0

I'm trying to create a JScrollPane that contains a gallery of Images and JFreeCharts. For now I'm just using colored rectangles to test.

I've got two problems, first of which is that I don't quite understand my own code (it somewhat does what I need it to but I'm not sure why).

My main confusion here is, and please see the code below, the need for a panel that holds my image-holding panels: 

panel.add(panelHolder[m][n]);

I would think that I could just add the panels directly to the scrollPanel instead 

scrollPanel.add(panelHolder[m][n])

But when I do so the scrollPanel will appear empty.

My second problem can be seen in the following screenshot: There are massive gaps between the images, and the sizes of these seem to change when I play with the rectangle size? I've tried giving panel a GridLayout to avoid margins but this doesn't change anything.

enter image description here

    //Load Images
    Image img = ImageIO.read(new File("H:\\testimg.PNG"));
    BufferedImage bimg = toBufferedImage(img);      
    ImageIcon icon1 = new ImageIcon(bimg);
    JLabel iconholder = new JLabel(icon1);

    Image img1 = ImageIO.read(new File("H:\\testimg2.PNG"));
    BufferedImage bimg1 = toBufferedImage(img1);        
    ImageIcon icon2 = new ImageIcon(bimg1);
    JLabel iconholder1 = new JLabel(icon2);

    Image img2 = ImageIO.read(new File("H:\\testimg3.PNG"));
    BufferedImage bimg2 = toBufferedImage(img2);        
    ImageIcon icon3 = new ImageIcon(bimg2);
    JLabel iconholder2 = new JLabel(icon3);

    //Create Tab        
    int i=4;
    int j=2;
    JPanel[][] panelHolder = new JPanel[i][j];
    GridLayout glay = new GridLayout(i,j);
    glay.setVgap(0);
    glay.setHgap(0);

    JPanel panel = new JPanel(glay);
    JScrollPane scrollPanel = new JScrollPane(panel);

    //Put image holding panels in scrollPanel
    for(int m = 0; m < i; m++) {
       for(int n = 0; n < j; n++) {
          panelHolder[m][n] = new JPanel();
          panel.add(panelHolder[m][n]);
       }
    }


    scrollPanel.setPreferredSize(new Dimension(410, 50));
    scrollPanel.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
    scrollPanel .setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    scrollPanel.getVerticalScrollBar().setUnitIncrement(16);  

    //Put Images in
    panelHolder[0][0].add(iconholder);
    panelHolder[3][0].add(iconholder1);
    panelHolder[1][1].add(iconholder2);
Andrew Thompson
  • 168,117
  • 40
  • 217
  • 433
Zyzyx
  • 492
  • 4
  • 18
  • 1
    Can you post an example of your desired GUI? Without it we cannot guide you, as we don't know what layout-manager could suit it better. And a proper [mre] that we can copy-paste? Your code currently lacks a `main` method, imports and more. The simpler and shorter, the better but still complete to reproduce your issue. – Frakcool Jan 22 '20 at 18:13
  • 1
    No need to create panels. Just add the JLabel directly to the panel using the GridLayout. Note when you use a GridLayout all the components are sized to the size of the largest component added to the grid. Also the grid can be resized to fill the entire space of the tabbed pane which may be giving extra space. So to prevent this from happening you may need to wrap the panel using the GridLayout in a JPanel using the FlowLayout, which respect the preferred size of the grid panel. – camickr Jan 22 '20 at 18:48
  • When posting the MRE suggested by @Frakcool, some tips: 1) One way to get image(s) for an example is to hot link to images seen in [this Q&A](http://stackoverflow.com/q/19209650/418556). E.G. [This answer](https://stackoverflow.com/a/10862262/418556) hot links to an image embedded in [this question](https://stackoverflow.com/q/10861852/418556). 2) Provide ASCII art or a simple drawing of the *intended* layout of the GUI at minimum size, and if resizable, with more width and height - to show how the extra space should be used. – Andrew Thompson Jan 23 '20 at 00:00

0 Answers0