import com.google.gwt.cell.client.AbstractEditableCell; //导入依赖的package包/类
/**
 * Add a column with a header.
 * 
 * @param <C> the cell type
 * @param cell the cell used to render the column
 * @param headerText the header string
 * @param getter the value getter for the cell
 */
@ShowcaseSource
private <C> Column<ContactInfo, C> addColumn(Cell<C> cell, String headerText,
    final GetValue<C> getter, FieldUpdater<ContactInfo, C> fieldUpdater) {
  Column<ContactInfo, C> column = new Column<ContactInfo, C>(cell) {
    @Override
    public C getValue(ContactInfo object) {
      return getter.getValue(object);
    }
  };
  column.setFieldUpdater(fieldUpdater);
  if (cell instanceof AbstractEditableCell<?, ?>) {
    editableCells.add((AbstractEditableCell<?, ?>) cell);
  }
  contactList.addColumn(column, headerText);
  return column;
}