In flutter with material 3 enabled, how do I change the color of CupertinoDialogAction text globally?

Question

In a flutter app I have a ThemeData() applied to the Material app. Since setting useMaterial3: true, some colors across the app have changed. Namely, the Text color for CupertinoDialogAction in CupertinoAlertDialog has turned purple (0xFFD0BCFF).

I don't want to set the color manually for all dialogs across the app. How do I set the default color for the dialog action text? I want to keep using material 3 and not disable it.

In the theme I have tried to set colorSchemeSeed: Colors.blue but there is no change. I just can't seem to get rid of the ugly purple.

Answer 1

After digging into the source code of CupertinoDialogAction, the text color is computed by:

color: CupertinoDynamicColor.resolve(
  isDestructiveAction ? CupertinoColors.systemRed : CupertinoTheme.of(context).primaryColor,
  context,
),

To change the CupertinoTheme's primaryColor when using MaterialApp, you could either change the ThemeData.colorScheme.primary since the CupertinoTheme is derived from the MaterialTheme (check out MaterialBasedCupertinoThemeData).

theme: ThemeData(
  colorScheme: const ColorScheme.light(
    primary: Colors.blue,
  ),
  useMaterial3: true,
),

or

if you want to decouple the Cupertino styling from Material theme, you could provide a CupertinoThemeData to the ThemeData.cupertinoOverrideTheme.

theme: ThemeData(
  cupertinoOverrideTheme: const CupertinoThemeData(
    primaryColor: Colors.blue,
  ),
  useMaterial3: true,
),