MarkdownView: Use CachedNetworkImage

This is the simplest way I could find of showing a placeholder and
loading screen while the image was downloading. I'm not sure if I want
to cache the images locally.

Also, this adds lots of dependencies, which I'm not too comfortable
with.

lib/widgets/note_viewer.dart

@@ -1,3 +1,6 @@
+import 'dart:io';
+
+import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
@@ -67,7 +70,8 @@ class NoteViewer extends StatelessWidget {
                   launch(link);
                 }
               },
-              imageDirectory: note.parent.folderPath + p.separator,
+              imageBuilder: (url) => kDefaultImageBuilder(
+                  url, note.parent.folderPath + p.separator, null, null),
             ),
           ),
           // _buildFooter(context),
@@ -120,3 +124,60 @@ class NoteTitleHeader extends StatelessWidget {
     );
   }
 }
+
+//
+// Copied from flutter_markdown
+// But it uses CachedNetworkImage
+//
+typedef Widget ImageBuilder(
+    Uri uri, String imageDirectory, double width, double height);
+
+final ImageBuilder kDefaultImageBuilder = (
+  Uri uri,
+  String imageDirectory,
+  double width,
+  double height,
+) {
+  if (uri.scheme == 'http' || uri.scheme == 'https') {
+    return CachedNetworkImage(
+      imageUrl: uri.toString(),
+      width: width,
+      height: height,
+      placeholder: (context, url) => const CircularProgressIndicator(),
+      errorWidget: (context, url, error) => const Icon(Icons.error),
+    );
+  } else if (uri.scheme == 'data') {
+    return _handleDataSchemeUri(uri, width, height);
+  } else if (uri.scheme == "resource") {
+    return Image.asset(uri.path, width: width, height: height);
+  } else {
+    Uri fileUri = imageDirectory != null
+        ? Uri.parse(imageDirectory + uri.toString())
+        : uri;
+    if (fileUri.scheme == 'http' || fileUri.scheme == 'https') {
+      return CachedNetworkImage(
+        imageUrl: fileUri.toString(),
+        width: width,
+        height: height,
+        placeholder: (context, url) => const CircularProgressIndicator(),
+        errorWidget: (context, url, error) => const Icon(Icons.error),
+      );
+    } else {
+      return Image.file(File.fromUri(fileUri), width: width, height: height);
+    }
+  }
+};
+
+Widget _handleDataSchemeUri(Uri uri, final double width, final double height) {
+  final String mimeType = uri.data.mimeType;
+  if (mimeType.startsWith('image/')) {
+    return Image.memory(
+      uri.data.contentAsBytes(),
+      width: width,
+      height: height,
+    );
+  } else if (mimeType.startsWith('text/')) {
+    return Text(uri.data.contentAsString());
+  }
+  return const SizedBox();
+}

pubspec.lock

@@ -78,6 +78,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.6"
+  cached_network_image:
+    dependency: "direct main"
+    description:
+      name: cached_network_image
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0+1"
   charcode:
     dependency: transitive
     description:
@@ -85,6 +92,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.2"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   collection:
     dependency: transitive
     description:
@@ -197,6 +211,13 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_cache_manager:
+    dependency: transitive
+    description:
+      name: flutter_cache_manager
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.2"
   flutter_crashlytics:
     dependency: "direct main"
     description:
@@ -490,6 +511,27 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.6.4"
+  path_provider:
+    dependency: transitive
+    description:
+      name: path_provider
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.6.5"
+  path_provider_macos:
+    dependency: transitive
+    description:
+      name: path_provider_macos
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.4"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   pedantic:
     dependency: transitive
     description:
@@ -574,6 +616,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.6"
+  rxdart:
+    dependency: transitive
+    description:
+      name: rxdart
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.24.0"
   screenshots:
     dependency: "direct dev"
     description:
@@ -677,6 +726,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.5"
+  sqflite:
+    dependency: transitive
+    description:
+      name: sqflite
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.0"
+  sqflite_common:
+    dependency: transitive
+    description:
+      name: sqflite_common
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0+1"
   stack_trace:
     dependency: transitive
     description:

pubspec.yaml

@@ -45,6 +45,7 @@ dependencies:
   sentry: ">=3.0.0 <4.0.0"
   equatable: ^1.1.0
   purchases_flutter: ^1.1.0
+  cached_network_image: ^2.1.0+1
 
 dev_dependencies:
   flutter_launcher_icons: "^0.7.2"