Disabling HTML support in a JLabel

Sometimes, it may be necessary to display html tags inside a JLabel. If the text of an HTML enabled JComponent like JLabel starts with then this text will be rendered as HTML. To prevent this rendering from happening, set the clientproperty html of that JLabel to null.

Main.java:

import javax.swing.plaf.basic.*;
import java.awt.event.*;
import java.awt.font.*; 
import javax.swing.*;
import java.util.*;
import java.text.*;
import java.awt.*;
   
public class Main extends JFrame {
   public Main() {
      getContentPane().setLayout(new FlowLayout());
 
      final JLabel label = new JLabel("<html><h1>Test disable html</h1></html>");
      getContentPane().add(label);
 
      label.putClientProperty("html", null);
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent event) {
            System.exit(0);   
         }      
      });
 
      pack();
   }
 
   public static void main(String[] args) {
      (new Main()).show();
   }
}

Displaying a dialog window to save files

This following example will use Swings JFileChooser to display a save dialog box and allow the user to make a selection.
It will set the current directory to c: and set the default selection to autoexec.bat. Notice that multiple file selections are not implemented for the current look and feels (see the JFileChooser API).
The method showSaveDialog will block until a file has been selected. It returns APPROVE_OPTION if OK has been clicked, CANCEL_OPTION otherwise.

import java.awt.event.*;
import javax.swing.*;
import java.io.*;
 
public class Main extends JFrame
{
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
 
   public Main() {
      JButton fileButton = new JButton("Select File");
      fileButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            File file = getFileFromUser();
            if (file != null)
               System.out.println(file.getName());
         }
      });
      getContentPane().add(fileButton);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
 
      pack();
   }
  
   public File getFileFromUser() {
      JFileChooser fc = new JFileChooser();
 
      // use current directory
      fc.setCurrentDirectory(new File("c:\"));
 
      // set default name
      fc.setSelectedFile(new File("autoexec.bat"));
 
      // show dialog for opening files
      int result = fc.showSaveDialog(this);
 
      if (result != fc.APPROVE_OPTION) 
         return null;
       
      return fc.getSelectedFile();
   }
}

Creating a JTable with a TableModel

A JTable can be passed the values the table should contain during construction, using a 2d array or a Vector. Creating a table with these constructors has some restrictions, like all data elements are rendered as String values or all cell elements are editable. To be more flexible, you can create your own custom TableModel that basically encapsulates the table data and provides some semantic knowledge about the data to be able to render it with an appropriate visual component. For example, you may wish to get the table values from a database as they become available or you might want to render a JProgressBar inside a table cell. Your custom table model should implement the interface TableModel, but you could simply extend from AbstractTableModel (a standard JDK class that implements TableModel) and override its methods.

The following example will create a simple table model that contains data about wines. The table is not editable but rows can be added by calling the method addWine to the model. Notice that this method contains a call to fireTableRowsInserted to tell the view to render the added row. Internally, the model uses a Vector to hold the data. The following API methods were implemented:

  • getColumnCount: called by the view to determine how many columns there are. The column names (headers) are hardcoded in an array. Return the length of this array.
  • getRowCount: called by the view to determine how many rows there are. As the vector contains our data, we return the size of the vector.
  • getColumnName: called by the view to render the column headers. Returns the element in our hardcoded header array.
  • getColumnClass: called by the view to determine what renderer to use for the specified column index. In the superclass, AbstractTableModel, this method returns Object.class, meaning it will treat and render all cells the same (as Objects, the toString() method is called on them when rendering). However, we’d like our member variable inStock to be rendered as a CheckBox instead of “true” or “false”. Therefore we return the Class of the column (hardcoded in the array columnClasses). This is enough for the view to know it should render column 4 as a JCheckBox instead of a JLabel. The data types Boolean, Number, ImageIcon and Object are recognized automatically and the view will use an appropriate cell renderer for them. Check out other questions in this category on how to create your own renderers eg. JProgressBar.
  • getValueAt: called by the view to determine a value at a particular row and column. From the row, we can get the Wine element out of our vector. The column determines what method to call on that object.
  • isCellEditable: called by the view to determine if a cell is editable or not. We return false in all cases.

