title: How can I align a form in the center using Flutter?
body: <p>I have a program written in Flutter and I would like to center the form in the middle of the screen but I can't get it.
  I tried to use Align and I don't think I am using it correctly!
  Someone can help me? Thanks</p>
  
  <pre><code>class _Defini extends State&lt;Definicoes&gt; {
  
    GlobalKey&lt;FormState&gt; _formkey = GlobalKey&lt;FormState&gt;();
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        bottomNavigationBar:
          ...
  
        body: Container(
          color: Colors.amber.withOpacity(0.80),
      child: Align(
      alignment: Alignment(0, 0),
          child: Form(
            key: _formkey,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: &lt;Widget&gt;[
                Container(
                          width: 300,
                          height: 300,
                          child: TextFormField(
                            keyboardType: TextInputType.number,
                            decoration: InputDecoration(
                                labelText: "RaspberryPi",
                                labelStyle: TextStyle(color: Colors.white)),
                            textAlign: TextAlign.center,
                            style: TextStyle(color: Colors.white, fontSize: 25.0),
                            validator: (value) {
                              if (value.isEmpty){
                                return "Insira";
                              }
                            },
                          ),
                        ),
                        Container(
                          decoration: BoxDecoration(
                            boxShadow: [
                              BoxShadow(
                               ...
                              ),
                            ],
                          ),
                          child: FlatButton(
                            color: Colors.white,
                            textColor: Colors.white,
                            disabledColor: Colors.grey,
                            disabledTextColor: Colors.black,
                            padding: EdgeInsets.all(8.0),
                            splashColor: Colors.blueAccent,
                            onPressed: () {
                              if(_formkey.currentState.validate()){
  
                              }
                            },
                            child: Text(
                              "Ligar",
                            ),
                  ),
                ),
              ],
            ),
          ),
        ),
        ),
      );
    }
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/BLir7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BLir7.png" alt="enter image description here"></a></p>