[Solution] The argument type 'Consumer' can't be assigned to the parameter type 'PreferredSizeWidget?'.

The error occurs because AppBar expects a widget that implements the PreferredSizeWidget interface, but Consumer<NoteModel> does not directly implement this interface. To solve this, you need to return an AppBar from within the Consumer builder method.

Here’s how you can do it:

Scaffold(
  appBar: PreferredSize(
    preferredSize: Size.fromHeight(kToolbarHeight),
    child: Consumer<NoteModel>(
      builder: (context, noteModel, child) {
        return AppBar(
          title: Text(
            'Your Title',
            style: TextStyle(
              color: noteModel.isPrivate ? Colors.red : Colors.green,
            ),
          ),
        );
      },
    ),
  ),
  body: // Your other widgets,
);

In this approach, I wrapped the Consumer<NoteModel> inside a PreferredSize widget to ensure it adheres to the PreferredSizeWidget interface required by appBar.

This should resolve the error while allowing you to update only the AppBar based on changes in your NoteModel.

Glory to ChatGPT!

Build command for deploying your flutter web app to cloudflare pages

set -x && if cd flutter; then git pull && cd .. ; else git clone https://github.com/flutter/flutter.git; (cd flutter && git fetch --tags && git checkout 3.22.3); fi && ls && flutter/bin/flutter doctor && flutter/bin/flutter clean && flutter/bin/flutter config --enable-web && cp .env.production .env && sed -i "s/VERSION_PLACEHOLDER/`git rev-parse --short HEAD`/" .env && flutter/bin/flutter build web --web-renderer html --base-href="/" --release

C# Linq:FirstOrDefault vs SingleOrDefault

In C#, both FirstOrDefault and SingleOrDefault are LINQ methods that operate on collections, but they serve different purposes:

FirstOrDefault

  • Purpose: Returns the first element in a collection that satisfies a specified condition, or the default value for the type if no such element is found.
  • Behavior:
    • If the collection contains multiple elements that satisfy the condition, it returns the first one.
    • If no elements satisfy the condition, it returns the default value (null for reference types, 0 for numeric types, etc.).
  • Use Case: When you're interested in getting the first match or a default value if none exist, and you don't care if there are multiple matches.

SingleOrDefault

  • Purpose: Returns the single element in a collection that satisfies a specified condition, or the default value for the type if no such element is found.
  • Behavior:
    • If the collection contains exactly one element that satisfies the condition, it returns that element.
    • If no elements satisfy the condition, it returns the default value.
    • If more than one element satisfies the condition, it throws an InvalidOperationException because the expectation is that there should be exactly one match.
  • Use Case: When you're expecting either one or zero matches, and multiple matches would indicate an error in your data or logic.

Summary

  • FirstOrDefault: Use when you want the first matching element or a default value, and multiple matches are acceptable.
  • SingleOrDefault: Use when you expect exactly one matching element or a default value, and multiple matches are an error.

fix TypeError: Instance of 'MappedListIterable': type 'MappedListIterable' is not a subtype of type 'FutureOr>'

--- a/lib/services/note_tag_service.dart
+++ b/lib/services/note_tag_service.dart
@@ -9,6 +9,5 @@ class NoteTagService {
   Future<Map<String, int>> getMyTagCloud() async {
     var apiResult = (await _noteTagApi.getMyTagCloud()).data;
     if (!apiResult['successful']) throw ApiException(apiResult);
-    return apiResult['data'].map((item) => {item['tag'] as String: item['count'] as int});
-  }
+    return { for (var item in apiResult['data']) item['tag'] as String : item['count'] as int };  }
 }

C# inline regular expression syntax and usage

I found this brilliant answer at Stack overflow. It is way more clearer and useful than Microsoft's official one

You can use inline modifiers as follows:

// case insensitive match
Regex MyRegex = new Regex(@"(?i)[a-z]+");  // case insensitive match

or, inverse the meaning of the modifier by adding a minus-sign:

// case sensitive match
Regex MyRegex = new Regex(@"(?-i)[a-z]+");  // case sensitive match

or, switch them on and off:

// case sensitive, then case-insensitive match
Regex MyRegex = new Regex(@"(?-i)[a-z]+(?i)[k-n]+");

Alternatively, you can use the mode-modifier span syntax using a colon : and a grouping parenthesis, which scopes the modifier to only that group:

// case sensitive, then case-insensitive match
Regex MyRegex = new Regex(@"(?-i:[a-z]+)(?i:[k-n]+)");

You can use multiple modifiers in one go like this (?is-m:text), or after another, if you find that clearer (?i)(?s)(?-m)text (I don't). When you use the on/off switching syntax, be aware that the modifier works till the next switch, or the end of the regex. Conversely, using the mode-modified spans, after the span the default behavior will apply.

Finally: the allowed modifiers in .NET are (use a minus to invert the mode):

x allow whitespace and comments
s single-line mode
m multi-line mode
i case insensitivity
n only allow explicit capture (.NET specific)