Contents

Rename MaterialState to WidgetState

Contents

Summary

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MaterialState, and its related APIs, have been moved out of the Material library and renamed to WidgetState.

Background

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Previously, MaterialState provided logic for handling multiple different states a widget could have, like "hovered", "focused", and "disabled". Because this functionality is useful outside the Material library, namely for the base Widgets layer and Cupertino, it was decided to move it outside of Material. As part of the move, and to avoid future confusion, the different MaterialState classes have been renamed to WidgetState. The behavior of the two are the same.

BeforeNow
MaterialStateWidgetState
MaterialStatePropertyResolverWidgetStatePropertyResolver
MaterialStateColorWidgetStateColor
MaterialStateMouseCursorWidgetStateColorMouseCursor
MaterialStateBorderSideWidgetStateBorderSide
MaterialStateOutlinedBorderWidgetStateOutlinedBorder
MaterialStateTextStyleWidgetStateTextStyle
MaterialStatePropertyWidgetStateProperty
MaterialStatePropertyAllWidgetStatePropertyAll
MaterialStatesControllerWidgetStatesController

The classes MaterialStateOutlineInputBorder and MaterialStateUnderlineInputBorder were left in the Material library with no WidgetState equivalent, as they are specific to Material design.

Migration guide

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A Flutter fix is available to help migrate the MaterialState classes to WidgetState.

To migrate, replace MaterialState with WidgetState.

Code before migration:

dart
MaterialState selected = MaterialState.selected;

final MaterialStateProperty<Color> backgroundColor;

class _MouseCursor extends MaterialStateMouseCursor{
  const _MouseCursor(this.resolveCallback);

  final MaterialPropertyResolver<MouseCursor?> resolveCallback;

  @override
  MouseCursor resolve(Set<MaterialState> states) => resolveCallback(states) ?? MouseCursor.uncontrolled;
}

BorderSide side = MaterialStateBorderSide.resolveWith((Set<MaterialState> states) {
  if (states.contains(MaterialState.selected)) {
    return const BorderSide(color: Colors.red);
  }
  return null;
});

Code after migration:

dart
WidgetState selected = WidgetState.selected;

final WidgetStateProperty<Color> backgroundColor;

class _MouseCursor extends WidgetStateMouseCursor{
  const _MouseCursor(this.resolveCallback);

  final WidgetPropertyResolver<MouseCursor?> resolveCallback;

  @override
  MouseCursor resolve(Set<WidgetState> states) => resolveCallback(states) ?? MouseCursor.uncontrolled;
}

BorderSide side = WidgetStateBorderSide.resolveWith((Set<WidgetState> states) {
  if (states.contains(WidgetState.selected)) {
    return const BorderSide(color: Colors.red);
  }
  return null;
});

Timeline

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Landed in version: 3.21.0-11.0.pre
In stable release: 3.22.0

References

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Relevant issues:

Relevant PRs:

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