Programming: Java - Добро пожаловать в мир Java

Исходный текст аплета Options представлен в листинге 1.

Листинг 1. Файл Options.java

import java.applet.*;
import java.awt.*;

public class Options extends Applet
{
  FirstPanel pPanel1;
  CardPanel pCard;
  ControlPanel pControl;

  public String getAppletInfo()
  {
    return "Name: Options";
  }

  public void init()
  {
    setLayout(new GridLayout(3, 1));

    pPanel1 = new FirstPanel();
    add(pPanel1);

    pCard = new CardPanel(pPanel1);
    add(pCard);

    pControl = new ControlPanel(pCard);
    add(pControl);

    pPanel1.setBackground(Color.yellow);
    pPanel1.setForeground(Color.black);

    repaint();
  }
}

class FirstPanel extends Panel
{
  String szFontName = "TimesRoman";

  public void paint(Graphics g)
  {
    Dimension dimAppWndDimension = getSize();

    g.drawRect(0, 0, 
      dimAppWndDimension.width  - 1, 
      dimAppWndDimension.height - 1);

    g.setFont(new Font(szFontName,
      Font.PLAIN, 24));
    g.drawString("First panel", 10, 50);

    super.paint(g);
  }
}

class CardPanel extends Panel
{
  Panel pBgColor;
  Panel pFgColor;
  Panel pFont;

  Panel pControlled;

  Choice chBgColor;
  Choice chFgColor;
  Choice chFont;

  Label lbBgColor;
  Label lbFgColor;
  Label lbFont;

  public CardPanel(Panel pControlledPanel)
  {
    pControlled = pControlledPanel;

    setLayout(new CardLayout(5, 5));

    pBgColor = new Panel();
    pFgColor = new Panel();
    pFont    = new Panel();

    add("BgColor", pBgColor);
    add("FgColor", pFgColor);
    add("Font", pFont);

    chBgColor = new Choice();
    chFgColor = new Choice();
    chFont    = new Choice();

    chBgColor.add("Yellow");
    chBgColor.add("Green");
    chBgColor.add("White");

    chFgColor.add("Black");
    chFgColor.add("Red");
    chFgColor.add("Green");

    chFont.add("TimesRoman");
    chFont.add("Helvetica");
    chFont.add("Courier");

    lbBgColor = new Label("Background color");
    lbFgColor = new Label("Foreground color");
    lbFont = new Label("Font");

    pBgColor.add(lbBgColor);
    pBgColor.add(chBgColor);

    pFgColor.add(lbFgColor);
    pFgColor.add(chFgColor);

    pFont.add(lbFont);
    pFont.add(chFont);
  }  

  public void paint(Graphics g)
  {
    Dimension dimAppWndDimension = getSize();
    g.drawRect(0, 0, 
      dimAppWndDimension.width  - 1, 
      dimAppWndDimension.height - 1);

    super.paint(g);
  }

  public boolean action(Event evt, Object obj)
  {
    Choice ch; 

    if(evt.target instanceof Choice)
    {
      ch = (Choice)evt.target;

      if(evt.target.equals(chBgColor))
      {
	if(ch.getSelectedIndex() == 0)
	  pControlled.setBackground(
            Color.yellow);

	else if(ch.getSelectedIndex() == 1)
	  pControlled.setBackground(
            Color.green);

	else if(ch.getSelectedIndex() == 2)
	  pControlled.setBackground(
            Color.white);
      }
      else if(evt.target.equals(chFgColor))
      {
	if(ch.getSelectedIndex() == 0)
	  pControlled.setForeground(
            Color.black);

	else if(ch.getSelectedIndex() == 1)
	  pControlled.setForeground(
            Color.red);

	else if(ch.getSelectedIndex() == 2)
	  pControlled.setForeground(
            Color.green);
      }
      else if(evt.target.equals(chFont))
      {
	if(ch.getSelectedIndex() == 0)
	  ((FirstPanel)pControlled).szFontName
            = "TimesRoman";

	else if(ch.getSelectedIndex() == 1)
	  ((FirstPanel)pControlled).szFontName
            = "Helvetica";

	else if(ch.getSelectedIndex() == 2)
	  ((FirstPanel)pControlled).szFontName
            = "Courier";
      }
      else
      {
	return false;
      }
      pControlled.repaint();

      return true;
    }
    return false;
  }
}

class ControlPanel extends Panel
{
  Button btNext;
  Button btPrev;
  Button btBgColor;
  Button btFgColor;
  Button btFont;
  Panel pCard;

  public ControlPanel(Panel pCardPanel)
  {
    pCard = pCardPanel;
    setLayout(new GridLayout(2,3));

    btBgColor = new Button("Background Color");
    btFgColor = new Button("Foreground Color");
    btFont = new Button("Set Font");
    btNext = new Button("Next");
    btPrev = new Button("Prev");

    add(btBgColor);
    add(btFgColor);
    add(btFont);
    add(btNext);
    add(btPrev);
  }

  public boolean action(Event evt, Object obj)
  {
    if(evt.target instanceof Button)
    {
      if(evt.target.equals(btBgColor))
      {
	((CardLayout)pCard.getLayout()).show(
            pCard, "BgColor");
      }
      else if(evt.target.equals(btFgColor))
      {
	((CardLayout)pCard.getLayout()).show(
            pCard, "FgColor");
      }
      else if(evt.target.equals(btFont))
      {
	((CardLayout)pCard.getLayout()).show(
            pCard, "Font");
      }
      else if(evt.target.equals(btNext))
      {
	((CardLayout)pCard.getLayout()).next(
            pCard);
      }
      else if(evt.target.equals(btPrev))
      {
	((CardLayout)pCard.getLayout()).
            previous(pCard);
      }
      else
      {
	return false;
      }
      return true;
    }
    return false;
  }
}

Исходный текст документа HTML, созданный для аплета Options системой Java WorkShop, представлен в листинге 2.

Листинг 2. Файл Options.tmp.html

<applet name="Options"
  code="Options" 
  codebase=
"file:/E:/Sun/Articles/vol8/src/Options"
  width="500"
  height="600"
  align="Top"
  alt="If you had a java-enabled browser,
 you would see an applet here.">
 <hr>If your browser recognized the applet tag,
you would see an applet here.<hr>
</applet>