Main.java:

import javax.swing.table.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
 
public class Main extends JFrame {
   public Main() {
      super("TableModel Demonstration");
 
      // create our own custom TableModel
      WineTableModel wineModel = new WineTableModel();
      JTable table = new JTable(wineModel);
 
      // add rows to our TableModel, each row is represented as a Wine object
      wineModel.addWine(new Wine("Chateau Meyney, St. Estephe", "1994", 18.75f, true));
      wineModel.addWine(new Wine("Chateau Montrose, St. Estephe", "1975", 54.25f, true));
      wineModel.addWine(new Wine("Chateau Gloria, St. Julien", "1993", 22.99f, false));
      wineModel.addWine(new Wine("Chateau Beychevelle, St. Julien", "1970", 61.63f, false));
      wineModel.addWine(new Wine("Chateau La Tour de Mons, Margeaux", "1975", 57.03f, true));
      wineModel.addWine(new Wine("Chateau Brane-Cantenac, Margeaux", "1978", 49.92f, false));
 
      // create the scroll pane and add the table to it. 
      JScrollPane scrollPane = new JScrollPane(table);
 
      // add the scroll pane to this window.
      getContentPane().add(scrollPane, BorderLayout.CENTER);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String[] args) {
      Main main = new Main();
      main.pack();
      main.setVisible(true);
   }
}
 
// a simple object that holds data about a particular wine
class Wine {
   private String  name;
   private String  vintage;
   private float   price;
   private boolean inStock;
 
   public Wine(String name, String vintage, float price, boolean inStock) {
      this.name = name;
      this.vintage = vintage;
      this.price = price;
      this.inStock = inStock;
   }
 
   public String getName()     { return name; }
   public String getVintage()  { return vintage; }
   public float  getPrice()    { return price; } 
   public boolean getInStock() { return inStock; }
 
   public String toString() { 
      return "[" + name + ", " + vintage + ", " + price + ", " + inStock + "]"; }
}
 
class WineTableModel extends AbstractTableModel {
   // holds the strings to be displayed in the column headers of our table
   final String[] columnNames = {"Name", "Vintage", "Price", "In stock?"};
 
   // holds the data types for all our columns
   final Class[] columnClasses = {String.class, String.class, Float.class, Boolean.class};
 
   // holds our data
   final Vector data = new Vector();
  
   // adds a row
   public void addWine(Wine w) {
      data.addElement(w);
      fireTableRowsInserted(data.size()-1, data.size()-1);
   }
 
   public int getColumnCount() {
      return columnNames.length;
   }
         
   public int getRowCount() {
      return data.size();
   }
 
   public String getColumnName(int col) {
      return columnNames[col];
   }
 
   public Class getColumnClass(int c) {
      return columnClasses1;
   }
 
   public Object getValueAt(int row, int col) {
      Wine wine = (Wine) data.elementAt(row);
      if (col == 0)      return wine.getName();
      else if (col == 1) return wine.getVintage();
      else if (col == 2) return new Float(wine.getPrice());
      else if (col == 3) return new Boolean(wine.getInStock());
      else return null;
   }
 
   public boolean isCellEditable(int row, int col) {
      return false;
   }
}

Sorting the rows in a JTable by clicking on a column header

Courtesy of Nobuo Tamemasa (http://www2.gol.com/users/tame/swing/examples/JTableExamples5.html)



SortableTableExample.java:

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.text.*;
import javax.swing.*;
import javax.swing.table.*;
  
/**
 * @version 1.0 02/25/99
 */
public class SortableTableExample extends JPanel {
 
  public SortableTableExample(){
    setLayout(new BorderLayout());
    String[] headerStr = {"Name","Date","Size","Dir"};
    int[] columnWidth = {100,150,100,50};
    
    SortableTableModel dm = new SortableTableModel() {
      public Class getColumnClass(int col) {
        switch (col) {
          case  0: return String.class;
          case  1: return Date.class;
          case  2: return Integer.class;
          case  3: return Boolean.class;
          default: return Object.class;
        }
      }
      public boolean isCellEditable(int row, int col) {
        switch (col) {
          case  1: return false;
          default: return true;
        }
      }  
      public void setValueAt(Object obj, int row, int col) {
        switch (col) {
          case  2: super.setValueAt(new Integer(obj.toString()), row, col); return;
          default: super.setValueAt(obj, row, col); return;
        }
      }
    };
    dm.setDataVector(new Object[][]{
      {"b"   ,getDate("98/12/02"),new Integer(14),new Boolean(false)},
      {"a"   ,getDate("99/01/01"),new Integer(67),new Boolean(false)},
      {"d"   ,getDate("99/02/11"),new Integer(2) ,new Boolean(false)},
      {"c"   ,getDate("99/02/27"),new Integer(7) ,new Boolean(false)},
      {"foo" ,new Date()         ,new Integer(5) ,new Boolean(true)},
      {"bar" ,new Date()         ,new Integer(10),new Boolean(true)}},
      headerStr);
     
