defaultStyleOf abstract method

Returns a ButtonStyle that's based primarily on the Theme's ThemeData.textTheme and ThemeData.colorScheme, but has most values filled out (non-null).

The returned style can be overridden by the style parameter and by the style returned by themeStyleOf that some button-specific themes like TextButtonTheme or ElevatedButtonTheme override. For example the default style of the TextButton subclass can be overridden with its TextButton.style constructor parameter, or with a TextButtonTheme.

Concrete button subclasses should return a ButtonStyle with as many non-null properties as possible, where all of the non-null WidgetStateProperty properties resolve to non-null values.

Properties that can be null

Some properties, like ButtonStyle.fixedSize would override other values in the same ButtonStyle if set, so they are allowed to be null. Here is a summary of properties that are allowed to be null when returned in the ButtonStyle returned by this function, an why:

• ButtonStyle.fixedSize because it would override other values in the same ButtonStyle, like ButtonStyle.maximumSize.
• ButtonStyle.side because null is a valid value for a button that has no side. OutlinedButton returns a non-null default for this, however.
• ButtonStyle.backgroundBuilder and ButtonStyle.foregroundBuilder because they would override the ButtonStyle.foregroundColor and ButtonStyle.backgroundColor of the same ButtonStyle.

See also:

• themeStyleOf, returns the ButtonStyle of this button's component theme.