當相應的列有空值時，我可以從jtable中刪除複選框嗎？

Question

我在jTable中有2列。第一列項目名稱和第二列是複選框添加列。 我試圖將複選框添加到jTable列中，但複選框正在添加到所有列單元格中。但是我想添加複選框僅用於itemname列中具有值的相應單元格。如果itemname值爲null，那麼對應的複選框列也是我想要的設置爲null。

Answer 1

使用您自己的TableCellEditor和TableCellRenderer，您可以決定想要顯示什麼。下面是一個例子，我「玩」複選框的知名度每三排：

import java.awt.BorderLayout; 
import java.awt.Component; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.util.ArrayList; 
import java.util.EventObject; 
import java.util.List; 

import javax.swing.JCheckBox; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.JTable; 
import javax.swing.SwingUtilities; 
import javax.swing.UIManager; 
import javax.swing.UnsupportedLookAndFeelException; 
import javax.swing.event.CellEditorListener; 
import javax.swing.event.ChangeEvent; 
import javax.swing.table.AbstractTableModel; 
import javax.swing.table.DefaultTableCellRenderer; 
import javax.swing.table.TableCellEditor; 
import javax.swing.table.TableCellRenderer; 

public class TestTable { 

    private JFrame f; 
    private JTable table; 

    private class MyCheckBoxRendererEditor extends JPanel implements TableCellRenderer, TableCellEditor, ActionListener { 
     private JCheckBox checkbox; 

     DefaultTableCellRenderer defaultRenderer; 

     public MyCheckBoxRendererEditor() { 
      defaultRenderer = new DefaultTableCellRenderer(); 
      checkbox = new JCheckBox(); 
      checkbox.setOpaque(false); 
      checkbox.addActionListener(this); 
      checkbox.setRequestFocusEnabled(false); 
      setOpaque(true); 
      add(checkbox); 
      validate(); 
     } 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      stopCellEditing(); 
     } 

     @Override 
     public Object getCellEditorValue() { 
      return checkbox.isSelected(); 
     } 

     @Override 
     public boolean isCellEditable(EventObject anEvent) { 
      return true; 
     } 

     @Override 
     public boolean shouldSelectCell(EventObject anEvent) { 
      return true; 
     } 

     @Override 
     public boolean stopCellEditing() { 
      for (CellEditorListener listener : getListeners(CellEditorListener.class)) { 
       listener.editingStopped(new ChangeEvent(this)); 
      } 
      return true; 
     } 

     @Override 
     public void cancelCellEditing() { 
      for (CellEditorListener listener : getListeners(CellEditorListener.class)) { 
       listener.editingCanceled(new ChangeEvent(this)); 
      } 
     } 

     @Override 
     public void addCellEditorListener(CellEditorListener l) { 
      this.listenerList.add(CellEditorListener.class, l); 
     } 

     @Override 
     public void removeCellEditorListener(CellEditorListener l) { 
      this.listenerList.remove(CellEditorListener.class, l); 
     } 

     @Override 
     public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) { 
      configure(table, value, true, true, row, column); 
      return this; 
     } 

     @Override 
     public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) { 
      configure(table, value, isSelected, hasFocus, row, column); 
      return this; 
     } 

     private void configure(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) { 
      defaultRenderer.setBackground(null); 
      defaultRenderer.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column); 
      MyObject myObject = ((MyTableModel) table.getModel()).getValueAt(row); 
      checkbox.setVisible(myObject.getValue() != null); 
      checkbox.setSelected((Boolean) value); 
      setBackground(defaultRenderer.getBackground()); 
      setBorder(defaultRenderer.getBorder()); 
     } 

    } 

    private class MyObject { 
     private final String value; 
     private boolean checked; 

     public MyObject(String value) { 
      this.value = value; 
     } 

     public String getValue() { 
      return value; 
     } 

     public boolean isChecked() { 
      return checked; 
     } 

     public void setChecked(boolean checked) { 
      this.checked = checked; 
      System.err.println(value + " is " + checked); 
     } 
    } 

    protected void initUI() { 
     List<MyObject> data = new ArrayList<TestTable.MyObject>(); 
     for (int i = 0; i < 20; i++) { 
      MyObject object = new MyObject(i % 3 == 1 ? null : "Row " + (i + 1)); 
      data.add(object); 
     } 
     table = new JTable(new MyTableModel(data)); 
     table.getColumnModel().getColumn(1).setCellEditor(new MyCheckBoxRendererEditor()); 
     table.getColumnModel().getColumn(1).setCellRenderer(new MyCheckBoxRendererEditor()); 
     table.setRowHeight(30); 
     f = new JFrame(); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     f.add(new JScrollPane(table), BorderLayout.CENTER); 
     f.pack(); 
     f.setVisible(true); 

    } 

    public class MyTableModel extends AbstractTableModel { 

     private List<MyObject> data; 

     public MyTableModel(List<MyObject> data) { 
      super(); 
      this.data = data; 
     } 

     @Override 
     public int getColumnCount() { 
      return 2; 
     } 

     @Override 
     public int getRowCount() { 
      return data.size(); 
     } 

     public MyObject getValueAt(int row) { 
      return data.get(row); 
     } 

     @Override 
     public Object getValueAt(int rowIndex, int columnIndex) { 
      switch (columnIndex) { 
      case 0: 
       return getValueAt(rowIndex).getValue(); 
      case 1: 
       return getValueAt(rowIndex).isChecked(); 
      } 
      return null; 
     } 

     @Override 
     public void setValueAt(Object aValue, int rowIndex, int columnIndex) { 
      if (columnIndex == 1) { 
       getValueAt(rowIndex).setChecked((Boolean) aValue); 
      } 
     } 

     @Override 
     public boolean isCellEditable(int rowIndex, int columnIndex) { 
      return columnIndex == 1 && getValueAt(rowIndex).getValue() != null; 
     } 

     @Override 
     public Class<?> getColumnClass(int column) { 
      switch (column) { 
      case 0: 
       return String.class; 
      case 1: 
       return Boolean.class; 
      } 
      return Object.class; 
     } 

     @Override 
     public String getColumnName(int column) { 
      switch (column) { 
      case 0: 
       return "Value"; 
      case 1: 
       return "Checked"; 
      } 
      return null; 
     } 

    } 

    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, 
      UnsupportedLookAndFeelException { 
     UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       new TestTable().initUI(); 
      } 
     }); 
    } 

}