live_cell_widgets 0.12.1

Provides wrappers over Flutter widgets which allow the properties of the widgets to be controlled by ValueCell's

This package provides wrappers over Flutter widgets which allow their properties to be accessed and controlled by ValueCell's, a ValueNotifier-like interface. If you're new to Live Cells see the live_cells package for a getting started guide, documentation and examples.

Features

• This library allows you to write this:

  final content = MutableCell('');
  
  @override
  Widget build(BuildContext context) {
    return Column([
      CellText(data: content),
      ElevatedButton(
        child: Text('Say Hi!'),
        onPressed: () => content.value = 'Hi!'
      )
    ]);
  }
  

  Instead of this:

  final content = ValueNotifier('');
  
  @override
  void dispose() {
    content.dispose();
    super.dispose();
  }
  
  @override
  Widget build(BuildContext context) {
    return Column([
      ValueListenableBuilder(
        valueListenable: content,
        builder: (context, content, _) => Text(content)
      ),
      ElevatedButton(
        child: Text('Say Hi!'),
        onPressed: () => content.value = 'Hi!'
     )
   ]);
  }
  

• Data can flow in both ways, which allows you to write this:

  final switchState = MutableCell(true);
  
  @override
  Widget build(BuildContext context) {
    return Column([
      CellSwitch(
        value: switchState
      )
    ]);
  }
  

  instead of this:

  final switchState = ValueNotifier(true);
  
  @override
  void dispose() {
    switchState.dispose();
    super.dispose();
  }
  
  @override
  Widget build(BuildContext context) {
    return Column([
      ValueListenableBuilder(
        valueListenable: switchState,
        builder: (context, value, _) => Switch(
            value: value,
            onChanged: (value) => switchState.value = value
        )
      )
    ]);
  }
  

• Much less verbose than setting up (and disposing) ValueNotifier's and ValueListenableBuilder's.

• Eliminates the need for controller objects (still a work in progress).

• ValueCell's can be defined as an expression of other ValueCell's allowing for a declarative style of programming. ValueNotifiers cannot.

• ValueCell's do not have to be disposed manually.

Usage

The provided wrapper classes are named the same as their corresponding Flutter widget classes but prefixed with Cell, e.g. CellText is the wrapper for Flutter's Text, CellSwitch is the wrapper for Flutter's Switch.

Each wrapper class provides a constructor which accepts the same arguments (with a few exceptions) as the constructor of the equivalent Flutter widget, but instead of taking raw values each argument takes a ValueCell. The only exception is the key argument which is not a ValueCell.

Every wrapper class also provides a bind method which creates a copy of the widget but with different values (ValueCell's) for some of the properties.

For example, the following:

final text = CellText(data: 'hello'.cell) // Initialize with a const 'hello'
  .bind(data: content)    // Bind the data property to the cell `content`
  .bind(style: textStyle); // Bind the style property to the cell `textStyle`

is equivalent to:

final text = CellText(
  data: content,
  style: textStyle
);

Additional information

• For the full list of the wrapper classes provided, check this package's API documentation.
• For an introduction to ValueCell's and their capabilities, visit the live_cells package.
• If you'd like a wrapper class for a specific widget, open an issue on the package's Github repository.