SpringLayout?

Question

Hi
I have just started lerning Java in my school, but they are only doing Applets and whith no LayoutManagers. But I want to learn more. My teacher isn't very good at this so I'm asking you. If you can tell me what is wrong with this code.
The program dosen't do anything yet so thats not the problem. I'm having problem with the SpringLayout.
Here is the code.
import javax.swing.*;
import java.awt.*;
import java.awt.Container;
import java.awt.event.*;
public class SpringDemo1 implements ActionListener{
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     Container contentPane;
    public void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("Sl�ttar T�lur");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          contentPane = frame.getContentPane();
          prentaVidmot();
          //takki.addActionListener(this);
        //S�na gluggan
        frame.pack();
        frame.setVisible(true);
     public static void prentaVidmot(){
           //Set up the content pane.
          //SpringLayout layout = new SpringLayout();
          JPanel kassi = new JPanel();
          SpringLayout layout = new SpringLayout();
          kassi.setLayout(layout);
          kassi.setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
          //Create and add the components.
          JLabel label = new JLabel("Tala: ");
          JTextField tala = new JTextField(15);
          JLabel labelNidurstodur = new JLabel("Ni�urst��ur: ");
          TextArea textabox = new TextArea(5,21);
          JButton takki = new JButton("Reikna");
          kassi.add(label);
          kassi.add(tala);
          kassi.add(labelNidurstodur);
          kassi.add(textabox);
          kassi.add(takki);
          //Stilla sta�setningu label
          kassi.putConstraint(SpringLayout.WEST, label, 5,SpringLayout.WEST, kassi);
          kassi.putConstraint(SpringLayout.NORTH, label,5,SpringLayout.NORTH, kassi);
          //Stilla sta�setningu tala
          kassi.putConstraint(SpringLayout.WEST, tala,50,SpringLayout.EAST, label);
          kassi.putConstraint(SpringLayout.NORTH, tala,5,SpringLayout.NORTH, kassi);
          //Stilla sta�setningu labelNidurstodur
          kassi.putConstraint(SpringLayout.WEST, labelNidurstodur, 0, SpringLayout.WEST, label);
          kassi.putConstraint(SpringLayout.NORTH, labelNidurstodur, 10, SpringLayout.SOUTH, label);
          //Stilla sta�setningu textabox
          kassi.putConstraint(SpringLayout.WEST, textabox, 0, SpringLayout.WEST, tala);
          kassi.putConstraint(SpringLayout.NORTH, textabox, 5, SpringLayout.SOUTH, tala);
          //Stilla sta�setningu takka
          kassi.putConstraint(SpringLayout.EAST, takki,0,SpringLayout.EAST, textabox);
          kassi.putConstraint(SpringLayout.NORTH, takki,10,SpringLayout.SOUTH, textabox);
          //Stilla st�r� glugga
     public void actionPerformed(ActionEvent event){
          double teljari = (Double.parseDouble(tala.getText()));
          System.out.println("Foo");
    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}And here is the error:
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:66: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JLabel,int,java.lang.String,javax.swing.JPanel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.WEST, label, 5,SpringLayout.WEST, kassi);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:67: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JLabel,int,java.lang.String,javax.swing.JPanel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.NORTH, label,5,SpringLayout.NORTH, kassi);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:70: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JTextField,int,java.lang.String,javax.swing.JLabel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.WEST, tala,50,SpringLayout.EAST, label);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:71: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JTextField,int,java.lang.String,javax.swing.JPanel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.NORTH, tala,5,SpringLayout.NORTH, kassi);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:74: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JLabel,int,java.lang.String,javax.swing.JLabel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.WEST, labelNidurstodur, 0, SpringLayout.WEST, label);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:75: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JLabel,int,java.lang.String,javax.swing.JLabel)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.NORTH, labelNidurstodur, 10, SpringLayout.SOUTH, label);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:78: cannot resolve symbol
symbol : method putConstraint (java.lang.String,java.awt.TextArea,int,java.lang.String,javax.swing.JTextField)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.WEST, textabox, 0, SpringLayout.WEST, tala);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:79: cannot resolve symbol
symbol : method putConstraint (java.lang.String,java.awt.TextArea,int,java.lang.String,javax.swing.JTextField)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.NORTH, textabox, 5, SpringLayout.SOUTH, tala);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:82: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JButton,int,java.lang.String,java.awt.TextArea)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.EAST, takki,0,SpringLayout.EAST, textabox);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:83: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JButton,int,java.lang.String,java.awt.TextArea)
location: class javax.swing.JPanel
          kassi.putConstraint(SpringLayout.NORTH, takki,10,SpringLayout.SOUTH, textabox);
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:90: cannot resolve symbol
symbol : variable tala
location: class SpringDemo1
          double teljari = (Double.parseDouble(tala.getText()));
^
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:101: non-static method createAndShowGUI() cannot be referenced from a static context
createAndShowGUI();
^
12 errors
Tool completed with exit code 1

Answer 1

If you are just learning Java, you should not start with GUI programming. You'll need all the basics to really understand what you are doing.
For example you seem to have problems reading and understanding error messages. That's understandable, because at first they may seem intimidating.
Let's look at the first error:
N:\T�l103\Forritun\javasafn\forrit_04_01\SpringDemo1.java:66: cannot resolve symbol
symbol : method putConstraint (java.lang.String,javax.swing.JLabel,int,java.lang.String,javax.swing.JPanel)
location: class javax.swing.JPanel
kassi.putConstraint(SpringLayout.WEST, label, 5,SpringLayout.WEST, kassi);
^The first line tells you where the problem occurs (the file and the line nummer) and what the general error is ("cannot resolve symbol" means that some class/method/variable/... can't be found).
The second line tells you which symbol it can't find (a method named putConstraint taking the list of parameters specified).
The third line tells you where it tried to find the symbol (the class JPanel).
The fourth line shows you the line of code that didn't compile.
You should now analyze and fix each error one, one after the other.