Deprecate `SemanticsProperties.focusable` and `SemanticsConfiguration.isFocusable`

The SemanticsProperties.focusable and SemanticsConfiguration.isFocusable parameters were deprecated in favor of the SemanticsProperties.focused and SemanticsConfiguration.isFocused parameters.

The focused parameter is now nullable. Setting it to true or false automatically sets isFocusable to true, while setting it to null sets isFocusable to false.

The SemanticsConfiguration.isFocusable property is a boolean that indicates whether the semantics node can have input focus. SemanticsConfiguration.isFocused is a boolean that indicates if the semantics node has input focus.

This change also applies to SemanticsProperties.focusable and SemanticsProperties.focused.

We deprecated isFocusable because its functionality is covered by isFocused. The isFocused property is now stored as a tristate flag in the engine, and this change makes the framework consistent with the engine.

The SemanticsConfiguration.isFocusable property is deprecated in favor of SemanticsConfiguration.isFocused. This property is a nullable boolean; setting it to true or false automatically sets isFocusable to true, and setting it to null sets isFocusable to false.

Replace SemanticsConfiguration.isFocusable with SemanticsConfiguration.isFocused.

Code before migration:

void describeSemanticsConfiguration(SemanticsConfiguration config) {
  config.isFocusable = true;
  config.isFocused = true;
}

Code after migration:

void describeSemanticsConfiguration(SemanticsConfiguration config) {
  config.isFocused = true;
}

Code before migration:

void describeSemanticsConfiguration(SemanticsConfiguration config) {
  config.isFocusable = false;
  config.isFocused = false;
}

Code after migration:

void describeSemanticsConfiguration(SemanticsConfiguration config) {
  config.isFocused = null;
}

Landed in version: 3.37.0-0.0.pre
In stable release: 3.38

API documentation:

• SemanticsConfiguration
• SemanticsProperties
• SemanticsNode

Relevant issue:

• Issue 166092

Relevant PR:

• PR 170935