kmpdfkit_demo/lib/core/cpdf_view_ctrl.dart

import 'dart:async';

import 'package:flutter/services.dart';

import 'document/cpdf_document.dart';

///  Copyright © 2014-2023 PDF Technologies, Inc. All Rights Reserved.
///
///  THIS SOURCE CODE AND ANY ACCOMPANYING DOCUMENTATION ARE PROTECTED BY INTERNATIONAL COPYRIGHT LAW
///  AND MAY NOT BE RESOLD OR REDISTRIBUTED. USAGE IS BOUND TO THE ComPDFKit LICENSE AGREEMENT.
///  UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS SUBJECT TO CIVIL AND CRIMINAL PENALTIES.
///  This notice may not be removed from this file.

class CPDFViewCtrl {
  int _viewId = 0;

  late final MethodChannel _methodChannel;

  late final EventChannel _readerViewCallbackEventChannel;

  late final CPDFDocument document;

  // Monitor the page number currently displayed when the page slides
  var currentPageIndexStream = StreamController<int>.broadcast();
  var currentPageIndex = 0;

  // The sliding state of the current page, sliding or stopped
  var scrollStatusController = StreamController<bool>.broadcast();
  var _isScrolling = false;

  var onTapMainDocArea = StreamController<bool>.broadcast();
  var _onTapMainDocArea = false;

  StreamSubscription? _streamSubscription;

  CPDFViewCtrl(int id) {
    _viewId = id;
    document = CPDFDocument(_viewId);
    _methodChannel =
        MethodChannel('com.compdfkit.flutter.pdfviewer.settings.$_viewId');
    _readerViewCallbackEventChannel = EventChannel(
        'com.compdfkit.flutter.pdfviewer.readerview.callback.$_viewId');
    setReaderViewCallback();
  }

  /// get cpdf_reader_widget scroll Direction
  /// true : scroll vertically
  /// false : scroll horizontally
  Future<bool> isVerticalMode() async {
    return await _methodChannel.invokeMethod('isVerticalMode');
  }

  /// set scroll direction
  void setVerticalMode(bool verticalMode) async {
    await _methodChannel.invokeMethod('setVerticalMode', verticalMode);
  }

  void setDisplayPageIndex(int pageIndex) async {
    await _methodChannel.invokeMethod('setDisplayPageIndex', {
      'pageIndex' : pageIndex,
      'animation' : true
    });
  }

  void setReaderViewCallback(
      {VoidCallback? onTapMainDocArea,
      Function(int pageIndex)? onMoveToChild,
      VoidCallback? onScrolling,
      VoidCallback? onScrollEnd,
      Function(int pageIndex)? onRecordLastJumpPageNum}) {
    _streamSubscription = _readerViewCallbackEventChannel
        .receiveBroadcastStream('setReaderViewCallback')
        .listen((data) {
      Map<dynamic, dynamic> result = data;
      String eventType = result['eventType'];
      switch (eventType) {
        case 'onTapMainDocArea':
          if (onTapMainDocArea != null) {
            onTapMainDocArea();
          }
          _onTapMainDocArea = true;
          this.onTapMainDocArea.sink.add(_onTapMainDocArea);
          break;
        case 'onMoveToChild':
          int pageIndex = result['pageIndex'];
          if (onMoveToChild != null) {
            int pageIndex = result['pageIndex'];
            onMoveToChild(pageIndex);
          }
          currentPageIndex = pageIndex;
          currentPageIndexStream.sink.add(currentPageIndex);
          break;
        case 'onRecordLastJumpPageNum':
          if (onRecordLastJumpPageNum != null) {
            int pageIndex = result['pageIndex'];
            onRecordLastJumpPageNum(pageIndex);
          }
          break;
        case 'onScrollEnd':
          if (onScrollEnd != null) {
            onScrollEnd();
          }
          if (_isScrolling) {
            _isScrolling = false;
            scrollStatusController.sink.add(_isScrolling);
          }
          break;
        case 'onScrolling':
          if (onScrolling != null) {
            onScrolling();
          }
          _isScrolling = true;
          scrollStatusController.sink.add(_isScrolling);
          break;
        default:
          break;
      }
    }, cancelOnError: true);
  }

  void dispose() {
    currentPageIndexStream.close();
    scrollStatusController.close();
    _streamSubscription?.cancel();
  }
}