events - 复选框单元格事件

Question

GWT 2.4 我有CheckBoxCell一个CellTable. 选中/取消选中复选框后，更改事件会触发两次。我不知道为什么。任何帮助将不胜感激。

private void createTable() {

    // Create a CellTable with a key provider.
    final CellTable<Contact> table = new CellTable<Contact>(KEY_PROVIDER);

    // Add a checkbox column
    final CheckboxCell cbCell = new CheckboxCell();
    Column<Contact, Boolean> cbColumn = new Column<Contact, Boolean>(cbCell) {
        @Override
        public Boolean getValue(Contact object) {
            System.out.println("method getValue() - " + object.id + " - " + object.checked);
            return object.checked;
        }
    };

    cbColumn.setFieldUpdater(new FieldUpdater<Fieldupdater.Contact, Boolean>() {
        @Override
        public void update(int index, Contact object, Boolean value) {
            System.out.println("method update() - " + object.id + " - " + value);
        }
    });

    table.addColumn(cbColumn);

    // Push the data into the widget.
    table.setRowData(CONTACTS);

    // Add it to the root panel.
    RootPanel.get("table1").add(table);
}