ui_playground_annotations 0.0.6

Annotations package for UI Playground code generation with build_runner.

ui_playground_annotations

Purpose

A pure Dart package containing annotations for the UI Playground code generation system.

Other packages

This packages is part of an ecosystem of packages that work together to create an ui playground for testing and showcasing UI components.

• ui_playground_generator - The build_runner code generator that creates playground items from annotations
• ui_playground - The Flutter UI package that provides the playground UI widget

Available Annotations

@UiPlaygroundComponent

Marks a widget class for playground code generation.

import 'package:ui_playground/ui_playground.dart';

@UiPlaygroundComponent(
  title: 'My Button',           // Optional: Display name in playground
  excludeParams: ['onTap'],     // Optional: Parameters to exclude from inputs
)
class MyButton extends StatelessWidget {
  // ...
}

Parameters

Parameter	Type	Default	Description
title	String?	Class name	Display title for the component in the playground
excludeParams	List<String>	[]	Constructor parameters to exclude from input generation
customInputs	List<Type>	[]	Custom input classes for this component

Custom Inputs

Use customInputs to provide custom input widgets for types that aren't supported by default:

@UiPlaygroundComponent(
  title: 'My Widget',
  customInputs: [
    MyEdgeInsetsInput,  // extends UiPlaygroundInputItem<EdgeInsets>
  ],
)
class MyWidget extends StatelessWidget {
  final EdgeInsets padding;  // Will use MyEdgeInsetsInput
  // ...
}

@UiPlaygroundComponents

Marks a class as the aggregation point for all generated playground items.

import 'package:ui_playground/ui_playground.dart';
import 'package:my_app/ui_playground/components.ui_playground.dart';

@UiPlaygroundComponents()
class AppComponents {
  static List<UiPlaygroundItem> get items => GeneratedUiPlaygroundComponents.items;
}

The generator will:

1. Scan all files for @UiPlaygroundComponent annotations
2. Generate a complete standalone file with all imports and playground items
3. Create GeneratedUiPlaygroundComponents.items containing all components

Parameters

Parameter	Type	Default	Description
extraComponents	List<UiPlaygroundComponentConfig>	[]	External components to include (for widgets you can't annotate)
extraComponentsOnly	bool	false	If true, skip scanning for @UiPlaygroundComponent and only use extraComponents list
customInputs	List<Type>	[]	Global custom input classes that apply to all components

Global Custom Inputs

Use customInputs on @UiPlaygroundComponents to define custom inputs that apply globally to all components. The generator automatically extracts the target type from the generic parameter:

// Define your custom input class
class MyEdgeInsetsInput extends UiPlaygroundInputItem<EdgeInsets> {
  MyEdgeInsetsInput(super.label, {super.initialValue, super.extraInfo});

  @override
  Widget build(BuildContext context) {
    // Build your custom input widget
  }
}

// Register it globally
@UiPlaygroundComponents(
  customInputs: [
    MyEdgeInsetsInput,  // All EdgeInsets parameters will use this
  ],
)
class AppComponents {
  static List<UiPlaygroundItem> get items => GeneratedUiPlaygroundComponents.items;
}

Per-component customInputs (on @UiPlaygroundComponent or UiPlaygroundComponentConfig) take precedence over global custom inputs.

UiPlaygroundComponentConfig

Configuration for external widgets (from packages you cannot modify).

@UiPlaygroundComponents(
  extraComponents: [
    UiPlaygroundComponentConfig(
      ExternalButton,
      title: 'External Button',      // Optional: Display name
      excludeParams: ['onTap'],      // Optional: Parameters to exclude
      customInputs: [                // Optional: Custom input classes
        MyEdgeInsetsInput,
      ],
    ),
  ],
)
class AppComponents { ... }

Creating Custom Input Classes

Custom input classes must extend UiPlaygroundInputItem<T> where T is the type you want to handle:

class MyEdgeInsetsInput extends UiPlaygroundInputItem<EdgeInsets> {
  MyEdgeInsetsInput(
    super.label, {
    super.initialValue,
    super.extraInfo,
  });

  @override
  Widget build(BuildContext context) {
    // Build your custom input widget
    return MyEdgeInsetsEditor(
      value: value,
      onChanged: updateState,
    );
  }
}

The generator will:

1. Find the generic type T from UiPlaygroundInputItem<T>
2. Use your custom input for all parameters of type T

Using extraComponentsOnly

When your playground only uses external components:

@UiPlaygroundComponents(
  extraComponentsOnly: true,  // Skip scanning for @UiPlaygroundComponent
  extraComponents: [
    UiPlaygroundComponentConfig(ExternalButton),
    UiPlaygroundComponentConfig(ExternalCard),
  ],
)
class AppComponents {
  static List<UiPlaygroundItem> get items => GeneratedUiPlaygroundComponents.items;
}

Usage

This package is typically not used directly. Instead, use ui_playground which re-exports these annotations:

// Recommended: Import from ui_playground
import 'package:ui_playground/ui_playground.dart';

// Also works: Import directly
import 'package:ui_playground_annotations/ui_playground_annotations.dart';

Package Structure

ui_playground_annotations/
├── lib/
│   ├── ui_playground_annotations.dart  # Library export
│   └── src/
│       ├── component.dart              # @UiPlaygroundComponent annotation
│       └── components.dart             # @UiPlaygroundComponents annotation
└── pubspec.yaml