Button that can change container background color/color for flutter

Question

i'm new to flutter and i'm just learning all the basic for flutter. i came across the button widget and on pressed function and i create a simple container which have a button in it like this

here is the container

Container(

    child: Padding(
    padding: const EdgeInsets.only(top: 25.0, left: 30),
    child: Text("Item 1", style: TextStyle(
    color: Colors.lightBlueAccent,
    fontWeight: FontWeight.bold,
    fontSize: 20,
            ),
           ),
          ),

and here is the button

child: FloatingActionButton(

     onPressed(){},
    child: Text("+", style: TextStyle(
    fontSize: 20,
                 ),
                ),
    backgroundColor: Colors.lightBlue,

               ),

and i want to make the button have a function to change the container background to a certain color, like blue for example. but i cant seem to found the answer on the internet, i guess for me. is there any method which i can apply or code that i didn't know existed?

thanks in advance!!

Answer 1

Although you already got a wonderful answer from jitsm555 still Here is full-example, I hope this helps you further.

import 'package:flutter/material.dart';

void main() {
  runApp(ColorChange());
}

class ColorChange extends StatefulWidget {
  @override
  _ColorChangeState createState() => _ColorChangeState();
}

class _ColorChangeState extends State<ColorChange> {
  //Initially color is set to yellow which will be changed when button is pressed
  Color color = Colors.yellow;
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("Change Container Color"),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Container(
                width: 300,
                height: 300,
                color: color, //value of color which we will change by pressing buttons
              ),

             /* Below Row of Button when pressed will fire up 
                the setState and the state of our default color variable will 
                change according to Button which is pressed
             */
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  RaisedButton(
                    color: Colors.red,
                    child: Text("Red"),
                    onPressed: () {
                      setState(() {
                        color = Colors.red;
                      });
                    },
                  ),
                  RaisedButton(
                    color: Colors.green,
                    child: Text("Green"),
                    onPressed: () {
                      setState(() {
                        color = Colors.green;
                      });
                    },
                  ),
                  RaisedButton(
                    color: Colors.blue,
                    child: Text("Blue"),
                    onPressed: () {
                      setState(() {
                        color = Colors.blue;
                      });
                    },
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Output:

Answer 2

Declare Default Material Color

MaterialColor _color = Colors.green;

Change above color inside onPressed()

Container(
        color: _color,
        child: RaisedButton(onPressed: () {
          setState(() {
            _color = Colors.blue; // This change Container color
          });
        }),
      )