Extract Widget: Update Constructor for Widget

[brianegan]

Hey hey -- Another bit of feedback regarding extract widget! Thanks so much for your help and providing the functionality, really cool to use it :)

I'd love it if the new "Extract Widget" function created a constructor that follows the normal conventions for Widget constructors:

"By convention, widget constructors only use named arguments. Named arguments can be marked as required using @required. Also by convention, the first argument is key, and the last argument is child, children, or the equivalent."

From https://docs.flutter.io/flutter/widgets/StatefulWidget-class.html

Steps to Reproduce

1. Select Widget
2. Extract Widget
3. See this constructor used: NewWidget(this.todo, this.taskKey, this.isEditing, this.noteKey);
4. Would prefer to see this constructor used: NewWidget({Key key, this.todo, this.taskKey, this.isEditing, this.noteKey}) : super(key: key);

No need to add the @required fields, as that's more of a judgement call than an automatic refactoring.

Version info

[✓] Flutter (Channel beta, v0.3.1, on Mac OS X 10.13.4 17E199, locale en-US)
    • Flutter version 0.3.1 at /Users/phillywiggins/lab/flutter
    • Framework revision 12bbaba9ae (7 days ago), 2018-04-19 23:36:15 -0700
    • Engine revision 09d05a3891
    • Dart version 2.0.0-dev.48.0.flutter-fe606f890b

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
    • Android SDK at /Users/phillywiggins/Library/Android/sdk
    • Android NDK at /Users/phillywiggins/Library/Android/sdk/ndk-bundle
    • Platform android-27, build-tools 27.0.3
    • ANDROID_HOME = /Users/phillywiggins/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.3, Build version 9E145
    • ios-deploy 1.9.2
    • CocoaPods version 1.3.1

[✓] Android Studio (version 3.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 23.2.2
    • Dart plugin version 173.4700
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] IntelliJ IDEA Community Edition (version 2018.1.2)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin version 24.0.2
    • Dart plugin version 181.4668.60

[✓] VS Code (version 1.22.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Dart Code extension version 2.11.2

[✓] Connected devices (1 available)
    • Android SDK built for x86 • emulator-5554 • android-x86 • Android 8.1.0 (API 27) (emulator)

• No issues found!

[pq]

/cc @scheglov

[scheglov]

But in the case when the refactoring creates parameters, these parameters not just @required, they are just required parameters and they are added because the code that is being extracted uses these parameters. Not providing them would make them null. Is it usually OK?

[scheglov]

https://dart-review.googlesource.com/c/sdk/+/53060

[brianegan]

@scheglov Fair point, might be best to mark em required since they are required in the initial extraction (not sure what ya did in that PR). As a heads up: You might need to ensure the document imports the foundation or meta packages in that case as well, since those modules define the @required attribute.

Thanks so much for the quick response!

[scheglov]

More improvements for Extract Widget - the widgets we are extracting are StatelessWidget and their fields are final, so the constructor can be const. Also make parameters @required.

https://dart-review.googlesource.com/c/sdk/+/54066

[lharland]

How can I extract a widget? In both vscode and Android Studio.

[scheglov]

Sorry, I don't use VS Code, cannot help you with this.

In IntelliJ base products (I use IDEA CE, but Android Studio should be the same) it is in Refactor | Extract | Flutter Widget. I gave it a keyboard shortcut for convenience, you can configure it in preferences.

[pq]

/cc @DanTup

[DanTup]

@leslieharland in VS Code the refactors can be found by clicking on the Light Bulb icon, pressing Ctrl+. (or on macOS, Cmd+.) or clicking Refactor in the context menu.