SWT-ComboBoxCellEditor /默认值

Question

I would like for my ComboBoxCellEditor to be able to have 3 selections possible. Right now it only has Yes or No. I would like for it to have Yes, No, Both.

Also the combobox selection values does not show up in the table unless the cell is clicked. It is hard to tell if the table cell has a selection possible unless they click in the empty cell. I would like it to at least show the down arrow.
I have read some where that the only way you can get around this is to set a default value.

1. I am not sure how to add the 3rd value. I will add my code trying to add the 3rd value

2. How can a get the combobox show up in the table without the cell having to be clicked first?

.

public class OptionEditingSupport extends EditingSupport {

    private ComboBoxCellEditor cellEditor;

    public OptionEditingSupport(ColumnViewer viewer) {
        super(viewer);
        cellEditor = new ComboBoxCellEditor(((TableViewer)viewer).getTable(), new String[]{"Yes", "No", "Both"}, SWT.READ_ONLY);

    }

    protected CellEditor getCellEditor(Object element) {
        return cellEditor;
    }

    protected boolean canEdit(Object element) {
        return true;
    }

    protected Object getValue(Object element) {
        return 0;
    }

    protected void setValue(Object element, Object value) 
    {
        if((element instanceof AplotDatasetData) && (value instanceof Integer)) {
            Integer choice = (Integer)value;
            String option = (choice == 0? "Yes":"No":"Both"); **<- Error Here
            ((AplotDatasetData)element).setMarkupValue(option);
            getViewer().update(element, null);
        }
    }
}

Answer 1

The conditional operator

x ? y : z

is a ternary operator, which internally does:

if(x)
    y;
else
    z;

Thus, you can only use it with three components. Use an if else if else instead:

Integer choice = (Integer)value;
String option = "";

if(choice == 0)
    option = "Yes";
else if(choice == 1)
    option = "No";
else
    option = "Both";

Answer 2

TableEditor can be used to show any Widget on top of Table Cell. It should solve your problem with showing Combobox to let user know there is selection possible for that row and column.

I am not sure I understand your question about 3 selections.