Multi-line Textfield in flutter

Question

It may sound easy but How can we do a multi-line editable textfield in flutter? TextField works only with a single line.

Edit: some precisions beca

Answer 1

Although other people already mentioned that the keyboard type "TextInputType.multiline" can be used, I wanted to add my implementation of a TextField that automatically adapts its height when a new line is entered, as it is often desired to immitate the input behaviour of WhatsApp and similar apps.

I'm analyzing the number of '\n' chatacters in the input for this purpose each time the text is changed. This seems to be an overkill, but unfortunately I didn't find a better possibility to achieve this beahivour in Flutter so far and I didn't notice any performance problems even on older smartphones.

class _MyScreenState extends State<MyScreen> {
  double _inputHeight = 50;
  final TextEditingController _textEditingController = TextEditingController();

  @override
  void initState() {
    super.initState();
    _textEditingController.addListener(_checkInputHeight);
  }

  @override
  void dispose() {
    _textEditingController.dispose();
    super.dispose();
  }

  void _checkInputHeight() async {
    int count = _textEditingController.text.split('\n').length;

    if (count == 0 && _inputHeight == 50.0) {
      return;
    }
    if (count <= 5) {  // use a maximum height of 6 rows 
    // height values can be adapted based on the font size
      var newHeight = count == 0 ? 50.0 : 28.0 + (count * 18.0);
      setState(() {
        _inputHeight = newHeight;
      });
    }
  }


  // ... build method here
  TextField(
    controller: _textEditingController,
    textInputAction: TextInputAction.newline,
    keyboardType: TextInputType.multiline,
    maxLines: null,
  )

Answer 2

Use expands and you don't need to give minLines or maxLines any specific value:

TextField(
  maxLines: null,
  expands: true, 
  keyboardType: TextInputType.multiline,
)

Answer 3

use this

TextFormField(
      keyboardType: TextInputType.multiline,
      maxLines: //Number_of_lines(int),)

Answer 4

   TextFormField(
                  minLines: 2,
                  maxLines: 5,
                  keyboardType: TextInputType.multiline,
                  decoration: InputDecoration(
                    hintText: 'description',
                    hintStyle: TextStyle(
                      color: Colors.grey
                    ),
                    border: OutlineInputBorder(
                      borderRadius: BorderRadius.all(Radius.circular(20.0)),
                    ),
                  ),
                ),

Answer 5

For TextFormField widget, You can set minLines and maxLines if you want to set fix number of lines. Otherwise you can also set maxLines to null.

TextFormField(
      minLines: 5,
      maxLines: 7,
      decoration: InputDecoration(
          hintText: 'Address',
          border: OutlineInputBorder(
              borderRadius: BorderRadius.all(Radius.circular(10.0)),
          ),
      ),
),