Animazioni

Stampa data e ora

/*
  Stampa la data corrente
*/

import java.awt.*;
import java.util.*;
import java.text.*;

public class DataOra extends java.applet.Applet implements Runnable {
  Thread runner;

  public void start() {
    if( runner==null ) {
      runner=new Thread(this);
      runner.start();
    }
  }

  public void stop() {
    if( runner!=null ) {
      runner.stop();
      runner=null;
    }
  }

  public void run() {
    while(true) {
      repaint();
      try {
        Thread.sleep(200);
      }
      catch( InterruptedException e ) { }
    }
  }

  public void update(Graphics g) {
    Date now=new Date();
    SimpleDateFormat dateformat =
         new SimpleDateFormat ("dd MMMM yyyy - HH:mm.ss");
    Font f = new Font("TimesRoman", Font.PLAIN, 14);

    g.setFont(f);

    g.clearRect(10,0,500,40);
    g.drawString(dateformat.format(now),10,20);

  }

  public void paint(Graphics g) {
    update(g);
  }
}

Scrittura carattere per carattere

/*
  Scrive una stringa carattere per carattere
*/

import java.awt.*;

public class SlowWrite extends java.applet.Applet implements Runnable {
  Thread runner;
  Font f;
  String towrite="Questa stringa viene scritta lentamente";
  int writeto=0;

  public void start() {
    if( runner==null ) {
      runner=new Thread(this);
      runner.start();
    }
  }

  public void stop() {
    if( runner!=null ) {
      runner.stop();
      runner=null;
    }
  }

  public void run() {
    int i;

    for(writeto=0;; writeto=writeto+1) {
      writeto=writeto%towrite.length();
      repaint();
      if( towrite.charAt(writeto)!=' ' ) {
        try {
          Thread.sleep(200);
        }
        catch( InterruptedException e ) { }
      }
    }
  }

  public void paint(Graphics g) {
    f=new Font("Courier", Font.PLAIN, 18);
    int i;

    g.setFont(f);

    for(i=0; i<=writeto; i++)
      g.drawString(towrite.substring(i,i+1) , i*10, 20 );
  }

}

Figure geometriche in movimento

import java.awt.*;

public class Ball extends java.applet.Applet implements Runnable {
  Thread runner;
  int x,y;

  public void start() {
    if( runner==null ) {
      runner=new Thread(this);
      runner.start();
    }
  }

  public void stop() {
    if( runner!=null ) {
      runner.stop();
      runner=null;
    }
  }

  public void run() {
    int i=0;

    for(x=0; x<=255; x++) {
      y=x;

      repaint();
      try { Thread.sleep(100); }
      catch( InterruptedException e ) { }
    }
  }

  public void paint(Graphics g) {
    g.fillOval(x,y,20,20);
  }
}