如何在应用MaskFormatter后使JTable单元格中的插入符号显示在左边

Question

SSCCE：

public class TableExample extends JFrame {
    public TableExample() {
        add(makeTable());
    }

    private JTable makeTable() {
        Object[][] tableData = {{"","a","b",""}, {"","c","d",""}};
        String[] columns = {"column1", "column2", "column3", "dobColumn"};
        JTable table = new JTable(tableData, columns);

        ////DOB column formats to dd/mm/yy
        TableColumn dobColumn = table.getColumnModel().getColumn(3);
        DateFormat df = new SimpleDateFormat("dd/mm/yy");
        JFormattedTextField tf = new JFormattedTextField(df);
        tf.setColumns(8);
        try {
            MaskFormatter dobMask = new MaskFormatter("##/##/##");
            dobMask.setPlaceholderCharacter('0');
            dobMask.install(tf);
        } catch (ParseException ex) {
             Logger.getLogger(TableExample.class.getName()).log(Level.SEVERE, null, ex);
        }

        ////Does nothing
        tf.setCaretPoisition(0);

        dobColumn.setCellEditor(new DefaultCellEditor(tf));

        return table;
    }

    public static void main(String[] args) {
        JFrame frame = new TableExample();
        frame.setSize( 300, 300 );
        frame.setVisible(true); 
    }
}

Answer 1

如果我没记错，您可以将FocusListener添加到格式化文本字段中，然后当组件获得焦点时，您可以调用SetCaretPosition(0)方法。

但是，该语句必须包装在swingUtilities.invokelater(...)中，以确保代码在格式化文本字段的默认插入符号定位之后执行。

另一个选项是重写JTable的iscelleditable(...)方法。但是，这种方法将影响表中的所有编辑器。

public boolean editCellAt(int row, int column, EventObject e)
{
    boolean result = super.editCellAt(row, column, e);
    final Component editor = getEditorComponent();

    if (editor != null && editor instanceof JTextComponent)
    {
        ((JTextComponent)editor).selectAll();

        if (e == null)
        {
            ((JTextComponent)editor).selectAll();
        }
        else if (e instanceof MouseEvent)
        {
            SwingUtilities.invokeLater(new Runnable()
            {
                public void run()
                {
                    ((JTextComponent)editor).selectAll();
                }
            });
        }

    }

    return result;
}