title: Using FocusNode in TextFormField Flutter
body: <p>I have a <code>TextFormField</code> that is supposed to receive digits. On entry of first digit it should jump to second <code>TextFormField</code> then to the third TextFormField. Each <code>TextFormField</code> has the <code>FocusNode</code> property I just do not know how to use it. I have this</p>
  <pre><code>TextFormField(     //First Field                            
       autofocus: true,
       focusNode: FocusNode(),
       decoration: InputDecoration(
       border: OutlineInputBorder(
       borderRadius: BorderRadius.circular(4.0)
        ),
        ),
       style: TextStyle(
        color: Colors.orange,
        fontSize: 15.0,
        ),
       keyboardType:
        TextInputType.number,
       maxLength: 1,
        ),
  
      // second Field
     TextFormField(),
  
      //third Field
  </code></pre>