Passing String to widget-CodePudding

Total newbie here but I can't get around this. I want a reusable widget that takes a String title in its constructor and then uses it in the build's widget:

import 'package:flutter/material.dart';

class TemperatureInputDecoration extends StatelessWidget {
  const TemperatureInputDecoration({Key? key, required this.title})
    : super(key: key);
  final String title;

  @override
  Widget build(BuildContext context) {
    return const InputDecorator(
      decoration: InputDecoration(
        labelText: title,
        focusColor: Colors.orangeAccent,
      ),
    );
  }
}

I get an error on the line 'labelText: title' saying 'Invalid constant value'. I've tried widget.title, creating a getter for super.widget and using a Stateful widget but no go.

I've seen this page but none of it worked for me. Maybe it has something to do with InputDecoration not being a widget? Any help appreciated.

CodePudding user response：

InputDecoration is not a widget, as defined by the class,

import 'package:flutter/material.dart';

class TemperatureInputDecoration extends StatelessWidget {
  const TemperatureInputDecoration({Key? key, required this.title})
    : super(key: key);
  final String title;

  @override
  Widget build(BuildContext context) {
    return const Text(
      title,
      style: TextStyle(color: Colors.red)
    );
  }
}

this will work just fine

CodePudding user response：

Turns out it was simple, just extend InputDecoration rather than StatefulWidget:

import 'package:flutter/material.dart';

class TemperatureInputDecoration extends InputDecoration {
  const TemperatureInputDecoration({required this.text, required this.color});

  final String text;
  final Color color;

  @override
  String get labelText => text;

  @override
  Color get focusColor => color;
}

Now I can just instantiate the Decoration where I need it, passing text and color in from above rather than inline.

CodePudding user response：

Try this:

class TemperatureInputDecoration extends StatefulWidget {
  TemperatureInputDecoration (this.uid);
  final uid;
  @override
  TemperatureInputDecorationstate  createState() => TemperatureInputDecorationstate  (this.uid);
}

class TemperatureInputDecorationstate    extends State<TemperatureInputDecoration > {
      TemperatureInputDecorationstate (this.uid);
  var uid;
//you can use uid inside widget.....
}

and to reuse variable:

TemperatureInputDecoration('set here uid value');