    JTable table = new JTable(dm);
    //table.setShowGrid(false);
    table.setShowVerticalLines(true);
    table.setShowHorizontalLines(false);
    SortButtonRenderer renderer = new SortButtonRenderer();
    TableColumnModel model = table.getColumnModel();
    int n = headerStr.length;
    for (int i=0;i<n;i++) {
      model.getColumn(i).setHeaderRenderer(renderer);
      model.getColumn(i).setPreferredWidth(columnWidth[i]);
    }
    
    JTableHeader header = table.getTableHeader();
    header.addMouseListener(new HeaderListener(header,renderer));
    JScrollPane pane = new JScrollPane(table);
    add(pane, BorderLayout.CENTER);
  }
 
  public static void main(String[] args) {
    JFrame f= new JFrame("SortableTable Example");
    f.getContentPane().add(new SortableTableExample(), BorderLayout.CENTER);
    f.setSize(400, 160);
    f.setVisible(true);
    f.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {System.exit(0);}
    });
  }
  
  private static DateFormat dateFormat = 
    DateFormat.getDateInstance(DateFormat.SHORT, Locale.JAPAN);
 
  private static Date getDate(String dateString) {
    Date date = null;
    try {
      date = dateFormat.parse(dateString);
    } catch(ParseException ex) {
      date = new Date();
    }
    return date;
  }
 
  class HeaderListener extends MouseAdapter {
    JTableHeader   header;
    SortButtonRenderer renderer;
  
    HeaderListener(JTableHeader header,SortButtonRenderer renderer) {
      this.header   = header;
      this.renderer = renderer;
    }
  
    public void mousePressed(MouseEvent e) {
      int col = header.columnAtPoint(e.getPoint());
      int sortCol = header.getTable().convertColumnIndexToModel(col);
      renderer.setPressedColumn(col);
      renderer.setSelectedColumn(col);
      header.repaint();
      
      if (header.getTable().isEditing()) {
        header.getTable().getCellEditor().stopCellEditing();
      }
      
      boolean isAscent;
      if (SortButtonRenderer.DOWN == renderer.getState(col)) {
        isAscent = true;
      } else {
        isAscent = false;
      }
      ((SortableTableModel)header.getTable().getModel())
        .sortByColumn(sortCol, isAscent);    
    }
  
    public void mouseReleased(MouseEvent e) {
      int col = header.columnAtPoint(e.getPoint());
      renderer.setPressedColumn(-1);                // clear
      header.repaint();
    }
  }
}

SortableTableModel.java:

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
 
/**
 * @version 1.0 02/25/99
 */
public class SortableTableModel extends DefaultTableModel {
  int[] indexes;
  TableSorter sorter;
 
  public SortableTableModel() {   
  }
    
  public Object getValueAt(int row, int col) {
    int rowIndex = row;
    if (indexes != null) {
      rowIndex = indexes[row];
    }
    return super.getValueAt(rowIndex, col);
  }
    
  public void setValueAt(Object value, int row, int col) {    
    int rowIndex = row;
    if (indexes != null) {
      rowIndex = indexes[row];
    }
    super.setValueAt(value, rowIndex, col);
  }
  
 
  public void sortByColumn(int column, boolean isAscent) {
    if (sorter == null) {
      sorter = new TableSorter(this);
    }   
    sorter.sort(column, isAscent);   
    fireTableDataChanged();
  }
  
  public int[] getIndexes() {
    int n = getRowCount();
    if (indexes != null) {
      if (indexes.length == n) {
        return indexes;
      }
    }
    indexes = new int[n];
    for (int i=0; i<n; i++) {
      indexes[i] = i;
    }
    return indexes;
  }
}

TableSorter.java:

import java.awt.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
 
/**
 * @version 1.0 02/25/99
 */
public class TableSorter {
  SortableTableModel model;
 
  public TableSorter(SortableTableModel model) {
    this.model = model;
  }
  
  
  //n2 selection
  public void sort(int column, boolean isAscent) {   
    int n = model.getRowCount();
    int[] indexes = model.getIndexes();   
    
    for (int i=0; i<n-1; i++) {
      int k = i;
      for (int j=i+1; j<n; j++) {
        if (isAscent) {
          if (compare(column, j, k) < 0) {
            k = j;
          }
        } else {
          if (compare(column, j, k) > 0) {
            k = j;
          }
        }
      }
      int tmp = indexes[i];
      indexes[i] = indexes[k];
      indexes[k] = tmp;
    }
  }
    
