How to Fix all ’const’ Warnings in Flutter/Dart

To ignore this message in a specific file only, add the following line anywhere in your dart script file.

// ignore_for_file: prefer_const_constructors

We have added this line after importing, you can add anywhere you want in the file where you want to ignore 'const' error warning.

To Fix this 'const' error in all dart files, open analysis_options.yaml file located at the project root, and add the line below linter:rules:

linter: rules: prefer_const_constructors : false

After adding this line, open the terminal add to hit the following command to apply these changes.

dart fix --apply

Output on Terminal:

PS C:\flutter_apps\testapp> dart fix --apply Computing fixes in testapp... Applying fixes... lib\main.dart prefer_const_literals_to_create_immutables • 1 fix 1 fix made in 1 file.

After this, your all warning message will disappear.

In this way, you can ignore the 'Prefer const with constant constructors' warning in specific as well as in all files in Flutter/Dart.

In this example, we are going to show you how to get the index key of a map or list array by value in Flutter or Dart. See the two examples below where we have sown how to get the key of map by value and how to get the index of List array item by value in Dart or Flutter.