Building and Using a Flutter DevTools Extension with Back4app

introduction flutter devtools is a powerful suite for debugging, inspecting, and profiling flutter apps with the dart & flutter devtools extension framework, developers can create custom extensions to enhance their debugging and development workflows these extensions can be built as flutter web apps and seamlessly integrated into the devtools suite in this tutorial, we will explore how to create a flutter devtools extension, integrate it with a flutter app that uses back4app for backend services, and debug the application using the custom extension this will help you build tailored developer tools that can streamline your development process and provide deeper insights into your app's behavior prerequisites to complete this tutorial, you will need a back4app account sign up for a free account at back4app com https //www back4app com a flutter development environment set up on your local machine follow the flutter installation guide https //flutter dev/docs/get started/install if you haven't set it up yet basic knowledge of dart, flutter widgets, and using flutter devtools step 1 – setting up your back4app backend create a back4app project log in to your back4app account https //www back4app com/ and create a new project create parse classes for this tutorial, create a parse class named themesettings to store theme configuration data for your flutter app themename (string) the name of the theme primarycolor (string) the primary color of the theme accentcolor (string) the accent color of the theme populate the class with sample data add several records to the themesettings class to simulate theme configurations that your flutter app will use get your back4app credentials navigate to your project settings to retrieve your application id and client key, which you’ll need to connect your flutter app to back4app step 2 – creating the flutter devtools extension create a new flutter project open your terminal or command prompt and run flutter create theme builder extension set up the extension directory navigate to your project root directory and create a new directory for your devtools extension mkdir devtools extension inside this directory, create a config yaml file to store metadata required by devtools package name theme builder extension version 1 0 0 issue tracker https //github com/yourusername/theme builder extension/issues material icon assets/icon png add dependencies open pubspec yaml and add the following dependencies dependencies flutter sdk flutter devtools extensions latest version devtools app shared latest version run flutter pub get to install these dependencies creating the devtools extension in lib/main dart , replace the default content with the following code to wrap your flutter web app in a devtoolsextension widget import 'package\ flutter/material dart'; import 'package\ devtools extensions/devtools extensions dart'; import 'package\ devtools app shared/devtools app shared dart'; void main() { runapp(devtoolsextension(child themebuilderapp())); } class themebuilderapp extends statelesswidget { @override widget build(buildcontext context) { return scaffold( appbar appbar(title text('theme builder')), body center( child elevatedbutton( onpressed () { // your extension logic here }, child text('generate theme'), ), ), ); } } this wraps your app in the devtoolsextension widget, which handles theming and integration with the devtools suite adding devtools integrations modify your app to integrate devtools specific features, such as using the devtoolsbutton instead of a regular elevatedbutton class themebuilderapp extends statelesswidget { @override widget build(buildcontext context) { return scaffold( appbar appbar(title text('theme builder')), body center( child devtoolsbutton( onpressed () { // your extension logic here }, child text('generate theme'), ), ), ); } } this change ensures your extension’s ui blends seamlessly with the rest of the devtools suite step 3 – integrating with back4app initialize parse in your extension since this extension will interact with back4app, initialize parse in your extension import 'package\ parse server sdk flutter/parse server sdk flutter dart'; void main() async { widgetsflutterbinding ensureinitialized(); const keyapplicationid = 'your back4app app id'; const keyclientkey = 'your back4app client key'; const keyparseserverurl = 'https //parseapi back4app com'; await parse() initialize(keyapplicationid, keyparseserverurl, clientkey keyclientkey, autosendsessionid true); runapp(devtoolsextension(child themebuilderapp())); } fetch and use theme data use the data from back4app in your extension to generate and apply themes class themebuilderapp extends statelesswidget { @override widget build(buildcontext context) { return scaffold( appbar appbar(title text('theme builder')), body futurebuilder\<list\<parseobject>>( future fetchthemes(), builder (context, snapshot) { if (!snapshot hasdata) { return circularprogressindicator(); } final themes = snapshot data!; return listview\ builder( itemcount themes length, itembuilder (context, index) { final theme = themes\[index]; return listtile( title text(theme get\<string>('themename') ?? 'no name'), subtitle text('primary color ${theme get\<string>('primarycolor')}'), ontap () { // apply theme logic }, ); }, ); }, ), ); } future\<list\<parseobject>> fetchthemes() async { final query = querybuilder\<parseobject>(parseobject('themesettings')); final response = await query query(); if (response success && response results != null) { return response results as list\<parseobject>; } else { throw exception('failed to load themes'); } } } this code fetches theme settings from back4app and displays them in a list selecting a theme could trigger additional logic to apply it step 4 – testing your extension in a simulated environment run the extension in a simulated environment to test your extension without compiling it every time, use the simulated devtools environment flutter run d chrome dart define=use simulated environment=true simulate the connected app start another flutter app that your extension will connect to copy and paste the connected app’s vm service uri and dtd service uri into the simulated environment step 5 – building and publishing the extension build the extension once you are satisfied with your extension, build it for production flutter pub get flutter build web output=devtools extension/build validate the extension use the devtools validation command to ensure your extension is correctly configured dart run devtools extensions validate publish the extension publish your extension to pub dev so other developers can use it flutter pub publish conclusion in this tutorial, you learned how to create a flutter devtools extension, integrate it with back4app for backend services, and test it in a simulated environment by extending devtools, you can build custom tools that enhance your productivity and offer new insights into your app’s behavior once your extension is ready, publishing it to pub dev allows other developers to benefit from your work for more information on using flutter with back4app, check out the back4app documentation https //www back4app com/docs and the flutter devtools documentation https //flutter dev/docs/development/tools/devtools/overview happy coding!