lukehutch / flutter_reactive_value Goto Github PK

From the README.md:

Now whenever counter.value changes (here using counter.value++ in the onPressed handler), the enclosing widget (here HomeView) will be scheduled for rebuilding.

(The only place you're not allowed to update counter.value is the build method of a widget, since state changes are disallowed in build methods.)

That's all there is to it!

"Upon reading this in your documentation, I am curious: wouldn't we only want the Text widget to rebuild instead of the enclosing widget (in this case, HomeView)?"

What's the best way to dispose a listener?

...
 @override
  void dispose() {
   // on dispose
    super.dispose();
  }

...
//  reactive value is in nested child
child: Builder(builder: (context) {
  final val = value.reactiveValue(context);
  return Text(val);
})

Based on the code, a new listener is registered on every rebuild and removed when the callback runs. There's is a bug when the widget is rebuilt is triggered from another ValueNotifier.

Explanation:

We have 2 ValueNotifiers: age and username
Profile widget is watching both thus resulting in 1 listener being registered for each ValueNotifier
username is modified causing ProfileWidget to rebuild, another listener is registered for each but the old listener for age is still registered. It will register an unlimited amount of listeners until its value has changed.

Hi! I'm a Flutter beginner coming from Android development. I have tried serveral state management approaches in Flutter offical document. I come from here. Most of them are not very easy to use(high learning cost), and not friendly to beginners. Thanks god, the last one in the document saves my day! Yes, this tool is soooo awesome!

Advantages:

• very easy to use, friendly to beginners
• similar state management experience for those who come from Android Compose
• easy to integrate into a viewmodel

Starred! Keep forward :D

I followed the instructions for installing flutter_reactive_value as described here.

flutter pub add flutter_reactive_value

And I added the import on my main.dart:

import 'package:flutter_reactive_value/flutter_reactive_value.dart';

That's as far as I get.

I am on dart 2.18. I tried it with all versions of this library (1.0.0 - 1.0.3). Also, I downloaded the example (the entire project folder) located here and got the same error listed below. I tried this both as a Flutter web (chrome) and a Flutter Windows app.

Flutter web (Chrome) Error:

Launching lib\main.dart on Chrome in debug mode...
main.dart:1
: Error: The getter 'mounted' isn't defined for the class 'Element'.
reactive_value_notifier.dart:30
- 'Element' is from 'package:flutter/src/widgets/framework.dart' ('../flutter/packages/flutter/lib/src/widgets/framework.dart').
framework.dart:1
Try correcting the name to the name of an existing getter, or defining a getter or field named 'mounted'.
      if (elementRef.target?.mounted ?? false) {
                             ^^^^^^^

Failed to compile application.
Exited (sigterm)

Flutter Windows Error:

Launching lib\main.dart on Windows in debug mode...
../lib/src/reactive_value_notifier.dart(30,30): error G4127D1E8: The getter 'mounted' isn't defined for the class 'Element'. [C:\workspace\flutter_reactive_value\example\build\windows\flutter\flutter_assemble.vcxproj]
C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\MSBuild\Microsoft\VC\v170\Microsoft.CppCommon.targets(247,5): error MSB8066: Custom build for 'C:\workspace\flutter_reactive_value\example\build\windows\CMakeFiles\6f135da36535027a04cd8738f00853c4\flutter_windows.dll.rule;C:\workspace\flutter_reactive_value\example\build\windows\CMakeFiles\335e6badeb606c6fb4bbef90392b261d\flutter_assemble.rule;C:\workspace\flutter_reactive_value\example\windows\flutter\CMakeLists.txt' exited with code 1. [C:\workspace\flutter_reactive_value\example\build\windows\flutter\flutter_assemble.vcxproj]
Exception: Build process failed.
Exited (sigterm)

Any ideas? I am really hoping to use the simple state management that flutter_reactive_value offers. Thanks!