JTable width

Question

I've got the following code:
public class JMyFrame
extends JFrame
  public JTable jTable;
  public JScrollPane jScrollPane;
  public JMyFrame()
    setSize(APP_WIDTH, APP_HEIGHT);
    setResizable(false);
    jTable = new JTable(...);
    jScrollPane = new JScrollPane(jTable);
    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());
    contentPane.add(jScrollPane, BorderLayout.CENTER);   
  public static void main(String[] args)
    try {
      JFrame jFrame = new JMyFrame();
      jFrame.addWindowListener(
        new WindowAdapter()
          public void windowClosing(WindowEvent e)
            System.exit(0);
      jFrame.setVisible(true);
    } catch (Exception e) {
      e.printStackTrace();
}I want to adjust the size of the columns depending on the avalaible width. How can I know the real avalaible width before the table is going to be shown in the screen?
If I add the following lines of code just before the end of the JMyFrame constructor:
System.err.println("jTable.getSize()=" + jTable.getSize());
System.err.println("jTable.getPreferredSize()=" + jTable.getPreferredSize());
System.err.println("jScrollPane.getSize()=" + jScrollPane.getSize());
System.err.println("jScrollPane.getPreferredSize()=" + jScrollPane.getPreferredSize());
System.err.println("jScrollPane.getViewport().getSize()=" + jScrollPane.getViewport().getSize());
System.err.println("jScrollPane.getViewport().getPreferredSize()=" + jScrollPane.getViewport().getPreferredSize());I get:
jTable.getSize()=java.awt.Dimension[width=0,height=0]
jTable.getPreferredSize()=java.awt.Dimension[width=150,height=32]
jScrollPane.getSize()=java.awt.Dimension[width=0,height=0]
jScrollPane.getPreferredSize()=java.awt.Dimension[width=470,height=404]
jScrollPane.getViewport().getSize()=java.awt.Dimension[width=0,height=0]
jScrollPane.getViewport().getPreferredSize()=java.awt.Dimension[width=450,height=400]but neither of these values represent the real avalaible width.
I've added a button in order to get more information after everything is displayed on the screen. When I clicked the same lines of code show totally different results:
jTable.getSize()=java.awt.Dimension[width=150,height=32]
jTable.getPreferredSize()=java.awt.Dimension[width=150,height=32]
jScrollPane.getSize()=java.awt.Dimension[width=594,height=350]
jScrollPane.getPreferredSize()=java.awt.Dimension[width=470,height=424]
jScrollPane.getViewport().getSize()=java.awt.Dimension[width=574,height=326]
jScrollPane.getViewport().getPreferredSize()=java.awt.Dimension[width=450,height=400]In this case, the value returned by jScrollPane.getViewport().getSize() do represent the avalaible width and height.
I guess this happens because this way I'm getting this values after the whole applications in displayed on the screen. Is there a way to do it before?

Answer 1

I doesn't work. Everytime I execute this code:
System.err.println("jTable.getSize()=" + jTable.getSize());
System.err.println("jTable.getPreferredSize()=" + jTable.getPreferredSize());
System.err.println("jScrollPane.getSize()=" + jScrollPane.getSize());
System.err.println("jScrollPane.getPreferredSize()=" + jScrollPane.getPreferredSize());
System.err.println("jScrollPane.getViewport().getSize()=" + jScrollPane.getViewport().getSize());
System.err.println("jScrollPane.getViewport().getPreferredSize()=" + jScrollPane.getViewport().getPreferredSize());before executing jFrame.setVisible(true) I get:
jTable.getSize()=java.awt.Dimension[width=0,height=0]
jTable.getPreferredSize()=java.awt.Dimension[width=150,height=32]
jScrollPane.getSize()=java.awt.Dimension[width=0,height=0]
jScrollPane.getPreferredSize()=java.awt.Dimension[width=470,height=404]
jScrollPane.getViewport().getSize()=java.awt.Dimension[width=0,height=0]
jScrollPane.getViewport().getPreferredSize()=java.awt.Dimension[width=450,height=400]But If I execute it after executing jFrame.setVisible(true) I get:
jTable.getSize()=java.awt.Dimension[width=150,height=32]
jTable.getPreferredSize()=java.awt.Dimension[width=150,height=32]
jScrollPane.getSize()=java.awt.Dimension[width=394,height=97]
jScrollPane.getPreferredSize()=java.awt.Dimension[width=470,height=424]
jScrollPane.getViewport().getSize()=java.awt.Dimension[width=374,height=73]
jScrollPane.getViewport().getPreferredSize()=java.awt.Dimension[width=450,height=400]and these values are the ones I'm looking for...but just before setting the visibility of the main frame to true.
I've also tried to do the following:
jFrame.doLayout();
System.err.println("jTable.getSize()=" + jTable.getSize());
System.err.println("jTable.getPreferredSize()=" + jTable.getPreferredSize());
System.err.println("jScrollPane.getSize()=" + jScrollPane.getSize());
System.err.println("jScrollPane.getPreferredSize()=" + jScrollPane.getPreferredSize());
System.err.println("jScrollPane.getViewport().getSize()=" + jScrollPane.getViewport().getSize());
System.err.println("jScrollPane.getViewport().getPreferredSize()=" + jScrollPane.getViewport().getPreferredSize());
jFrame.setVisible(true)or
jFrame.validate();
System.err.println("jTable.getSize()=" + jTable.getSize());
System.err.println("jTable.getPreferredSize()=" + jTable.getPreferredSize());
System.err.println("jScrollPane.getSize()=" + jScrollPane.getSize());
System.err.println("jScrollPane.getPreferredSize()=" + jScrollPane.getPreferredSize());
System.err.println("jScrollPane.getViewport().getSize()=" + jScrollPane.getViewport().getSize());
System.err.println("jScrollPane.getViewport().getPreferredSize()=" + jScrollPane.getViewport().getPreferredSize());
jFrame.setVisible(true)but it doesn't work either.