JList not showing JScrollpane or changing size

Question

I have the following code:

    JList<Song> list = new JList<Song>(this.lib);
    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    list.setLayoutOrientation(JList.VERTICAL);
    list.setVisibleRowCount(3);
    list.setSize(1, 1);


    JScrollPane listScroller = new JScrollPane();
    listScroller.setViewportView(list);
    list.setSize(10, 10);
    setLayout(new FlowLayout(FlowLayout.LEFT,10,10));
    add(list);

I am not sure what is wrong here. When I look at the JFrame, I see the list in a single box with all 9 items that I have in my list. I tried messing with the size to see if I could get that to work but it isn't. The size doesn't seem to change no matter what I set it to.

My goal is to have a vertical and horizontal scroll-bar when necessary and a JList that is of some fixed size (fixed compared to the frame size would be best if possible).

MadProgrammer · Accepted Answer · 2014-02-11T06:34:03.540

5

You're adding the list to the container, not the listScroller.

JScrollPane listScroller = new JScrollPane();
listScroller.setViewportView(list);
list.setSize(10, 10);
setLayout(new FlowLayout(FlowLayout.LEFT,10,10));
add(list);

You should try using something like...

JScrollPane listScroller = new JScrollPane();
listScroller.setViewportView(list);
setLayout(new FlowLayout(FlowLayout.LEFT,10,10));    
//add(list); 
add(listScroller);

I think you will also find list.setSize(10, 10); is pointless, as the JScrollPane (actually the viewport, but lets keep it simple) has it's own layout manager.

You should take a look at Jlist#setVisibleRowCount if you want to affect the number of visible rows a JList will show before it needs to be scrolled.

The actual width and height of each row is determined by the ListCellRenderer, but you can use JList#setPrototypeCellValue to affect how these might be calculated.

edited Feb 11 '14 at 06:34

answered Feb 11 '14 at 02:32

MadProgrammer

343,457
22
230
366

I changed it to include "add(listScroller)" and that still didnt work. Also, I set the visible row count in the chuck of code above as 3. It is displaying everything in the list at once. – Brandon Amir Feb 11 '14 at 02:48
Until you provide a [MCVE](https://stackoverflow.com/help/mcve) anything I suggest is academic, but it sounds like you are still adding the `list` directly to the container somewhere – MadProgrammer Feb 11 '14 at 02:49
ok. thank you. I thought i was supposed to be adding BOTH. thank you! – Brandon Amir Feb 11 '14 at 02:52
Sorry, my bad, I'll update the question to reflect what I mean ;) – MadProgrammer Feb 11 '14 at 02:54
@AndrewThompson My bad, copy and pasted code in second example :P – MadProgrammer Feb 11 '14 at 06:34
Actually, Only after reviewing the edits did I note you had already explicitly mentioned it. :P – Andrew Thompson Feb 11 '14 at 06:35
@AndrewThompson Hay, more examples are always welcome ;) – MadProgrammer Feb 11 '14 at 06:48
Well in that case, I'll reinstate the part of the comment that was not nonsense. ;) OP, see the code after **Edit 1** in [this answer](http://stackoverflow.com/a/21678096/418556) for an example of using `setVisibleRowCount(..)`. – Andrew Thompson Feb 11 '14 at 06:51

JList not showing JScrollpane or changing size

1 Answers1