データがなくヘッダーのみの JTable を作成するクラスがあります
public class Test
{
private static int COLUMN_WIDTH[] = {75, 150, 75};
public static final String[] COLUMN_NAMES = {"One", "Two", "Three"};
public static void main (String [] args)
{
JFrame frame = new JFrame("Test");
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
// making column model and header
JTable table = new JTable(null, COLUMN_NAMES);
JTableHeader header = table.getTableHeader();
TableColumnModel tableModel = header.getColumnModel();
for(int i = 0; i < tableModel.getColumnCount(); i++)
{
tableModel.getColumn(i).setMinWidth(COLUMN_WIDTH[i]);
tableModel.getColumn(i).setPreferredWidth(COLUMN_WIDTH[i]);
}
panel.add(header);
// making children
Children child = new Children(tableModel);
child.add(panel);
child = new Children(tableModel);
child.add(panel);
child = new Children(tableModel);
child.add(panel);
// adding all
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
}
さらに、行数と値が絶えず変化する子がいます
public class Children
{
private JTable table;
public Children(TableColumnModel model)
{
table = new JTable(new Object[][] {{111, "One", 222}, {444, "Two", 333}, {555, "Three", 777}}, Test.COLUMN_NAMES);
table.setColumnModel(model);
}
public void add(JPanel panel)
{
panel.add(table);
}
}
それらのサイズを変更したり、列を好きなように移動したりしたいと思います。
しかし、列のサイズ変更はまったく機能しません
そして、列を移動したいときはいつでもこれを取得します
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.JTable$1.getRowCount(JTable.java:666)
at javax.swing.JTable.getRowCount(JTable.java:2627)
at javax.swing.JTable.columnSelectionChanged(JTable.java:4614)
at javax.swing.table.DefaultTableColumnModel.fireColumnSelectionChanged(DefaultTableColumnModel.java:588)
at javax.swing.table.DefaultTableColumnModel.valueChanged(DefaultTableColumnModel.java:693)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
at javax.swing.DefaultListSelectionModel.removeIndexInterval(DefaultListSelectionModel.java:660)
at javax.swing.table.DefaultTableColumnModel.moveColumn(DefaultTableColumnModel.java:180)
at javax.swing.plaf.basic.BasicTableHeaderUI$MouseInputHandler.mouseDragged(BasicTableHeaderUI.java:226)
at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:302)
at java.awt.Component.processMouseMotionEvent(Component.java:6345)
at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:3293)
at java.awt.Component.processEvent(Component.java:6066)
at java.awt.Container.processEvent(Container.java:2039)
at java.awt.Component.dispatchEventImpl(Component.java:4660)
at java.awt.Container.dispatchEventImpl(Container.java:2097)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4575)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4253)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4166)
at java.awt.Container.dispatchEventImpl(Container.java:2083)
at java.awt.Window.dispatchEventImpl(Window.java:2489)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:674)
at java.awt.EventQueue.access$400(EventQueue.java:81)
at java.awt.EventQueue$2.run(EventQueue.java:633)
at java.awt.EventQueue$2.run(EventQueue.java:631)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$3.run(EventQueue.java:647)
at java.awt.EventQueue$3.run(EventQueue.java:645)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:644)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
そして、任意の列をクリックすると、これが得られます
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.JTable$1.getRowCount(JTable.java:666)
at javax.swing.JTable.getRowCount(JTable.java:2627)
at javax.swing.JTable.columnSelectionChanged(JTable.java:4614)
at javax.swing.table.DefaultTableColumnModel.fireColumnSelectionChanged(DefaultTableColumnModel.java:588)
at javax.swing.table.DefaultTableColumnModel.valueChanged(DefaultTableColumnModel.java:693)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:388)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:398)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:442)
at javax.swing.JTable.changeSelectionModel(JTable.java:2348)
at javax.swing.JTable.changeSelection(JTable.java:2415)
at javax.swing.plaf.basic.BasicTableUI$Handler.adjustSelection(BasicTableUI.java:1085)
at javax.swing.plaf.basic.BasicTableUI$Handler.mousePressed(BasicTableUI.java:1008)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
at java.awt.Component.processMouseEvent(Component.java:6294)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3275)
at java.awt.Component.processEvent(Component.java:6062)
at java.awt.Container.processEvent(Container.java:2039)
at java.awt.Component.dispatchEventImpl(Component.java:4660)
at java.awt.Container.dispatchEventImpl(Container.java:2097)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4575)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4233)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4166)
at java.awt.Container.dispatchEventImpl(Container.java:2083)
at java.awt.Window.dispatchEventImpl(Window.java:2489)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:674)
at java.awt.EventQueue.access$400(EventQueue.java:81)
at java.awt.EventQueue$2.run(EventQueue.java:633)
at java.awt.EventQueue$2.run(EventQueue.java:631)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$3.run(EventQueue.java:647)
at java.awt.EventQueue$3.run(EventQueue.java:645)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:644)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
この問題を解決する方法について何か提案はありますか? 私のアプローチが間違っている場合、テーブルから行をすばやく効率的に変更および追加および削除し続ける方法を誰かが推奨できますか?
アドバイスをありがとう。