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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!
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
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.
--- 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 }; }
+ }