How to make a "static background" on the scrollpane ?

[Lando Chan]

Hello, I have a problem when the scrollpane are too long. Just look at the image

How to make the image stay the same while I scroll down the panel ?

This is part of my code

GridLayout grid = new GridLayout(0, 3, 50, 10);
		homebackground homepanel = new homebackground();
		JPanel gridpanel = new JPanel(grid);
		gridpanel.setOpaque(false);
		gridpanel.add(question);
		gridpanel.add(answer);
		gridpanel.add(delete);
		homepanel.add(phome);

scroller = new  JScrollPane(homepanel);
		scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
		scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
		f.getContentPane().add(BorderLayout.CENTER, scroller);

And this is how I set the background image

class homebackground extends JPanel {
		public void paintComponent (Graphics g){
			BufferedImage image = null;
			File f = null;
			try{
				f = new File ("play.jpg");
				image = new BufferedImage(1350, 740, BufferedImage.TYPE_INT_ARGB);
				image = ImageIO.read(f);
			} catch (IOException ex){System.out.print("caught"); ex.printStackTrace();}
			g.drawImage(image,0,0,1350,740,null);
		}
	}

I also have tried on my own, two trial.
First, I search wheter I can set the background on the frame instead, and the result is none. It is not possible

Second I tried to make a new panel, and put this as my background panel, and add the scrollpane to this panel (before, I put the scrollpane on the frame). But, the problem comes from the unmoving scrollpane/ Failed
I tried another alternative as to set the layout of this panel as border layout, the scrollpane is working fine, but the background cannot be seen even though I setOpaque(false) this panel.

Please help me. Thank You.

[Campbell Ritchie]

How are you adding that image to the scroll pane? How are you adding that scroll pane to the frame? Where do all the Japanese→English translations come from?

[Lando Chan]

It is a long code and I do not think that other part of code will affect the solution in any way. In short I use combination of ArrayList<TextArea> for those japanese english translation and ArrayList<JButton> for those delete button. and adding all of them in sequence to the gridpanel.

[Lando Chan]

Adding the image ? Do not you see ? I use paintComponent to draw that image.

[Lando Chan]

It is may be unclear but f is a frame.
This is the code which I have included in the previous post

 f.getContentPane().add(BorderLayout.CENTER, scroller);

[Rob Camick]

You need to paint the image on the viewport of the scroll pane and make your panel transparent:

JPanel panel = new JPanel();
panel.setOpaque( false );
// add components to the panel
        
JViewport viewport = new JViewport()
{
	@Override
	protected void paintComponent(Graphics g)
	{
		super.paintComponent(g);

		g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
	}
};

JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewport( viewport );
scrollPane.setViewportView( panel );

[Lando Chan]

Thank You, It worked.