How to expand a textField in flutter looks like a text Area

When i tap in textField in landScape mode i would like to expand in full screen likes whatsapp

            TextFormField(
              keyboardType: TextInputType.number,
              decoration: InputDecoration(
                  prefixIcon: Padding(
                    padding: EdgeInsets.all(0.0),
                    child: Icon(Icons.person,
                        size: 40.0, color: Colors.white),
                  ),
                  hintText: "Input your opinion",
                  hintStyle: TextStyle(color: Colors.white30),
                  border: OutlineInputBorder(
                      borderRadius:
                      BorderRadius.all(new Radius.circular(25.0))),
                  labelStyle: TextStyle(color: Colors.white)),
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Colors.white,
                fontSize: 25.0,
              ),
              controller: host,
              validator: (value) {
                if (value.isEmpty) {
                  return "Empty value";
                }
              },
            )

All you need to do is set the maxLines variable when creating a TextField. I have added the text field inside a Card widget so you can see the total area.

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Simple Material App"),
      ),
      body: Column(
        children: <Widget>[
          Card(
            color: Colors.grey,
            child: Padding(
              padding: EdgeInsets.all(8.0),
              child: TextField(
                maxLines: 8, //or null 
                decoration: InputDecoration.collapsed(hintText: "Enter your text here"),
              ),
            )
          )
        ],
      )
    );
  }