BackgroundPanel.java cannot be placed in BorderLayout.NORTH

[chop ficaro]

i am trying to put a picture on the top of my swing GUI that stretches horizontally to fit the width of the window as it resizes

http://www.camick.com/java/source/BackgroundPanel.java
this is the code for a commonly used function that scales images to their components size. it works by overloading the paintcontainer class, which is called every time the window resizes, which then calls the paint class. they simply grab the size of the container and draw the image to those dimensions

the image that needs to be resized must be placed in BorderLayout.NORTH, because the rest of my GUI is in BorderLayout.CENTER, but BackgroundPanel cant be placed in NORTH, the image disappears, even with a minimum size set. it cant be placed inside a panel inside a panel inside NORTH either. ive been reading over the code for BackgroundPanel and its driving me crazy i cant figure out why

here is some short example code, not my program but it simplifies the problem:

import java.awt.*;
import javax.swing.*;
import java.awt.event.WindowEvent;

public class JPanel1 extends JFrame 
{
	public static void main(String[] args) 
	{
		new JPanel1();
	}

	public JPanel1() 
	{
		enableEvents(AWTEvent.WINDOW_EVENT_MASK);
		add(mainJPanel());
		pack();
		setVisible(true);
	}

	
	//debug space center to streatch
	private JPanel mainJPanel()
	{
		JPanel JPanel = new JPanel();
		BorderLayout layout = new BorderLayout();
		this.setMinimumSize( new Dimension( 224, 224 ) );
		JPanel.setLayout(layout);
		JPanel.add(mainJPanel2(),BorderLayout.NORTH);
		return(JPanel);
	}

	
	//debug space center to streatch
	private JPanel mainJPanel2()
	{
		JPanel JPanel = new JPanel();
		BorderLayout layout = new BorderLayout();
		JPanel.setLayout(layout);
		JPanel.add(JPanel2(),BorderLayout.CENTER);
		return(JPanel);
	}
	
	
	private JPanel JPanel2() 
	{
		BorderLayout layout = new BorderLayout();
		this.setLayout(layout);
		Toolkit toolkit = Toolkit.getDefaultToolkit(); 
		Image duke = toolkit.getImage("sun.jpg");
		BackgroundPanel panel = new BackgroundPanel(duke, BackgroundPanel.SCALED);
		//panel.setMinimumSize( new Dimension( 224, 224 ) );
		this.setMinimumSize( new Dimension( 224, 224 ) );
		GradientPaint paint = new GradientPaint(0, 0, Color.BLUE, 600, 0, Color.RED);
		panel.setPaint(paint);
		return panel;
	}
	
	//exit when closed
    public void processWindowEvent(WindowEvent event)
	{
		if(event.getID() == WindowEvent.WINDOW_CLOSING)
		System.exit(0);
    }

}

[Darryl Burke]

chop ficaro wrote:

public class JPanel1 extends JFrame 

Puh-lease!

[Rob Spoor]

chop ficaro wrote:

JPanel JPanel = new JPanel();

I really suggest you name your variables differently. Never use a class name as variable name. It makes your code confusing to read; when I first glanced over your code I thought I saw a few static calls:

JPanel.setLayout(layout);
JPanel.add(mainJPanel2(),BorderLayout.NORTH);

Anyway, I see one problem with your BackgroundPanel. It has no children, so its size will be 0x0. Try giving it a preferred size.

[Darryl Burke]

Cross posted
http://www.javaprogrammingforums.com/java-theory-questions/5107-backgroundpanel-java-cannot-placed-borderlayout-north.html

edit
http://www.java-forums.org/new-java/31999-backgroundpanel-java-cannot-placed-borderlayout-north.html
http://forums.devshed.com/java-help-9/backgroundpanel-java-cannot-be-placed-in-borderlayout-north-739999.html
http://www.javakb.com/Uwe/Forum.aspx/java-programmer/49800/BackgroundPanel-java-cannot-be-placed-in-BorderLayout
http://java.net/story/backgroundpaneljava-cannot-be-placed-borderlayoutnorth

[Rob Spoor]

Chop, you've been informed by both Darryl and me back in May that you should BeForthrightWhenCrossPostingToOtherSites.

[chop ficaro]

Rob Prime wrote:

chop ficaro wrote:

JPanel JPanel = new JPanel();

I really suggest you name your variables differently. Never use a class name as variable name. It makes your code confusing to read; when I first glanced over your code I thought I saw a few static calls:

JPanel.setLayout(layout);
JPanel.add(mainJPanel2(),BorderLayout.NORTH);

Anyway, I see one problem with your BackgroundPanel. It has no children, so its size will be 0x0. Try giving it a preferred size.

thats what this is
//panel.setMinimumSize( new Dimension( 224, 224 ) );
it doesnt work remove the comment mark and see

[Rob Camick]

Why don't you actually try doing what the suggestion was? We don't have time to keep repeating the same suggestion over and over (especially when you don't bother to reply to other postings when you get help).

[Rob Spoor]

The minimum size is not the preferred size.

[chop ficaro]

tyvm! your suggestion fixed my problem!

[Campbell Ritchie]

chop ficaro wrote:tyvm

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