 
  // comparaters
  
  public int compare(int column, int row1, int row2) {
    Object o1 = model.getValueAt(row1, column);
    Object o2 = model.getValueAt(row2, column); 
    if (o1 == null && o2 == null) {
      return  0; 
    } else if (o1 == null) {
      return -1; 
    } else if (o2 == null) { 
      return  1; 
    } else {   
      Class type = model.getColumnClass(column);
      if (type.getSuperclass() == Number.class) {
        return compare((Number)o1, (Number)o2);
      } else if (type == String.class) {
        return ((String)o1).compareTo((String)o2);
      } else if (type == Date.class) {
        return compare((Date)o1, (Date)o2);
      } else if (type == Boolean.class) {
        return compare((Boolean)o1, (Boolean)o2);
      } else {
        return ((String)o1).compareTo((String)o2);
      }      
    }
  }
  
  public int compare(Number o1, Number o2) {
    double n1 = o1.doubleValue();
    double n2 = o2.doubleValue();
    if (n1 < n2) {
      return -1;
    } else if (n1 > n2) {
      return 1;
    } else {
      return 0;
    }
  }
  
  public int compare(Date o1, Date o2) {
    long n1 = o1.getTime();
    long n2 = o2.getTime();
    if (n1 < n2) {
      return -1;
    } else if (n1 > n2) {
      return 1;
    } else {
      return 0;
    }
  }
  
  public int compare(Boolean o1, Boolean o2) {
    boolean b1 = o1.booleanValue();
    boolean b2 = o2.booleanValue();
    if (b1 == b2) {
      return 0;
    } else if (b1) {
      return 1;
    } else {
      return -1;
    }
  }
}

SortButtonRenderer.java:

import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
 
/**
 * @version 1.0 02/25/99
 */
public class SortButtonRenderer extends JButton implements TableCellRenderer {
  public static final int NONE = 0;
  public static final int DOWN = 1;
  public static final int UP   = 2;
  
  int pushedColumn;
  Hashtable state;
  JButton downButton,upButton;
  
  public SortButtonRenderer() {
    pushedColumn   = -1;
    state = new Hashtable();
    
    setMargin(new Insets(0,0,0,0));
    setHorizontalTextPosition(LEFT);
    setIcon(new BlankIcon());
    
    // perplexed  
    // ArrowIcon(SwingConstants.SOUTH, true)   
    // BevelArrowIcon (int direction, boolean isRaisedView, boolean isPressedView)
    
    downButton = new JButton();
    downButton.setMargin(new Insets(0,0,0,0));
    downButton.setHorizontalTextPosition(LEFT);
    downButton.setIcon(new BevelArrowIcon(BevelArrowIcon.DOWN, false, false));
    downButton.setPressedIcon(new BevelArrowIcon(BevelArrowIcon.DOWN, false, true));
    
    upButton = new JButton();
    upButton.setMargin(new Insets(0,0,0,0));
    upButton.setHorizontalTextPosition(LEFT);
    upButton.setIcon(new BevelArrowIcon(BevelArrowIcon.UP, false, false));
    upButton.setPressedIcon(new BevelArrowIcon(BevelArrowIcon.UP, false, true));
    
  }
  
  public Component getTableCellRendererComponent(JTable table, Object value,
                   boolean isSelected, boolean hasFocus, int row, int column) {
    JButton button = this;
    Object obj = state.get(new Integer(column));
    if (obj != null) {
      if (((Integer)obj).intValue() == DOWN) {
        button = downButton;
      } else {
        button = upButton;
      }
    }
    button.setText((value ==null) ? "" : value.toString());
    boolean isPressed = (column == pushedColumn);
    button.getModel().setPressed(isPressed);
    button.getModel().setArmed(isPressed);
    return button;
  }
  
  public void setPressedColumn(int col) {
    pushedColumn = col;
  }
  
  public void setSelectedColumn(int col) {
    if (col < 0) return;
    Integer value = null;
    Object obj = state.get(new Integer(col));
    if (obj == null) {
      value = new Integer(DOWN);
    } else {
      if (((Integer)obj).intValue() == DOWN) {
        value = new Integer(UP);
      } else {
        value = new Integer(DOWN);
      }
    }
    state.clear();
    state.put(new Integer(col), value);
  } 
  
  public int getState(int col) {
    int retValue;
    Object obj = state.get(new Integer(col));
    if (obj == null) {
      retValue = NONE;
    } else {
      if (((Integer)obj).intValue() == DOWN) {
        retValue = DOWN;
      } else {
        retValue = UP;
      }
    }
    return retValue;
  } 
}

