Thread: keylistener small problem

Originally Posted by matecno

Hello,

I wrote this simple and neat code and implemented a mouselistener and a keylistener, but for reason or another the keylistener is not doing its job...can anyone help please?

package chapter2;
 
import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
 
public class DrawShapes extends JApplet implements ActionListener {
  public static void main(String s[]) {
    JFrame frame = new JFrame();
    frame.setTitle("Drawing Geometric Shapes");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JApplet applet = new DrawShapes();
    applet.init();
    frame.getContentPane().add(applet);
    frame.pack();
    frame.setVisible(true);
 
  }
 
  JavaDraw2DPanel panel = null;
 
 
  public void init() {
    JMenuBar mb = new JMenuBar();
    setJMenuBar(mb);
    JMenu menu = new JMenu("Objects");
    mb.add(menu);
    JMenuItem mi = new JMenuItem("Rectangle");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("RoundRectangle");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("Ellipse");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("Arc");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("Line");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("QuadCurve");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("CubicCurve");
    mi.addActionListener(this);
    menu.add(mi);
    mi = new JMenuItem("Polygon");
    mi.addActionListener(this);
    menu.add(mi);
    panel = new JavaDraw2DPanel();
    getContentPane().add(panel);
 
 
  }
 
  public void actionPerformed(ActionEvent ev) {
 
    String command = ev.getActionCommand();
    if ("Rectangle".equals(command)) {
      panel.shapeType = panel.RECTANGLE;
    } else if ("RoundRectangle".equals(command)) {
      panel.shapeType = panel.ROUNDRECTANGLE2D;
    } else if ("Ellipse".equals(command)) {
      panel.shapeType = panel.ELLIPSE2D;
    } else if ("Arc".equals(command)) {
      panel.shapeType = panel.ARC2D;
    } else if ("Line".equals(command)) {
      panel.shapeType = panel.LINE2D;
    } else if ("QuadCurve".equals(command)) {
      panel.shapeType = panel.QUADCURVE2D;
    } else if ("CubicCurve".equals(command)) {
      panel.shapeType = panel.CUBICCURVE2D;
    } else if ("Polygon".equals(command)) {
      panel.shapeType = panel.POLYGON;
    }
  }
 
 
 
}

class JavaDraw2DPanel extends JPanel implements MouseListener, MouseMotionListener, KeyListener{
  private Vector shapes = new Vector();
  static final int RECTANGLE = 0;
  static final int ROUNDRECTANGLE2D = 1;
  static final int ELLIPSE2D = 2;
  static final int ARC2D = 3;
  static final int LINE2D = 4;
  static final int QUADCURVE2D = 5;
  static final int CUBICCURVE2D = 6;
  static final int POLYGON = 7;
  static final int GENERAL = 8;
  static final int AREA = 9;
 
 
  int shapeType = RECTANGLE;
  // vector of input points
  Vector points = new Vector();
  int pointIndex = 0;
  Shape partialShape = null;
  Point p = null;
 
  public JavaDraw2DPanel() {
    super();
    setBackground(Color.white);
    setPreferredSize(new Dimension(640, 480));
    addKeyListener(this);
    addMouseListener(this);
    addMouseMotionListener(this);
  }
 
  public void paintComponent(Graphics g) {
 
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    for (int i = 0; i < shapes.size(); i++) {
      Shape s = (Shape)shapes.get(i);
      g2.draw(s);
    }
  }
 
 
 
