TF-105 Create HtmlContentViewer widget

core/lib/core.dart

@@ -38,6 +38,7 @@ export 'presentation/views/context_menu/simple_context_menu_action_builder.dart'
 export 'presentation/views/dialog/loading_dialog_builder.dart';
 export 'presentation/views/dialog/downloading_file_dialog_builder.dart';
 export 'presentation/views/background/background_widget_builder.dart';
+export 'presentation/views/html_viewer/html_content_viewer_widget.dart';
 
 // Resources
 export 'presentation/resources/assets_paths.dart';

core/lib/presentation/views/html_viewer/html_content_viewer_widget.dart

@@ -0,0 +1,171 @@
+import 'package:core/core.dart';
+import 'package:core/presentation/utils/html_transformer/html_transform.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
+
+class _HtmlGenerationArguments {
+  final String message;
+  final bool blockExternalImages;
+
+  const _HtmlGenerationArguments(
+    this.message,
+    this.blockExternalImages,
+  );
+}
+
+class _HtmlGenerationResult {
+  final String? html;
+  final String? errorDetails;
+
+  const _HtmlGenerationResult.success(this.html) : errorDetails = null;
+
+  const _HtmlGenerationResult.error(this.errorDetails) : this.html = null;
+}
+
+class HtmlContentViewer extends StatefulWidget {
+
+  final String message;
+  final bool blockExternalImages;
+
+  /// Is notified about any errors that might occur
+  final void Function(Object? exception, StackTrace? stackTrace)? onError;
+
+  /// Register this callback if you want a reference to the [InAppWebViewController].
+  final void Function(InAppWebViewController controller)? onWebViewCreated;
+
+  const HtmlContentViewer({
+    Key? key,
+    required this.message,
+    this.blockExternalImages = false,
+    this.onError,
+    this.onWebViewCreated,
+  }) : super(key: key);
+
+  @override
+  State<StatefulWidget> createState() => _HtmlContentViewState();
+}
+
+class _HtmlContentViewState extends State<HtmlContentViewer> {
+
+  String? _htmlData;
+  bool? _wereExternalImagesBlocked;
+  bool _isGenerating = false;
+  double? _webViewContentHeight;
+
+  @override
+  void initState() {
+    _generateHtml(widget.blockExternalImages);
+    super.initState();
+  }
+
+  void _generateHtml(bool blockExternalImages) async {
+    _wereExternalImagesBlocked = blockExternalImages;
+    _isGenerating = true;
+    final args = _HtmlGenerationArguments(
+      widget.message,
+      blockExternalImages,
+    );
+    final result = await compute(_generateHtmlImpl, args);
+    _htmlData = result.html;
+    if (_htmlData == null) {
+      final onError = widget.onError;
+      if (onError != null) {
+        onError(result.errorDetails, null);
+      }
+    }
+    if (mounted) {
+      setState(() {
+        _isGenerating = false;
+      });
+    }
+  }
+
+  static _HtmlGenerationResult _generateHtmlImpl(_HtmlGenerationArguments args) {
+    try {
+      final htmlTransform = HtmlTransform(args.message);
+      final html = htmlTransform.transformToHtml(
+        blockExternalImages: args.blockExternalImages,
+      );
+      return _HtmlGenerationResult.success(html);
+    } catch (e, s) {
+      String errorDetails = e.toString() + '\n\n' + s.toString();
+      return _HtmlGenerationResult.error(errorDetails);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (_isGenerating) {
+      return Padding(
+        padding: const EdgeInsets.all(16.0),
+        child: Center(
+          child: SizedBox(
+            width: 30,
+            height: 30,
+            child: CircularProgressIndicator(color: AppColor.primaryColor)),
+        ),
+      );
+    }
+    if (widget.blockExternalImages != _wereExternalImagesBlocked) {
+      _generateHtml(widget.blockExternalImages);
+    }
+
+    final size = MediaQuery.of(context).size;
+    return SizedBox(
+      height: _webViewContentHeight ?? size.height,
+      width: size.width,
+      child: Padding(
+        padding: EdgeInsets.only(top: 16),
+        child: _buildWebView(),
+      ),
+    );
+  }
+
+  Widget _buildWebView() {
+    if (_htmlData == null) {
+      return Container();
+    }
+
+    return InAppWebView(
+      key: ValueKey(_htmlData),
+      initialData: InAppWebViewInitialData(data: _htmlData!),
+      initialOptions: InAppWebViewGroupOptions(
+        crossPlatform: InAppWebViewOptions(
+          useShouldOverrideUrlLoading: true,
+          verticalScrollBarEnabled: false,
+        ),
+        android: AndroidInAppWebViewOptions(
+          useHybridComposition: true,
+        ),
+        ios: IOSInAppWebViewOptions(
+          allowsInlineMediaPlayback: true,
+          enableViewportScale: true,
+        )
+      ),
+      onWebViewCreated: widget.onWebViewCreated,
+      onLoadStop: (controller, uri) async {
+        var scrollHeight = (await controller.evaluateJavascript(source: 'document.body.scrollHeight'));
+        if (scrollHeight != null) {
+          final scrollWidth = (await controller.evaluateJavascript(source: 'document.body.scrollWidth'));
+          final size = MediaQuery.of(context).size;
+          if (scrollWidth > size.width) {
+            var scale = (size.width / scrollWidth);
+            if (scale < 0.2) {
+              scale = 0.2;
+            }
+            await controller.zoomBy(zoomFactor: scale, iosAnimated: true);
+            scrollHeight = (scrollHeight * scale).ceil();
+          }
+          setState(() {
+            _webViewContentHeight = double.tryParse('${scrollHeight + 10.0}');
+          });
+        }
+      },
+      gestureRecognizers: {
+        Factory<LongPressGestureRecognizer>(() => LongPressGestureRecognizer()),
+      },
+    );
+  }
+}

core/pubspec.yaml

@@ -59,6 +59,13 @@ dependencies:
   # getwidget
   getwidget: 2.0.4
 
+  # Used to fix bugs in the official version of flutter_inappwebview: https://githubmemory.com/repo/pichillilorenzo/flutter_inappwebview/issues/873
+  # flutter_inappwebview
+  flutter_inappwebview:
+    git:
+      url: git://github.com/robert-virkus/flutter_inappwebview.git
+      ref: master
+
 dev_dependencies:
   flutter_test:
     sdk: flutter