BevelArrowIcon.java:

import java.awt.*;
import javax.swing.*;
 
/**
 * @version 1.0 02/26/99
 */
public class BevelArrowIcon implements Icon {
  public static final int UP    = 0;         // direction
  public static final int DOWN  = 1;
   
  private static final int DEFAULT_SIZE = 11;
 
  private Color edge1;
  private Color edge2;
  private Color fill;
  private int size;
  private int direction;
 
  public BevelArrowIcon(int direction, boolean isRaisedView, boolean isPressedView) {
    if (isRaisedView) {
      if (isPressedView) {
        init( UIManager.getColor("controlLtHighlight"),
              UIManager.getColor("controlDkShadow"),
              UIManager.getColor("controlShadow"),
              DEFAULT_SIZE, direction);
      } else {
        init( UIManager.getColor("controlHighlight"),
              UIManager.getColor("controlShadow"),
              UIManager.getColor("control"),
              DEFAULT_SIZE, direction);
      }
    } else {
      if (isPressedView) {
        init( UIManager.getColor("controlDkShadow"),
              UIManager.getColor("controlLtHighlight"),
              UIManager.getColor("controlShadow"),
              DEFAULT_SIZE, direction);
      } else {
        init( UIManager.getColor("controlShadow"),
              UIManager.getColor("controlHighlight"),
              UIManager.getColor("control"),
              DEFAULT_SIZE, direction);
      }
    }
  }
 
  public BevelArrowIcon(Color edge1, Color edge2, Color fill,
                   int size, int direction) {
    init(edge1, edge2, fill, size, direction);
  }
 
  public void paintIcon(Component c, Graphics g, int x, int y) {
    switch (direction) {
      case DOWN: drawDownArrow(g, x, y); break;
      case   UP: drawUpArrow(g, x, y);   break;
    }
  } 
 
  public int getIconWidth() {
    return size;
  }
 
  public int getIconHeight() {
    return size;
  }
 
 
  private void init(Color edge1, Color edge2, Color fill,
                   int size, int direction) {
    this.edge1 = edge1;
    this.edge2 = edge2;
    this.fill = fill;
    this.size = size;
    this.direction = direction;
  }
 
  private void drawDownArrow(Graphics g, int xo, int yo) {
    g.setColor(edge1);
    g.drawLine(xo, yo,   xo+size-1, yo);
    g.drawLine(xo, yo+1, xo+size-3, yo+1);
    g.setColor(edge2);
    g.drawLine(xo+size-2, yo+1, xo+size-1, yo+1);
    int x = xo+1;
    int y = yo+2;
    int dx = size-6;      
    while (y+1 < yo+size) {
      g.setColor(edge1);
      g.drawLine(x, y,   x+1, y);
      g.drawLine(x, y+1, x+1, y+1);
      if (0 < dx) {
        g.setColor(fill);
        g.drawLine(x+2, y,   x+1+dx, y);
        g.drawLine(x+2, y+1, x+1+dx, y+1);
      }
      g.setColor(edge2);
      g.drawLine(x+dx+2, y,   x+dx+3, y);
      g.drawLine(x+dx+2, y+1, x+dx+3, y+1);
      x += 1;
      y += 2;
      dx -= 2;     
    }
    g.setColor(edge1);
    g.drawLine(xo+(size/2), yo+size-1, xo+(size/2), yo+size-1); 
  }
 
