPDFEvent.editorSelectionSelected	CPDFEditArea?	An editable text, image, or path area is selected.
CPDFEvent.editorSelectionDeselected	null	The content editor selection is cleared.

When the content editor properties panel closes, onContentEditorStyleDialogDismissedCallback returns CPDFContentEditorType. The callback can be used to synchronize application editing state and does not change the SDK's default behavior.

Scenario	Registration API	Callback parameters	Replacement rule
Content editor undo/redo state	controller.editManager.historyManager. setOnHistoryChangedListener()	int pageIndex, bool canUndo, bool canRedo	Calling the setter again replaces the previous callback.

void _onReaderCreated(CPDFReaderWidgetController controller) {
  controller.addEventListener(
    CPDFEvent.editorSelectionSelected,
    (event) => debugPrint('Selected edit area: $event'),
  );
  controller.addEventListener(
    CPDFEvent.editorSelectionDeselected,
    (_) => debugPrint('Editor selection cleared'),
  );

  controller.editManager.historyManager.setOnHistoryChangedListener(
    (pageIndex, canUndo, canRedo) {
      debugPrint(
        'Editor history: page=$pageIndex, undo=$canUndo, redo=$canRedo',
      );
    },
  );
}

editorSelectionSelected returns CPDFEditTextArea, CPDFEditImageArea, or CPDFEditArea (with type == CPDFEditAreaType.path for a path). editorSelectionDeselected always returns null; Flutter does not define a dedicated path-area subclass.

Each History Manager stores one callback. Calling setOnHistoryChangedListener() again replaces it. For the undo, redo, and state-query APIs, see Undo and Redo.

On iOS, the content editor History Listener can also run after a page change to report the state of the current page.

A History Listener reports changes that occur after registration; it does not send an initial value. Query canUndo() and canRedo() when initializing undo and redo controls:

final history = controller.editManager.historyManager;
final canUndo = await history.canUndo();
final canRedo = await history.canRedo();