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How to change the background of the validation message in a DropdownButtonFormField widget in Flutter?

I'm using DropdownButtonFormField widget, but I can't find a way to change that color

Screenshot

I tried adding some values in inputDecoration but it didn't work, also changing some dataTheme values but I don't know if I changed the right ones.

Solution

  • You can't directly change the background color of the validation message in a DropdownButtonFormField widget. The validation message is displayed using a Text widget with a specific style defined by the Theme of your app. To change the background color of the validation message, you need to customize the Theme of your app.

    ThemeData myTheme = ThemeData(errorColor: Colors.red, // Sets the error color for validation messages inputDecorationTheme: InputDecorationTheme(errorStyle:extStyle(backgroundColor:Colors.yellow, // Set the background color for error messages), ), );

    Then Apply the custom theme to your app:

    MaterialApp( theme: myTheme, // ... your app code );

    This code defines a new theme with a custom errorColor and a custom inputDecorationTheme. The error style in the inputDecorationTheme sets the background color for the error message text, which will be applied to the validation message in your DropdownButtonFormField.

    The color of the validation message will be influenced by the errorColor you define. You might want to adjust this color as well, for consistency with the background color you choose.