  private void drawUpArrow(Graphics g, int xo, int yo) {
    g.setColor(edge1);
    int x = xo+(size/2);
    g.drawLine(x, yo, x, yo); 
    x--;
    int y = yo+1;
    int dx = 0;
    while (y+3 < yo+size) {
      g.setColor(edge1);
      g.drawLine(x, y,   x+1, y);
      g.drawLine(x, y+1, x+1, y+1);
      if (0 < dx) {
        g.setColor(fill);
        g.drawLine(x+2, y,   x+1+dx, y);
        g.drawLine(x+2, y+1, x+1+dx, y+1);
      }
      g.setColor(edge2);
      g.drawLine(x+dx+2, y,   x+dx+3, y);
      g.drawLine(x+dx+2, y+1, x+dx+3, y+1);
      x -= 1;
      y += 2;
      dx += 2;     
    }
    g.setColor(edge1);
    g.drawLine(xo, yo+size-3,   xo+1, yo+size-3);
    g.setColor(edge2);
    g.drawLine(xo+2, yo+size-2, xo+size-1, yo+size-2);
    g.drawLine(xo, yo+size-1, xo+size, yo+size-1);
  }
}

BlankIcon.java:

import java.awt. *;
import javax.swing. *;
 
/**
 * @version 1.0 02/26/99
 */
public class BlankIcon implements Icon {
  private Color fillColor;
  private int size;
 
  public BlankIcon() {
    this(null, 11);
  }
 
  public BlankIcon(Color color, int size) {
    //UIManager.getColor("control")
    //UIManager.getColor("controlShadow")
    fillColor = color;
 
    this.size = size;    
  }
 
  public void paintIcon(Component c, Graphics g, int x, int y) {
    if (fillColor != null) {
      g.setColor(fillColor);
      g.drawRect(x, y, size-1, size-1);
    }
  }
 
  public int getIconWidth() {
    return size;
  }
 
  public int getIconHeight() {
    return size;
  }
}

Creating a JTable with pushable headers

Courtesy of Nobuo Tamemasa (http://www2.gol.com/users/tame/swing/examples/JTableExamples5.html)



PushableHeaderExample.java:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
 
/**
 * @version 1.0 02/25/99
 */
public class PushableHeaderExample extends JPanel {

  public PushableHeaderExample(){
    setLayout(new BorderLayout());
    String[] headerStr = {"Push","me","here"};
    
    DefaultTableModel dm = new DefaultTableModel(headerStr, 4);
    JTable table = new JTable(dm);
    ButtonHeaderRenderer renderer = new ButtonHeaderRenderer();
    TableColumnModel model = table.getColumnModel();
    int n = headerStr.length;
    for (int i=0;i<n;i++) {
      model.getColumn(i).setHeaderRenderer(renderer);
    }
    
    JTableHeader header = table.getTableHeader();
    header.addMouseListener(new HeaderListener(header,renderer));
    JScrollPane pane = new JScrollPane(table);
    add(pane, BorderLayout.CENTER);
  }

  public static void main(String[] args) {
    JFrame f= new JFrame("PushableHeaderTable Example");
    f.getContentPane().add(new PushableHeaderExample(), BorderLayout.CENTER);
    f.setSize(400, 100);
    f.setVisible(true);
    f.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {System.exit(0);}
    });
  }

  class HeaderListener extends MouseAdapter {
    JTableHeader   header;
    ButtonHeaderRenderer renderer;
  
    HeaderListener(JTableHeader header,ButtonHeaderRenderer renderer) {
      this.header   = header;
      this.renderer = renderer;
    }
  
    public void mousePressed(MouseEvent e) {
      int col = header.columnAtPoint(e.getPoint());
      renderer.setPressedColumn(col);
      header.repaint();
      
      System.out.println("Ouch! " + col);
    }
  
    public void mouseReleased(MouseEvent e) {
      int col = header.columnAtPoint(e.getPoint());
      renderer.setPressedColumn(-1);                // clear
      header.repaint();
    }
  }
    
  class ButtonHeaderRenderer extends JButton implements TableCellRenderer {
    int pushedColumn;
  
    public ButtonHeaderRenderer() {
      pushedColumn   = -1;
      setMargin(new Insets(0,0,0,0));
    }
  
    public Component getTableCellRendererComponent(JTable table, Object value,
                   boolean isSelected, boolean hasFocus, int row, int column) {
      setText((value ==null) ? "" : value.toString());
      boolean isPressed = (column == pushedColumn);
      getModel().setPressed(isPressed);
      getModel().setArmed(isPressed);
      return this;
    }
  
    public void setPressedColumn(int col) {
      pushedColumn = col;
    }
  }
}

Programmatically selecting a JTable cell

Use setRowSelectionInterval and setColumnSelectionInterval.

