minLines property
The minimum number of lines to occupy when the content spans fewer lines.
This affects the height of the field itself and does not limit the number of lines that can be entered into the field.
If this is null (default), text container starts with enough vertical space for one line and grows to accommodate additional lines as they are entered.
This can be used in combination with maxLines for a varying set of behaviors.
If the value is set, it must be greater than zero. If the value is greater than 1, maxLines should also be set to either null or greater than this value.
When maxLines is set as well, the height will grow between the indicated range of lines. When maxLines is null, it will grow as high as needed, starting from minLines.
Implementation
final int? minLines;