Thread: Unable to add JPanel to JScrollPane

Hi,

I want to add a JPanel (called panel) to the mother object, in this case another JPanel. On 'panel' there should be a list of some CheckBoxes, and since their number is not constant, I want to have a possibility to scroll down the 'panel' to see them all if there are more of them. So, I wanted to add 'panel' to a JScrollPane scrollPane, but it does not work. Do you know what have I done wrong?

        JPanel panel;
        JScrollPane scrollPane;
 
//this is in the constructor of the mother object, JPanel
        panel = new JPanel();
        panel.setBorder(BorderFactory.createEtchedBorder());
        panel.setBounds(0,0,415,420);
        panel.setBackground(new Color(255,255,255));
 
        scrollPane = new JScrollPane(panel);
        add(scrollPane, 0, 40, 415, 400);
 
//method add defined in the mother object
    public void add(Component c, int x, int y, int sX, int sY)
    {
        add(c);
        c.setBounds(x,y,sX,sY);
    }

In the final program, the scrollPane appears on the mother JPanel, but without any sign of the 'panel'. I tried to add some other object to 'panel' (test JLabels and JButtons), but it was still the same - no 'panel' clipped to the scrollPane.

Thank you very much for your response.

Try this. I did not actually test this but I think this is your problem. Add the panel to the viewport of the scroll pane.

 
        JPanel panel;
        JScrollPane scrollPane;
 
//this is in the constructor of the mother object, JPanel
        panel = new JPanel();
        panel.setBorder(BorderFactory.createEtchedBorder());
        panel.setBounds(0,0,415,420);
        panel.setBackground(new Color(255,255,255));
 
        scrollPane = new JScrollPane();
        scrollPane.getViewport().add(panel)//<---Add the panel to the viewport of the scroll pane.
        add(scrollPane, 0, 40, 415, 400);
 
//method add defined in the mother object
    public void add(Component c, int x, int y, int sX, int sY)
    {
        add(c);
        c.setBounds(x,y,sX,sY);
    }

No, it has to be something else, that does very much the same. :/

I've also tried not to set bounds of 'panel' but set its preferred size, but with no success.

This I've tried before (as I mentioned above), but still nothing. I do not know what else should I do. It seems like the 'panel' was not created or what (for example, for JTextPane it does exactly the same thing, until I set its Text... but I do not know about the alternative for setText in JPanel, so I cannot try it)

I tested your code and changed setbounds to setPreferredsize and it worked. I changed your color to black to make it easier to see over the white on white.

package testing;
 
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
 
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
 
public class TestScroller extends JPanel
{
    JPanel panel;
    JScrollPane scrollPane;
 
    public TestScroller() {
		// TODO Auto-generated constructor stub
 
//this is in the constructor of the mother object, JPanel
    panel = new JPanel();
    panel.setBorder(BorderFactory.createEtchedBorder());
    //panel.setBounds(0,0,415,420);
 
    panel.setPreferredSize(new Dimension(415,420));
    panel.setBackground(Color.BLACK);
 
    scrollPane = new JScrollPane(panel);
    scrollPane.setPreferredSize(new Dimension(415,400));
    add(scrollPane);
  //  add(scrollPane, 0, 40, 415, 400);
    }
/*  //method add defined in the mother object
      public void add(Component c, int x, int y, int sX, int sY)
      {
          add(c);
          c.setBounds(x,y,sX,sY);
      }*/
 
 
 
 
	public static void main( String args[] )
	{
		JPanel baseView = new TestScroller();
		baseView.setPreferredSize(new Dimension(500,500));
		baseView.setOpaque(false);
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.getContentPane().add(baseView);
		frame.setSize(500,500);
 
		frame.setVisible(true);
		frame.repaint();
	}
}

So if preferredSize is not working for you then some where else in the code it is broken and not in the section you provide.

You're my boy mesatrin1!

Thank you guys! Yes, I am using null layout, and I know it has many disadvantages, but in this programme I wanted to have it like this. And I found the problem - the single repaint on the mother JFrame was not enough, bud when I resized it, the JPanel appeared in the JScrollPane. So, I found the solution, although it is weird, and my problem is solved. Once again, thank you for your help.