The named parameter 'title' isn't defined

user_18408976 0
Viewed 2666

I get this error for the 'title' on the second line:

The named parameter 'title' isn't defined. Try correcting the name to an existing named parameter's name, or defining a named parameter with the name 'title'.

textTheme: ThemeData.light().textTheme.copyWith(
                  title: TextStyle(
                    fontFamily: 'OpenSans',
                    fontSize: 20,
                    fontWeight: FontWeight.bold,
                  ),
dart flutter
4 Answers

You need to use titleLarge, titleMedium and titleSmall in place of title, use .copyWith() constructor.

return MaterialApp(
  title: 'MyApp',
  theme: Theme.of(context).copyWith(
    textTheme: ThemeData.light().textTheme.copyWith(
      titleSmall: Theme.of(context).textTheme.titleLarge?.copyWith(
                    fontFamily: 'OpenSans',
                    fontSize: 20,
                    fontWeight: FontWeight.bold,
                  ),
       titleLarge: Theme.of(context).textTheme.titleLarge?.copyWith(...),
       titleMedium: Theme.of(context).textTheme.titleLarge?.copyWith(...),
user_101571270

TextTheme does not include title /As you see in the below image:/ TextTheme properties

You can set theme like this

textTheme: TextTheme(
  headline1: TextStyle(fontSize: 24, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  headline2: TextStyle(fontSize: 22, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  headline3: TextStyle(fontSize: 20, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  headline4: TextStyle(fontSize: 17, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  headline5: TextStyle(fontSize: 16, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  headline6: TextStyle(fontSize: 15, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w600),
  subtitle1: TextStyle(fontSize: 14, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w500),
  subtitle2: TextStyle(fontSize: 12, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.w500),
  bodyText1: TextStyle(fontSize: 14, color: lightColors.PRIMARY_TEXT_COLOR, fontWeight: FontWeight.normal),
  bodyText2: TextStyle(fontSize: 13, color: lightColors.SECONDARY_TEXT_COLOR, fontWeight: FontWeight.normal),
  button: TextStyle(fontSize: 15, color: lightColors.GRAY_COLOR_100)
),

And use it in your App

Text("Text", style: Theme.of(context).textTheme.subtitle1!.copyWith())
user_184142860

With the latest version of Flutter, some theme identifiers changed.

display4 => headline1;
display3 => headline2;
display2 => headline3;
display1 => headline4;
headline => headline5;
title    => headline6; // so use headline6 instead of title
subhead  => subtitle1;
subtitle => subtitle2;
body2    => bodyText1; 
body     => bodyText2;

So you can define your Theme like this:

textTheme: ThemeData.light().textTheme.copyWith(
                  headline6: TextStyle(
                    fontFamily: 'OpenSans',
                    fontSize: 20,
                    fontWeight: FontWeight.bold,
                  ),

and then use it e.g. like this:

Text(
    'my text',
    style: Theme.of(context).textTheme.headline6,
   ),
user_123201090
user_141114270
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