JTable dynamisch Zeilen hinzufügen und entfernen: Unterschied zwischen den Versionen

Aus Byte-Welt Wiki
Zur Navigation springenZur Suche springen
K
K
Zeile 105: Zeile 105:
 
[[Kategorie:Java-Codeschnipsel]]
 
[[Kategorie:Java-Codeschnipsel]]
  
Basieren auf einem Codebeispiel von Marco13
+
<span style="font-size:9px; color:aaa;">(Basierend auf einem Codebeispiel von Marco13)</span>

Version vom 27. Mai 2014, 11:22 Uhr

Mit folgendem Code kann man, ähnlich wie in Excel Zeilen dynamisch beim Scrollen in die JTable einfügen oder auch leere, nicht benutzte Zeilen wieder löschen.

<code=java> import java.awt.*; import java.awt.event.*;

import javax.swing.*; import javax.swing.table.*;

public class DynamicRows extends JFrame implements AdjustmentListener {

   private JScrollPane jScrollPane1;
   private JTable jTable1;
   private DefaultTableModel model;
   private int yVisible, yVisibleOld;
   private boolean valueIsAdjusting = false;
   public DynamicRows() {
       super("DynamicRows");
       setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
       setSize(400, 300);
       setLocationRelativeTo(null);
       jScrollPane1 = new JScrollPane();
       jTable1 = new JTable();
       jTable1.setModel(new DefaultTableModel(
               new Object[][]{},
               new String[]{
                   "Title 1", "Title 2", "Title 3", "Title 4"
               }));
       jScrollPane1.setViewportView(jTable1);
       getContentPane().add(jScrollPane1, BorderLayout.CENTER);
       model = (DefaultTableModel) jTable1.getModel();
       for (int i = 0; i < 20; i++) {
           model.addRow(new Object[]{null, null, null, null});
       }
       jScrollPane1.getVerticalScrollBar().addAdjustmentListener(this);
   }
   public void adjustmentValueChanged(final AdjustmentEvent e) {
       if (e.getValueIsAdjusting()) {
           valueIsAdjusting = true;
           return;
       }
       Adjustable a = e.getAdjustable();
       Rectangle rectBottom = jTable1.getCellRect(model.getRowCount() - 1, 0, true);
       int yBottom = rectBottom.y + rectBottom.height;
       Rectangle rectVisible = jTable1.getVisibleRect();
       yVisible = rectVisible.y + rectVisible.height;
       //if we are scrolling upwards:
       if (yVisible != 0 && yVisible < yVisibleOld) {
           //remove all invisible rows if they area empty (from bottom to top):
           boolean remove = true;
           for (int row = jTable1.getRowCount() - 1; row > -1; row--) {
               if (jTable1.getCellRect(row, 0, true).y > yVisible) {//if row is invisible
                   for (int column = 0; column < jTable1.getColumnCount(); column++) {
                       Object value = jTable1.getValueAt(row, column);
                       if (value != null) {//if the row is not empty
                           remove = false;//do not remove any more rows
                       }
                   }
                   if (remove) {
                       model.removeRow(row);
                   }
               }
           }
       } else {

//here we are scrolling downwards

           //if visible area is at bottom:
           if ((yBottom == yVisible)) {
               if (valueIsAdjusting) {
                   valueIsAdjusting = false;
                   rectVisible.y = rectVisible.y - 2;
                   yVisible = yVisible - 2;
                   jTable1.scrollRectToVisible(rectVisible);
               } else {
                   a.removeAdjustmentListener(this);
                   //add new row and scroll to visible:
                   model.addRow(new Object[]{null, null, null, null});
                   rectBottom = jTable1.getCellRect(model.getRowCount() - 1, 0, true);
                   rectBottom.height = rectBottom.height - 1;
                   jTable1.scrollRectToVisible(rectBottom);
                   a.addAdjustmentListener(this);
               }
           }
       }
       yVisibleOld = yVisible;
   }
   public static void main(final String args[]) {
       EventQueue.invokeLater(new Runnable() {
           public void run() {
               new DynamicRows().setVisible(true);
           }
       });
   }

} </code=java>

(Basierend auf einem Codebeispiel von Marco13)