View a PDF document in Flutter

There are 2 different ways to use Apryse Flutter API:

• Present a document via a plugin.
• Show an Apryse document view via a Widget.

You must choose either the widget or plugin, and use it for all APIs. Mixing widget and plugin APIs will not function correctly. Whether you choose the widget or plugin is personal preference.

If you pick the Android widget, you will need to add padding for operating system intrusions like the status bar at the top of the device. One way is to set the enabled system UI, and then wrap the widget in a SafeArea or use an AppBar:

// If using Flutter v2.3.0-17.0.pre or earlier.
SystemChrome.setEnabledSystemUIOverlays(
  SystemUiOverlay.values
);
// If using later Flutter versions.
SystemChrome.setEnabledSystemUIMode(
  SystemUiMode.edgeToEdge,
);

// If using SafeArea:
return SafeArea (
  child: DocumentView(
    onCreated: _onDocumentViewCreated,
  ));

// If using AppBar:
return Scaffold(
  appBar: AppBar( toolbarHeight: 0 ),
  body: DocumentView(
    onCreated: _onDocumentViewCreated,
  ));

If you want to use local files, add the following dependency to myapp/pubspec.yaml:

permission_handler: ^8.1.1

Replace lib/main.dart with what is shown here:

import 'dart:async';
import 'dart:io' show Platform;

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:pdftron_flutter/pdftron_flutter.dart';
// If you are using local files, add the permission_handler
// dependency to pubspec.yaml and uncomment the line below.
// import 'package:permission_handler/permission_handler.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Viewer(),
    );
  }
}

class Viewer extends StatefulWidget {
  @override
  _ViewerState createState() => _ViewerState();
}

class _ViewerState extends State<Viewer> {
  String _version = 'Unknown';
  String _document =
      "https://pdftron.s3.amazonaws.com/downloads/pl/PDFTRON_mobile_about.pdf";
  bool _showViewer = true;

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

    showViewer();

    // If you are using local files:
    // * Remove the above line `showViewer();`.
    // * Change the _document field to your local filepath.
    // * Uncomment the section below, including launchWithPermission().
    // if (Platform.isIOS) {
      // showViewer(); // Permission not required for iOS.
    // } else {
      // launchWithPermission(); // Permission required for Android.
    // }
  }

  // Uncomment this if you are using local files:
  // Future<void> launchWithPermission() async {
  //  PermissionStatus permission = await Permission.storage.request();
  //  if (permission.isGranted) {
  //    showViewer();
  //  }
  // }

  // Platform messages are asynchronous, so initialize in an async method.
  Future<void> initPlatformState() async {
    String version;
    // Platform messages may fail, so use a try/catch PlatformException.
    try {
      // Initializes the Apryse SDK, it must be called before you can use 
      // any functionality.
      PdftronFlutter.initialize("your_pdftron_license_key");

      version = await PdftronFlutter.version;
    } on PlatformException {
      version = 'Failed to get platform version.';
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _version = version;
    });
  }

  void showViewer() async {
    // Opening without a config file will have all functionality enabled.
    // await PdftronFlutter.openDocument(_document);

    var config = Config();
    // How to disable functionality:
    //      config.disabledElements = [Buttons.shareButton, Buttons.searchButton];
    //      config.disabledTools = [Tools.annotationCreateLine, Tools.annotationCreateRectangle];
    // Other viewer configurations:
    //      config.multiTabEnabled = true;
    //      config.customHeaders = {'headerName': 'headerValue'};

    // An event listener for document loading.
    var documentLoadedCancel = startDocumentLoadedListener((filePath) {
      print("document loaded: $filePath");
    });

    await PdftronFlutter.openDocument(_document, config: config);

    try {
      // The imported command is in XFDF format and tells whether to add, 
      // modify or delete annotations in the current document.
      PdftronFlutter.importAnnotationCommand(
          "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
              "    <xfdf xmlns=\"http://ns.adobe.com/xfdf/\" xml:space=\"preserve\">\n" +
              "      <add>\n" +
              "        <square style=\"solid\" width=\"5\" color=\"#E44234\" opacity=\"1\" creationdate=\"D:20200619203211Z\" flags=\"print\" date=\"D:20200619203211Z\" name=\"c684da06-12d2-4ccd-9361-0a1bf2e089e3\" page=\"1\" rect=\"113.312,277.056,235.43,350.173\" title=\"\" />\n" +
              "      </add>\n" +
              "      <modify />\n" +
              "      <delete />\n" +
              "      <pdf-info import-version=\"3\" version=\"2\" xmlns=\"http://www.pdftron.com/pdfinfo\" />\n" +
              "    </xfdf>");
    } on PlatformException catch (e) {
      print("Failed to importAnnotationCommand '${e.message}'.");
    }

    try {
      PdftronFlutter.importBookmarkJson('{"0":"Page 1"}');
    } on PlatformException catch (e) {
      print("Failed to importBookmarkJson '${e.message}'.");
    }

    // An event listener for when local annotation changes are committed to the document.
    // xfdfCommand is the XFDF Command of the annotation that was last changed.
    var annotCancel = startExportAnnotationCommandListener((xfdfCommand) {
      String command = xfdfCommand;
      print("flutter xfdfCommand:\n");
      // Dart limits how many characters are printed onto the console. 
      // The code below ensures that all of the XFDF command is printed.
      if (command.length > 1024) {
        int start = 0;
        int end = 1023;
        while (end < command.length) {
          print(command.substring(start, end) + "\n");
          start += 1024;
          end += 1024;
        }
        print(command.substring(start));
      } else {
        print("flutter xfdfCommand:\n $command");
      }
    });

    // An event listener for when local bookmark changes are committed to
    // the document. bookmarkJson is the JSON string containing all the 
    // bookmarks that exist when the change was made.
    var bookmarkCancel = startExportBookmarkListener((bookmarkJson) {
      print("flutter bookmark: $bookmarkJson");
    });

    var path = await PdftronFlutter.saveDocument();
    print("flutter save: $path");

    // To cancel event:
    // annotCancel();
    // bookmarkCancel();
    // documentLoadedCancel();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        width: double.infinity,
        height: double.infinity,
        child:
            // Uncomment this to use Widget version of the viewer:
            // _showViewer
            // ? DocumentView(
            //     onCreated: _onDocumentViewCreated,
            //   ):
            Container(),
      ),
    );
  }

  // This function is used to control the DocumentView widget after it
  // has been created. The widget will not work without a void 
  // Function(DocumentViewController controller) being passed to it.
  void _onDocumentViewCreated(DocumentViewController controller) async {
    Config config = new Config();

    var leadingNavCancel = startLeadingNavButtonPressedListener(() {
      // Uncomment this to quit viewer when leading navigation button is pressed:
      // this.setState(() {
      //   _showViewer = !_showViewer;
      // });

      // Show a dialog when leading navigation button is pressed.
      _showMyDialog();
    });

    controller.openDocument(_document, config: config);
  }

  Future<void> _showMyDialog() async {
    print('hello');
    return showDialog<void>(
      context: context,
      barrierDismissible: false, // User must tap button!
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('AlertDialog'),
          content: SingleChildScrollView(
            child: Text('Leading navigation button has been pressed.'),
          ),
          actions: <Widget>[
            TextButton(
              child: Text('OK'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }
}