change textfield to text flutter code example

Example 1: change text in text feild flutter

TextField(
      controller: txt,
    ),
    RaisedButton(onPressed: () {
        txt.text = "My Stringt";
    }),

Example 2: flutter text replace in a textfield

final _newValue = "New value";
_controller.value = TextEditingValue(
      text: _newValue,
      selection: TextSelection.fromPosition(
        TextPosition(offset: _newValue.length),
      ),
    );