Editable multiline cell in TableView - javafx

Question

(There already is a question regarding this but it has no answer and the comment isn't helpful either.)
I've got a TableView and I'd like to have a column with multiline labels that I can edit. Ideally, the behaviour would be like a TextFieldTableCell but with multiline support:
It displays text like a label.
When clicked, it transforms into a TextField (or in this case, a TextArea) so the text can be edited.
I haven't found a solution for this yet. The only workaround I've got right now is put a TextArea as the cell's "graphic":
descriptionTableColumn.setCellFactory(param -> new TableCell<Attachment, String>() {
#Override
protected void updateItem(String item, boolean empty) {
if (empty) {
setGraphic(null);
} else {
TextArea area = new TextArea(item);
area.setMinHeight(USE_COMPUTED_SIZE);
area.setPrefHeight(USE_COMPUTED_SIZE);
area.setMaxHeight(USE_COMPUTED_SIZE);
setGraphic(area);
}
}
});
(Code to listen to the text changes is missing here; it doesn't trigger the OnEditCommit event.)
However, the TextArea is always rendered as a normal TextArea with a border and white background. I can live with that. But the area also always renders with a certain height (about 180px) even when it's empty, even though I set USE_COMPUTED_SIZE.
So the question is:
Is there a way to get the ideal behaviour, similar to the TextFieldTableCell?
If not, is there a way to have the TextArea only use as much height as needed?

Answer 1

Ok, the basic idea is to copy the TextFieldTableColumn and adjust its behavior to create a TextAreaTableColumn. I hacked a small working example implementation together: https://gist.github.com/eckig/30abf0d7d51b7756c2e7
Usage:
TableColumn<?, ?> column = new TableColumn<>();
column.setCellValueFactory(...);
column.setCellFactory(TextAreaTableCell.forTableColumn()); // add StringConverter if neccessary
tableView.getColumns().add(column);
But, there are still some things left which need to be implemented / some tuning:
Adjust prefRowCount to show only the necessary amount of rows.
Maybe adjust prefColumnCount?
Because the "Enter" Key gets consumed for a new-line, I had to add a Save Button to commit the edit. This is somewhat ugly, but for now I do not have a better idea.
But hopefully you get the idea ;-)