title: Duplicate GlobalKey detected in widget tree Flutter
body: <p>I have a list view which has a card as a child of list view. The card contains a TextFormField with a form key. Since it is a listview it builds the card multiple times with the same form key so it is giving error:</p>
  
  <pre><code>Duplicate GlobalKey detected in widget tree.
  </code></pre>
  
  <p>Please help me with this.</p>
  
  <p>This is my code.</p>
  
  <pre><code>  final GlobalKey&lt;FormState&gt; _formKey =
    new GlobalKey&lt;FormState&gt;(debugLabel: ' _formKey');
  
   @override
   Widget build(BuildContext context) {
  
  return  Card(
      margin: EdgeInsets.symmetric(
        horizontal: 15,
        vertical: 4,
      ),
      child: Padding(
        padding: EdgeInsets.all(8),
        child: Column(
          children: &lt;Widget&gt;[
            ListTile(
              leading: CircleAvatar(
                backgroundColor: Colors.blue,
                child: Padding(
                  padding: EdgeInsets.all(5),
                  child: FittedBox(
                    child: Text(
                      widget.price,
                      style: TextStyle(color: Colors.white),
                    ),
                  ),
                ),
              ),
              title: Text('Title'),
              subtitle: Text('Subtitle'),
              trailing: Text(widget.quantity.toString() + ' x'),
            ),
  
            Padding(
                padding: const EdgeInsets.only(
                    left: 32, right: 5, top: 0, bottom: 5),
                child: Container(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.start,
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: &lt;Widget&gt;[
                      new Form(
                        key: this._formKey,
                        child: new TextFormField(
                          decoration: new InputDecoration(
                              hintText: 'Add your comments',
                              labelText: 'Comments'),
                          // validator: this._validateEmail,
                          onSaved: (String value) {
                            //  _formKey.currentState.save();
  
                          },
                        ),
                      ),
  
                    ],
                  ),
  
                ))
  
    }
  </code></pre>