Re: Drag lables/button on

  To: comp.lang.java.gui

Chanchal wrote:


import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.*;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.event.MouseInputAdapter;

public class LabelTest
{
  private JFrame frame;
  private GraphicPanel graphicPanel;
  private JPanel controlPanel;
  private JPanel buttonPanel;
  private JPanel linePanel;
  private JButton addButton;
  private JButton removeButton;
  private JButton addLine;
  private JButton removeLine;
  private JButton lineSelectionSource;
  private JButton lineSelectionDestination;
  private JTextField message;
  private boolean isAddingLine = true;
  private boolean isRemovingButton = false;
  private boolean inLineSelection = false;
  private ActionListener actionHandler;
  private MouseMotionHandler mouseMotionHandler;
  private MouseHandler mouseHandler;
  private String defaultMessage;

  LabelTest()
  {
    actionHandler = new ActionHandler();
    mouseMotionHandler = new MouseMotionHandler();
    mouseHandler = new MouseHandler();
    frame = new JFrame("LabelTest");
    graphicPanel = new GraphicPanel();
    controlPanel = new JPanel(new BorderLayout());
    buttonPanel = new JPanel();
    linePanel = new JPanel();
    addButton = new JButton("Add Button");
    removeButton = new JButton("Remove Button");
    addLine = new JButton("Add Line");
    removeLine = new JButton("Remove Line");
    lineSelectionSource = null;
    lineSelectionDestination = null;
    defaultMessage = "Add a couple Buttons.";
    message = new JTextField(defaultMessage);

    buttonPanel.add(addButton);
    buttonPanel.add(removeButton);
    linePanel.add(addLine);
    linePanel.add(removeLine);
    controlPanel.add(buttonPanel, BorderLayout.NORTH);
    controlPanel.add(linePanel, BorderLayout.SOUTH);

    frame.setSize(600, 480);
    frame.setLayout(new BorderLayout());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(message, BorderLayout.SOUTH);
    frame.add(graphicPanel, BorderLayout.CENTER);
    frame.add(controlPanel, BorderLayout.NORTH);

    graphicPanel.setLayout(null);
    graphicPanel.setBorder(BorderFactory.
        createLineBorder(Color.GRAY));
    controlPanel.setBorder(BorderFactory.
        createLoweredBevelBorder());
    // thanks to Michael Dunn for rescue here
    graphicPanel.setPreferredSize(new Dimension(600, 350));

    addButton.addActionListener(actionHandler);
    removeButton.addActionListener(actionHandler);
    addLine.addActionListener(actionHandler);
    removeLine.addActionListener(actionHandler);

    frame.setVisible(true);
  }

  class MouseMotionHandler
  extends MouseMotionAdapter
  {
    public void mouseDragged(MouseEvent e)
    {
      Component c = e.getComponent();
      c.setLocation(c.getX() + e.getX(),
          c.getY() + e.getY());
      graphicPanel.repaint();
    }
  }

  class MouseHandler extends MouseInputAdapter
  {
    public void mouseClicked(MouseEvent e)
    {
      if (e.getSource() instanceof
          JButton && isRemovingButton == true)
      {
        graphicPanel.removeButton(
            (JButton) e.getSource());
        message.setText(defaultMessage);
      }
      else if (e.getSource() instanceof JButton
          && inLineSelection == true
          && lineSelectionSource == null)
      {
        lineSelectionSource = (JButton) e.getSource();
        message.setText("Select Destination Button");
      }
      else if (e.getSource() instanceof
          JButton && inLineSelection == true
          && lineSelectionSource != null)
      {
        lineSelectionDestination = (JButton) e.getSource();
        if (isAddingLine == true)
        {
          graphicPanel.addLine();
        }
        else if (isAddingLine == false)
        {
          graphicPanel.removeLine();
        }
      }
    }
  }

  class ActionHandler implements ActionListener
  {

    public void actionPerformed(ActionEvent e)
    {
      if (e.getSource().equals(addButton))
      {
        graphicPanel.addButton();
      }
      else if (e.getSource().equals(removeButton))
      {
        isRemovingButton = true;
        message.setText(("Select Button to remove."));
      }
      else if (e.getSource().equals(addLine))
      {
        inLineSelection = true;
        isAddingLine = true;
        message.setText(("Select Source Button."));
      }
      else if (e.getSource().equals(removeLine))
      {
        inLineSelection = true;
        isAddingLine = false;
        message.setText(("Select Source Button."));
      }
    }
  }

  class Line
  {
    private JButton source;
    private JButton destination;

    public boolean isValid()
    {
      if (null != source && null != destination)
        return true;
      else
        return false;
    }