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame 
{
   public Main() {
      super("Table example, Wines from Bordeaux");
 
      Object[][] tabledata = {
            { "Chateau Meyney, St. Estephe", 	   new Integer(1994), "$18.75"},
            { "Chateau Montrose, St. Estephe", 	   new Integer(1975), "$54.25" },
            { "Chateau Gloria, St. Julien", 	   new Integer(1993), "$22.99" },
            { "Chateau Beychevelle, St. Julien",   new Integer(1970), "$61.63" },
            { "Chateau La Tour de Mons, Margeaux", new Integer(1975), "$57.03" },
            { "Chateau Brane-Cantenac, Margeaux",  new Integer(1978), "$49.92" },
      };
 
      String columnheaders[] = { "Wine", "Vintage", "Price" };
 
      JTable table = new JTable(tabledata, columnheaders);
      table.setPreferredScrollableViewportSize(new Dimension(500, 70));
      JScrollPane scrollPane = new JScrollPane(table);
 
      getContentPane().add(scrollPane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      // programmatically select rows
      table.setRowSelectionInterval(1, 2);
      table.setColumnSelectionInterval(1, 2);
 
      pack();
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
}

Have dotted lines in a JTree

That appends on your Look & Feel – you can use three lineStyle’s:

// show hierarchy-lines
JTree#putClientProperty(“JTree.lineStyle”, “Angled”);

// show horizontal lines
JTree#putClientProperty( “JTree.lineStyle”, “Horitontal” );

// do not show any lines
JTree#putClientProperty(“JTree.lineStyle”, “None”);

Having a JTextArea as a node of a JTree

Main.java:

import javax.swing.border.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.net.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = createNodes();
      JTree tree = new JTree(root);
      //tree.setCellEditor(new DefaultCellEditor(new JTextField())); 
      tree.setCellRenderer(new DelegateDefaultCellRenderer());
      tree.setRowHeight(-1);
 
      getContentPane().add(new JScrollPane(tree));
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode(&amp;amp;quot;Java&amp;amp;quot;);
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode(&amp;amp;quot;J2SE&amp;amp;quot;);
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode(&amp;amp;quot;J2EE&amp;amp;quot;);
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode(&amp;amp;quot;J2ME&amp;amp;quot;);
 
      j2se.add(new DefaultMutableTreeNode(&amp;amp;quot;http://java.sun.com/j2se/&amp;amp;quot;));
      j2ee.add(new DefaultMutableTreeNode(&amp;amp;quot;http://java.sun.com/j2ee/&amp;amp;quot;));
      j2me.add(new DefaultMutableTreeNode(&amp;amp;quot;http://java.sun.com/j2me/&amp;amp;quot;));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}
 
class DelegateDefaultCellRenderer extends DefaultTreeCellRenderer 
{
   TextAreaRenderer taRenderer = new TextAreaRenderer();
 
   public DelegateDefaultCellRenderer() {
      taRenderer.setBackgroundNonSelectionColor(getBackgroundNonSelectionColor());
      taRenderer.setBackgroundSelectionColor(getBackgroundSelectionColor());
      taRenderer.setTextNonSelectionColor(getTextNonSelectionColor());  
      taRenderer.setTextSelectionColor(getTextSelectionColor()); 
   }
 
   public Component getTreeCellRendererComponent(JTree tree, Object value,
                                  boolean selected, boolean expanded, boolean leaf,
                                  int row, boolean hasFocus)
   {
      if (!leaf) {
         return super.getTreeCellRendererComponent(tree, value, selected, 
                                                   expanded, leaf, row, hasFocus);
      }
      else {
         return taRenderer.getTreeCellRendererComponent(tree, value, selected, 
                                                        expanded, leaf, row, hasFocus);
      }
   }
}   
 
class TextAreaRenderer extends JScrollPane implements TreeCellRenderer
{
   JTextArea textarea;
   Color backgroundNonSelectionColor;
   Color backgroundSelectionColor;
   Color textNonSelectionColor;
   Color textSelectionColor;
 
   public TextAreaRenderer() {
      textarea = new JTextArea(3, 40);
      textarea.setLineWrap(true);
      textarea.setWrapStyleWord(true);
      textarea.setBorder(new TitledBorder(&amp;amp;quot;This is a JTextArea&amp;amp;quot;));
      getViewport().add(textarea);
   }
 
   public void setBackgroundNonSelectionColor(Color c) {
      this.backgroundNonSelectionColor = c;
   }
 
