Do you need to worry here? What is still "drawing cells that are no longer being used"? Are you running some kind of update in a background thread on the WaveformTraceBox?
In any event, you've structured this pretty strangely.
First, (less important) why is your WaveformTraceBoxTreeTableViewCell
generic? Surely you want
protected static class WaveformTraceBoxTreeTableViewCell extends TreeTableCell<DrawRow, WaveformTraceBox>
and then you can replace T
with WaveformTraceBox
throughout and get rid of the casts, etc.
Second: if I understand this correctly, WaveformTraceBox
is a custom Node
subclass of some kind; i.e. it's a UI component. The cell value factory shouldn't really return a UI component - it should return the data to display. The cell factory should then use some UI component to display the data.
That way, you can create a single WaveFormTraceBox in the cell implementation, and update the data it displays in the updateItem(...)
method.
So something like:
// Waveform column
TreeTableColumn<DrawRow, WaveformData> waveColumn = new TreeTableColumn<>();
waveColumn.setCellFactory(new Callback<TreeTableColumn<DrawRow, WaveformData>, TreeTableCell<DrawRow, WaveformData>>() {
@Override
public TreeTableCell<DrawRow, WaveformData> call(TreeTableColumn<DrawRow, WaveformData> param) {
return new WaveformTraceBoxTreeTableViewCell();
}
});
waveColumn.setCellValueFactory(new Callback<TreeTableColumn.CellDataFeatures<DrawRow, WaveformData>, ObservableValue<WaveformData>>() {
@Override
public ObservableValue<WaveformTraceBox> call(TreeTableColumn.CellDataFeatures<DrawRow, WaveformTraceBox> param) {
return new ReadOnlyObjectWrapper<>(getDataToDisplayForItem(param.getValue()));
}
});
protected static class WaveformTraceBoxTreeTableViewCell extends TreeTableCell<DrawRow, WaveFormData> {
private WaveformTraceBox traceBox = new WaveformTraceBox();
public WaveformTraceBoxTreeTableViewCell() {
super();
}
@Override
protected void updateItem(WaveFormData value, boolean empty) {
super.updateItem(value, empty);
setText(null);
setGraphic(null);
if (!empty && getTreeTableRow().getItem() != null) {
traceBox.setData(value);
setGraphic(traceBox);
} else {
setGraphic(null);
}
}
}
Obviously you need to define the WaveFormData class to encapsulate the data your WaveFormTraceBox
will display, and give the WaveFormTraceBox
a setData(WaveFormData)
method. If you are using any resources that need to be cleaned up, the invocation of setData(...)
will indicate that the previous data is no longer being accessed by that WaveformTraceBox
.