how to change button back color in flutter code example

Example 1: raised button background color doesn't changeflutter

RaisedButton(
              onPressed: null,
              child: Text('Get in'), // change it to sign-in
              color: Colors.blue,
              disabledColor: Colors.blue,//add this to your code
            )

Example 2: raisedbutton background color

List<bool> _list = [true, false, true, false];

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(title: Text("Title")),
    body: ListView(children: _buildButtons()),
  );
}

List<Widget> _buildButtons() {
  List<Widget> listButtons = List.generate(_list.length, (i) {
    return RaisedButton(
      color: _list[i] ? Colors.green : Colors.red,
      onPressed: () {
        setState(() {
          _list[i] = !_list[i];
        });
      },
      child: Text("Button #${i}"),
    );
  });
  return listButtons;
}