 
 
 
  public void mouseClicked(MouseEvent ev) {
  }
 
  public void mouseEntered(MouseEvent ev) {
  }
 
  public void mouseExited(MouseEvent ev) {
  }
 
  public void mousePressed(MouseEvent ev) {
    points.add(ev.getPoint());
    pointIndex++;
    p = null;
  }
 
  public void mouseReleased(MouseEvent ev) {
  }
 
  public void mouseMoved(MouseEvent ev) {
  }
 
  public void mouseDragged(MouseEvent ev) {
    Graphics2D g = (Graphics2D)getGraphics();
    g.setXORMode(Color.white);
    Point p1 = (Point)points.get(pointIndex-1);
    switch (shapeType) {
      case RECTANGLE:
        if (p != null) g.drawRect(p1.x, p1.y, p.x-p1.x, p.y-p1.y);
        p = ev.getPoint();
        g.drawRect(p1.x, p1.y, p.x-p1.x, p.y-p1.y);
        break;
      case ROUNDRECTANGLE2D:
        if (p != null) g.drawRoundRect(p1.x, p1.y, p.x-p1.x, p.y-p1.y,10,10);
        p = ev.getPoint();
        g.drawRoundRect(p1.x, p1.y, p.x-p1.x, p.y-p1.y,10,10);
        break;
      case ELLIPSE2D:
        if (p != null) g.drawOval(p1.x, p1.y, p.x-p1.x, p.y-p1.y);
        p = ev.getPoint();
        g.drawOval(p1.x, p1.y, p.x-p1.x, p.y-p1.y);
        break;
      case ARC2D:
        if (p != null) g.drawArc(p1.x, p1.y, p.x-p1.x, p.y-p1.y, 30, 120);
        p = ev.getPoint();
        g.drawArc(p1.x, p1.y, p.x-p1.x, p.y-p1.y, 30, 120);
        break;
      case LINE2D:
      case POLYGON:
        if (p != null) g.drawLine(p1.x, p1.y, p.x, p.y);
        p = ev.getPoint();
        g.drawLine(p1.x, p1.y, p.x, p.y);
        break;
      case QUADCURVE2D:
        if (pointIndex == 1) {
          if (p != null) g.drawLine(p1.x, p1.y, p.x, p.y);
          p = ev.getPoint();
          g.drawLine(p1.x, p1.y, p.x, p.y);
        } else {
          Point p2 = (Point)points.get(pointIndex-2);
          if (p != null) g.draw(partialShape);
          p = ev.getPoint();
          partialShape = new QuadCurve2D.Float(p2.x, p2.y, p1.x, p1.y, p.x, p.y);
          g.draw(partialShape);
        }
        break;
      case CUBICCURVE2D:
        if (pointIndex == 1) {
          if (p != null) g.drawLine(p1.x, p1.y, p.x, p.y);
          p = ev.getPoint();
          g.drawLine(p1.x, p1.y, p.x, p.y);
        } else if (pointIndex == 2) {
          Point p2 = (Point)points.get(pointIndex-2);
          if (p != null) g.draw(partialShape);
          p = ev.getPoint();
          partialShape = new QuadCurve2D.Float(p2.x, p2.y, p1.x, p1.y, p.x, p.y);
          g.draw(partialShape);
        } else {
          Point p2 = (Point)points.get(pointIndex-2);
          Point p3 = (Point)points.get(pointIndex-3);
          if (p != null) g.draw(partialShape);
          p = ev.getPoint();
          partialShape = new CubicCurve2D.Float(p3.x, p3.y, p2.x, p2.y, p1.x, p1.y, p.x, p.y);
          g.draw(partialShape);
        }
        break;
    }
  }
 
    public void keyTyped(KeyEvent e) {
        System.out.println("test");
        throw new UnsupportedOperationException("Not supported yet.");
    }
 
    public void keyPressed(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
 
    public void keyReleased(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
}

Let's see what the problem is.

What key typed are you looking for?

You never told it what key in your keyListener.

hello,

Thanks for the reply guys,

I just want it to print something on the console as soon as I press any key....I building it from the ground up...I am planning to use either the menu or the key-shortcuts on the keyboard to select a shape to draw

Thanks again guys

First, a component must have focus for it to receive KeyEvents, which may be the problem. You can try to call requestFocus and see if that rectifies things. Second, not sure why you are using a JApplet instead of a JPanel. Last, In your situation you might look into using Key Bindings