Idea: Extract Widget

How it works: Highlight some widgets in a large widget build tree you’d like to start breaking down. Currently, you can easily extract these as a method in the current class using the “extract method” action. However, I often find myself creating a StatelessWidget out of this selection instead of a method and have to do that part manually. It would be very handy if you could “extract widget”.

This would allow you to create a Stateless Widget, with a constructor and fields that match the necessary params. For example, if you extracted a piece of Code, and it required a Todo with the variable name todo, the StatelessWidget would extract a final Todo todo field and a Constructor to match. The build method would return the contents of your highlighted selection.

After creating the class, it would replace your current highlighted selection with the new MyTodoWidget(todo);

Essentially, this would just be a slightly different extraction than a method.

[scheglov]

The feature is implemented. You can extract either a widget instance creation or a method that return a widget. It coverts any read local variables and fields into extract widget fields and constructor parameters.

import 'package:flutter/material.dart';

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Row(
      children: <Widget>[
        new Column(
          children: <Widget>[
            new Text('AAA'),
            new Text('BBB'),
          ],
        ),
        new Text('CCC'),
        new Text('DDD'),
      ],
    );
  }
}

import 'package:flutter/material.dart';

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Row(
      children: <Widget>[
        new NewWidget(),
        new Text('CCC'),
        new Text('DDD'),
      ],
    );
  }
}

class NewWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Column(
      children: <Widget>[
        new Text('AAA'),
        new Text('BBB'),
      ],
    );
  }
}

[bwilkerson]

@jwren