    JButton getSourceButton()
    { return source; }

    JButton getDestinationButton()
    { return destination; }

    Point getSourceLocation()
    {
      Point p = source.getLocation();
      Dimension d = source.getSize();
      p.x = d.width / 2 + p.x;
      p.y = d.height / 2 + p.y;
      return p;
    }

    Point getDestinationLocation()
    {
      Point p = destination.getLocation();
      Dimension d = destination.getSize();
      p.x = d.width / 2 + p.x;
      p.y = d.height / 2 + p.y;
      return p;
    }

    public void setSource(JButton b)
    { source = b; }

    public void setDestination(JButton b)
    { destination = b; }
  }

  @SuppressWarnings("serial")
  class GraphicPanel extends JPanel
  {
    Set<Line> lineSet = new HashSet<Line>();
    int buttonCount = 0;

    protected void paintComponent(Graphics g)
    {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      for (Line l : lineSet)
      {
        g2.drawLine(l.getSourceLocation().x,
            l.getSourceLocation().y, l
            .getDestinationLocation().x,
            l.getDestinationLocation().y);
      }
    }

    private void setDefaultMessage()
    {
      if(buttonCount == 0)
        defaultMessage = "Add a couple Buttons.";
      else if(buttonCount == 1)
        defaultMessage = "Move Button and add another.";
      else defaultMessage =
        "Add, Remove or Move Button, or Add, Remove Line.";
    }

    public void addButton()
    {
      JButton b = new JButton(" ");
      b.addMouseListener(mouseHandler);
      b.addMouseMotionListener(mouseMotionHandler);
      Point p = new Point(getBounds()
          .width / 2, getBounds().height / 2);
      b.setBounds(p.x, p.y, b.getPreferredSize().width,
          b.getPreferredSize().height);
      add(b);
      buttonCount++;
      setDefaultMessage();
      message.setText(defaultMessage);
      validate();
      repaint();
    }

    public void removeButton(JButton b)
    {
      removeLines(b);
      remove(b);
      buttonCount--;
      setDefaultMessage();
      message.setText(defaultMessage);
      isRemovingButton = false;
      validate();
      repaint();
    }

    public void addLine()
    {
      Line l = new Line();
      if (lineSelectionSource != null &&
          lineSelectionDestination != null)
      {
        l.setSource(lineSelectionSource);
        l.setDestination(lineSelectionDestination);
        lineSet.add(l);
      }
      lineSelectionSource = null;
      lineSelectionDestination = null;
      message.setText(defaultMessage);
      repaint();
    }

    public void removeLine()
    {
      Line l = new Line();
      Iterator it = lineSet.iterator();
      if (lineSelectionSource != null &&
          lineSelectionDestination != null)
      {
        while (it.hasNext())
        {
          l = (Line) it.next();
          if (
            (l.getSourceButton()
              .equals(lineSelectionSource)
            && l.getDestinationButton()
              .equals(lineSelectionDestination))
            ||
            (l.getSourceButton()
              .equals(lineSelectionDestination)
            && l.getDestinationButton()
              .equals(lineSelectionSource)))
          {
            lineSet.remove(l);
            break;
          }
        }
        lineSelectionSource = null;
        lineSelectionDestination = null;
        message.setText(defaultMessage);
        repaint();
      }
    }

    public void removeLines(JButton b)
    {
      Set<Line> removalSet = new HashSet<Line>();
      Iterator it = lineSet.iterator();
      Line l;
      while (it.hasNext())
      {
        l = (Line) it.next();
        if (l.source.equals(b) || l.destination.equals(b))
          removalSet.add(l);
      }
      for(Line r : removalSet)
      { lineSet.remove(r); }
      repaint();
    }
  }

  public static void main(String[] args)
  {
    @SuppressWarnings("unused")
    LabelTest test = new LabelTest();
  }
}

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