Guides

Viewer

The ComPDF Flutter SDK provides reader-level callbacks through CPDFReaderWidget. Use these callbacks for viewer lifecycle and UI events.

Available Callbacks

Callback	Trigger Timing	Payload
onPageChanged	Current page changes	int pageIndex
onSaveCallback	Document save completes	No payload
onFillScreenChanged	Fullscreen state changes	bool isFullScreen
onTapMainDocAreaCallback	User taps the main PDF page area	No payload
onPageEditDialogBackPress	User taps the back button in the page edit dialog	No payload
onIOSClickBackPressed	iOS top-left reader back button is tapped	No payload
onSearchBackButtonTappedCallback	User taps the back button in the search view	No payload
onAddWatermarkDialogDismissedCallback	Add watermark dialog is dismissed	No payload

Example Usage

CPDFReaderWidget(
  document: documentPath,
  configuration: configuration,
  onCreated: (controller) {
    // Store the controller if listener events are needed later.
  },
  onPageChanged: (int pageIndex) {
    debugPrint('Current page: $pageIndex');
  },
  onSaveCallback: () {
    debugPrint('Document saved successfully');
  },
  onFillScreenChanged: (bool isFullScreen) {
    debugPrint('Is full screen: $isFullScreen');
  },
  onTapMainDocAreaCallback: () {
    debugPrint('Main document area tapped');
  },
  onPageEditDialogBackPress: () {
    debugPrint('Back button pressed in page edit dialog');
  },
  onIOSClickBackPressed: () {
    debugPrint('iOS back button pressed');
  },
  onSearchBackButtonTappedCallback: () {
    debugPrint('Search back button tapped');
  },
  onAddWatermarkDialogDismissedCallback: () {
    debugPrint('Add watermark dialog dismissed');
  },
);

Note

• onSearchBackButtonTappedCallback is useful when you manage search state on the Flutter side.
• onAddWatermarkDialogDismissedCallback fires after the add watermark panel closes. Use it to restore custom UI state or refresh watermark-related controls.