   public void setBackgroundSelectionColor(Color c) {
      this.backgroundSelectionColor = c;
   }
  
   public void setTextNonSelectionColor(Color c) {
      this.textNonSelectionColor = c;
   }
  
   public void setTextSelectionColor(Color c) {
      this.textSelectionColor = c;
   }
 
   public Component getTreeCellRendererComponent(JTree tree, Object value,
                                  boolean selected, boolean expanded, boolean leaf,
                                  int row, boolean hasFocus)
   {
      if (selected) {
         setForeground(textSelectionColor);
         setBackground(backgroundSelectionColor);
         textarea.setForeground(textSelectionColor);
         textarea.setBackground(backgroundSelectionColor);
      } else {
         setForeground(textNonSelectionColor);
         setBackground(backgroundNonSelectionColor);
         textarea.setForeground(textNonSelectionColor);
         textarea.setBackground(backgroundNonSelectionColor);
      }
 
      textarea.setText(&amp;amp;quot;&amp;amp;quot;+((DefaultMutableTreeNode) value).getUserObject()); 
      textarea.setCaretPosition(0);
 
      return this;
   }
}

Don’t change filename textfield when a directory is selected in a JFileChooser

Here’s some code that solves that problem.

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
import java.io.*;
 
public class Main extends JFrame
{
   private String fileSelected = "autoexec.bat";
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
  
   public Main() {
      JButton fileButton = new JButton("Select File");
      fileButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            File file = getFileFromUser();
            if (file != null)
               System.out.println(file.getName());
         }
      });
      getContentPane().add(fileButton);
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
 
      pack();
   }
  
   public File getFileFromUser() {
      JFileChooser fc = new JFileChooser();
 
      // use current directory
      fc.setCurrentDirectory(new File("c:\"));
 
      // set default name
      fc.setSelectedFile(new File(fileSelected));
 
      fc.addPropertyChangeListener(new PropertyChangeListener() {
         public void propertyChange(PropertyChangeEvent pce) {
            String property = pce.getPropertyName();
            if (property.equals(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)) {
               File dir = (File) pce.getNewValue();
               if (dir.isDirectory()) {
                  ((JFileChooser) pce.getSource()).setSelectedFile(new File(dir, fileSelected));
               }
               else {
                  fileSelected = ((JFileChooser) pce.getSource()).getSelectedFile().getName();
               }
            }
            else if (property.equals(JFileChooser.DIRECTORY_CHANGED_PROPERTY)) {
               File dir = (File) pce.getNewValue();
               ((JFileChooser) pce.getSource()).setSelectedFile(new File(dir, fileSelected));
            }
         }
      });
 
      // show dialog for opening files
      int result = fc.showSaveDialog(this);
 
      if (result != fc.APPROVE_OPTION) 
         return null;
       
      return fc.getSelectedFile();
   }
}

Have two JTrees vertically aligned in a JScrollPane

Main.java:

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = createNodes();
      JTree tree1 = new JTree(root);
      JTree tree2 = new JTree(root);
 
      tree1.addTreeSelectionListener(new TreeSelectionListener() {
         public void valueChanged(TreeSelectionEvent e) {         
            TreePath path = e.getPath();
            System.out.println(path.getLastPathComponent());     
         }
      });
 
      tree2.addTreeSelectionListener(new TreeSelectionListener() {
         public void valueChanged(TreeSelectionEvent e) {         
            TreePath path = e.getPath();
            System.out.println(path.getLastPathComponent());     
         }
      });
  
      Box box = Box.createVerticalBox();
      box.add(tree1);
      box.add(tree2);
 
      // bugparade #4833645
      tree1.setMinimumSize(tree1.getPreferredSize());
      tree1.setAlignmentX(0);
      tree2.setMinimumSize(tree2.getPreferredSize());
      tree2.setAlignmentX(0);
 
      getContentPane().setLayout(new BorderLayout());
     
      JScrollPane sp = new JScrollPane(box);
      sp.getViewport().setBackground(Color.white);
 
      getContentPane().add(BorderLayout.NORTH, sp);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
  
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Java");
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode("J2SE");
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode("J2EE");
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode("J2ME");
 
      j2se.add(new DefaultMutableTreeNode("http://java.sun.com/j2se/"));
      j2ee.add(new DefaultMutableTreeNode("http://java.sun.com/j2ee/"));
      j2me.add(new DefaultMutableTreeNode("http://java.sun.com/j2me/"));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}