frozencolumnheader.java

< ProJavaProgrammingSecondEdition> 书中例程源码

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;

public class FrozenColumnHeader extends JScrollPane {

  protected JTable mainTable;
  protected JTable headerTable;
  protected int columnCount;

  public FrozenColumnHeader(JTable table, int columns) {
    super();
    mainTable = table;
    headerTable = new JTable(mainTable.getModel());
    getViewport().setView(headerTable);
    columnCount = columns;
  }

  public void addNotify() {
    TableColumn column;
    super.addNotify();
    TableColumnModel mainModel = mainTable.getColumnModel();
    TableColumnModel headerModel = new DefaultTableColumnModel();
    int frozenWidth = 0;
    for (int i = 0; i < columnCount; i++) {
      column = mainModel.getColumn(0);
      mainModel.removeColumn(column);
      headerModel.addColumn(column);
      frozenWidth += column.getPreferredWidth() + headerModel.getColumnMargin();
    } 
    headerTable.setColumnModel(headerModel);
    Component columnHeader = getColumnHeader().getView();
    getColumnHeader().setView(null);
    JScrollPane mainScrollPane = (JScrollPane)SwingUtilities.getAncestorOfClass(
        JScrollPane.class, mainTable);
    mainScrollPane.setCorner(JScrollPane.UPPER_LEFT_CORNER, columnHeader);
    headerTable.setPreferredScrollableViewportSize(
        new Dimension(frozenWidth, 0));
  } 

}