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).

Answer 1

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.