Pdf突出显示存储和访问

Question

我试图突出显示 pdf 的内容并保存和存储它，以便下次用户打开该 pdf 时他/她可以访问突出显示的项目。我为此使用syncfusion_flutter_pdf 包。到目前为止，我可以突出显示内容，但无法存储和访问突出显示的内容。 我的代码是：

class HomePage extends StatefulWidget {
  @override
  _HomePage createState() => _HomePage();
}

class _HomePage extends State<HomePage> {
  final GlobalKey<SfPdfViewerState> _pdfViewerKey = GlobalKey();
  PdfViewerController controller = PdfViewerController();

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Syncfusion Flutter PDF Viewer'),
        actions: <Widget>[
          IconButton(
            icon: const Icon(
              Icons.bookmark,
              color: Colors.white,
              semanticLabel: 'Bookmark',
            ),
            onPressed: () {
              _pdfViewerKey.currentState?.openBookmarkView();
            },
          ),
        ],
      ),
      body: SfPdfViewer.asset(
        'assets/name.pdf',
        controller: controller,
        onAnnotationSelected: (Annotation annotation) {
          annotation.addListener(() {});
          
        },
        onAnnotationAdded: (Annotation annotation) {
          annotation.color = Colors.yellow;
          log('selected lines ${controller.getAnnotations()}');
        },
        onAnnotationDeselected: (Annotation annotation) {
          annotation.color = Colors.white;
        },
        onAnnotationEdited: (Annotation annotation) {
          annotation.color = Colors.blue;
        },
        onAnnotationRemoved: (Annotation annotation) {},
        key: _pdfViewerKey,
      ),
    );
  }
}

我想获得存储和访问突出显示的 pdf 内容的解决方案。

Answer 1

您可以使用 saveDocument 方法将注释保存到文档中。重新打开同一文档时，突出显示的内容将被保留。

class HomePage extends StatefulWidget {
  @override
  _HomePage createState() => _HomePage();
}

class _HomePage extends State<HomePage> {
  final GlobalKey<SfPdfViewerState> _pdfViewerKey = GlobalKey();
  PdfViewerController controller = PdfViewerController();

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Syncfusion Flutter PDF Viewer'),
        actions: <Widget>[
          IconButton(
            icon: const Icon(
              Icons.save,
            ),
            onPressed: _save,
          ),
        ],
      ),
      body: FutureBuilder<File>(
          future: _getPdf(),
          builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
            if (snapshot.hasData && snapshot.data != null) {
              return SfPdfViewer.file(
                snapshot.data!,
                controller: controller,
                key: _pdfViewerKey,
                onAnnotationAdded: (annotation) {
                  annotation.author = 'Guest';
                  annotation.subject = 'Text Markup';
                },
              );
            } else {
              return const Center(child: CircularProgressIndicator());
            }
          }),
    );
  }

  Future<File> _getPdf() async {
    final Directory dir = await getTemporaryDirectory();
    final File file = File('${dir.path}/temp.pdf');

    // Check if the file exists
    if (file.existsSync()) {
      // If file exists, return the file
      return file;
    } else {
      // If file don't exists, create the file from asset and return it
      final ByteData data = await rootBundle.load('assets/name.pdf');
      final Uint8List bytes = data.buffer.asUint8List();      
      await file.writeAsBytes(bytes, flush: true);
      return file;
    }
  }

  Future<void> _save() async {
    final Directory dir = await getTemporaryDirectory();
    // Saving the file to a temporary location
    final File file = File('${dir.path}/temp.pdf');

    // Save annotations to the PDF document
    final List<int> bytes = await controller.saveDocument();
    await file.writeAsBytes(bytes, flush: true);
  }
}