Try correcting the name to an existing named parameter's name, or defining a named parameter with the name 'backgroundColor'. See https://dart.dev/diagnostics/undefined_named_parameter to learn more about this problem.

Dart Analyzer detected problems, see the logs for more information.

Try removing the variable or using it. See https://dart.dev/diagnostics/unused_local_variable to learn more about this problem.

Try breaking the line across multiple lines. See https://dart.dev/lints/lines_longer_than_80_chars to learn more about this problem.

Try replacing 'final' with 'const'. See https://dart.dev/diagnostics/prefer_const_declarations to learn more about this problem.

Try replacing 'final' with 'const'. See https://dart.dev/diagnostics/prefer_const_declarations to learn more about this problem.

Try replacing 'final' with 'const'. See https://dart.dev/diagnostics/prefer_const_declarations to learn more about this problem.

Try adding the 'const' keyword to the constructor invocation. See https://dart.dev/diagnostics/prefer_const_constructors to learn more about this problem.

Try adding the 'const' keyword to the constructor invocation. See https://dart.dev/diagnostics/prefer_const_constructors to learn more about this problem.

Try adding the 'const' keyword to the constructor invocation. See https://dart.dev/diagnostics/prefer_const_constructors to learn more about this problem.

Try adding a named parameter to the constructor. See https://dart.dev/diagnostics/use_key_in_widget_constructors to learn more about this problem.

Try adding the 'const' keyword to the constructor invocation. See https://dart.dev/diagnostics/prefer_const_constructors to learn more about this problem.