I have an applet that works in Internet Explorer (IE) but the getsize() method seems to throw Netscape4 (NS4). WHAT DOES THE APPLET DO? The applet loads a image as background and reads each line of a text file (results.txt) for both text to scroll across applet and set each line of text with the relevant hyperlink (the code uses the | character as a delimiter between the text and it's related hyperlink. ********************************************************* NETSCAPE JAVA CONSOLE: Thread started # Applet exception: exception: java.lang.NullPointerException java.lang.NullPointerException Thread stopped 13 # Applet exception: error: java.lang.NoSuchMethodError: java.awt.Component: method getSize ()Ljava/awt/Dimension; not found java.lang.NoSuchMethodError: java.awt.Component: method getSize ()Ljava/awt/Dimension; not found ********************************************************* APPLET SCROLLER SOURCE: //reads a file and scrolls contents across screen with picture background //written by peter guillebaud import java.applet.*; import java.awt.*; import java.awt.event.*; import java.util.*; import java.io.*; import java.net.*; public class Ticker extends Applet implements Runnable { private Font ft = new Font("Verdana",Font.BOLD,11); private String text = "INSL" ; private Thread myThread; private Image imageBuffer = null;//double buff to stop flicker private Image pic; int speed = 200; int xPos = 100; private String filename = "results.txt";// file to read with alert info Vector vecText = new Vector(); Vector vecUrls = new Vector(); int vecSize = 0; int counter; int curPos; FontMetrics fm; boolean mOver = false; //mouseover
public void init() { String param; param = getParameter ( "bgImage" ); System.out.println ( "The parameter is " + param ); pic = getImage ( getDocumentBase(), param ); fm = getFontMetrics(ft); readFile(); counter = 0; } public boolean mouseEnter(Event e, int x, int y) { stop(); mOver = true; curPos = e.y; System.out.println ( curPos ); repaint(); return true; } public boolean mouseExit(Event e, int x, int y) { start(); mOver = false; repaint(); return true; } public boolean mouseDown ( Event e, int x, int y ) { //try //{ System.out.println ( vecUrls.elementAt ( counter )); URL url = (URL)vecUrls.elementAt ( counter ); getAppletContext().showDocument ( url ); //} //catch ( MalformedURLException mue) //{ // System.out.println ( mue.toString()); //} return true; } //called at init, populates vectors by reading file public void readFile( ) { try { URL fileUrl = new URL ( getDocumentBase(), filename ); try { BufferedReader br = new BufferedReader (new InputStreamReader ( fileUrl.openStream() ) ); String line = br.readLine(); while ( line != null ) { StringTokenizer tokens = new StringTokenizer ( line, "|"); vecText.addElement ( tokens.nextElement()); while ( tokens.hasMoreElements()) { vecUrls.addElement ( new URL( getDocumentBase(), tokens.nextToken())); } //text += line; line = br.readLine(); } //System.out.println ( text ); br.close(); } catch ( FileNotFoundException fnfe ) { System.out.println ( fnfe.toString()); } catch ( IOException ioe ) { System.out.println ( ioe.toString()); } } catch ( MalformedURLException mue ) { System.out.println ( mue.toString()); } //set the size of the vector vecSize = vecText.size(); }
public void render ( Graphics g ) { g = imageBuffer.getGraphics(); // g.setColor ( Color.black ); g.setColor ( new Color(Integer.parseInt ( "CCFFFF", 16 ))); g.fillRect(0, 0, 632, 15); // g.fillRect(0, 0, getSize().width, getSize().height); g.drawImage ( pic,0,0,632, 15, this ); // g.setColor ( Color.black ); g.setFont ( ft );
if ( mOver ) g.setColor ( Color.white ); //get the text line out of the vector String lineToDisplay = (String)vecText.elementAt ( counter ); //find the length of this string int length = fm.stringWidth ( lineToDisplay ); //if the string length is out of sight get the next string and reset the positioning if ( length + xPos < 100 && counter < vecText.size() -1) { counter ++; xPos = 632; } //if we've reached the end of the alerts go back to the beginning if ( counter == vecText.size() -1) counter = 0;
g.drawString ( lineToDisplay, xPos, 11 ); } //called by repaint in the thread runner public void update ( Graphics g ) { //draws scrolling text offscreen render( g); //calls paint which draws offscreen stuff onscreen paint ( g ); }
public void paint(Graphics g) { if (imageBuffer == null) { // double buffering imageBuffer = createImage(632, 15); // imageBuffer = createImage(getSize().width, getSize().height); } g.drawImage(imageBuffer, 0, 0, null); } public void start() { myThread = new Thread(this); myThread.start(); System.out.println ( "Thread started" ); } public void stop() { //myThread = null; myThread.stop(); System.out.println ( "Thread stopped" ); } public void run() { try { while(true) { repaint(); myThread.sleep(speed); xPos--; } } catch (InterruptedException e){} } } ********************************************************* RESULT.TXT : 2001-11-06 text 1|http://www.netscape.com/ 2001-11-06 text 2|http://www.microsoft.com/ 2001-11-06 text 3|http://java.sun.com/ 2001-11-06 text 4|http://applets.java.sun.com/ 2001-11-06 text 5|http://www.sun.com/ 2001-11-06 text 6|http://www.apache.org/ 2001-11-06 text 7|http://jakarta.apache.org/ _________________________________________________ Any thoughts would be much appreciated.
Manfred Leonhardt
Ranch Hand
Joined: Jan 09, 2001
Posts: 1492
posted
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Hi Nicolas, getSize() method for components only came into being with Java 1.1. I am not really sure, but if you use older than Netscape 4.5 it doesn't support 1.1 (only 1.0.x). Regards, Manfred.
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NETSCAPE JAVA CONSOLE:
