JScroll not working with JList

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kodonne2 - 08 Jan 2004 19:25 GMT

this is someone elses post - but I'm having the same problem with my GUI and can't figure it out. No body responded to his post so I'll try again, please help!:

I've put a JList in a JScrollPane:

addLinks1List = new JList();
addLinks1Pane = new JScrollPane();

addLinks1Pane.setViewportView(addLinks1List);

The ScrollPane is in a GridBagLayout

The list is filled and orientation is VERTICAL. When my JList gets
bigger than the viewport, no ScrollBar appears, even when I state that a
vertical scrollbar should appear, it is never scrollable.
The data is in the list, I am sure of that.

Does anyone know why my List never becomes Scrollable?

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ak - 08 Jan 2004 19:26 GMT

short example?

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kodonne2 - 08 Jan 2004 20:52 GMT

There is a short example below - I added all of my properties too for each - just in case something I'm doing in JList is nullifing what I'm doing in JScrollPane or vice versa? Thanks in advance for any help!

JList jList1;
JScrollPane scrollPane = new JScrollPane(jList1);
listItems.add(..)

jList1 = new JList(listItems);

scrollPane.setBounds(38,117,120,114);
scrollPane.setAutoscrolls(true);
scrollPane.createVerticalScrollBar();
scrollPane.setWheelScrollingEnabled(true);
scrollPane.setNextFocusableComponent(jList1);
scrollPane.setEnabled(true);
jList1.setEnabled(true);
jList1.setAutoscrolls(true);
jList1.setDebugGraphicsOptions(0);
jList1.setDoubleBuffered(false);
jList1.setNextFocusableComponent(scrollPane);
jList1.setRequestFocusEnabled(true);
jList1.setFixedCellHeight(-1);
jList1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
jList1.setBounds(new Rectangle(0, 0, 104, 114));

this.getContentPane().add(scrollPane, null);
scrollPane.add(jList1);

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ak - 09 Jan 2004 17:38 GMT

you have here many things which are unnecessary:

> scrollPane.setBounds(38,117,120,114);

this is job of LayoutManager

> scrollPane.createVerticalScrollBar();

no need at all (used by ScrollPaneUI implementations to create the vertical
scrollbar - you should override it if you want JScrollPane to use some
subclass of JScrollBar)

> scrollPane.setNextFocusableComponent(jList1);

???

> scrollPane.setEnabled(true);

enabled by default

> jList1.setEnabled(true);

enabled by default

> jList1.setDebugGraphicsOptions(0);

javadoc says: A value of 0 causes no changes to the debugging options.

> jList1.setDoubleBuffered(false);

why?

> jList1.setNextFocusableComponent(scrollPane);

???

> jList1.setRequestFocusEnabled(true);

this is default value

> jList1.setFixedCellHeight(-1);

this is default value

> jList1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

this is default

> jList1.setBounds(new Rectangle(0, 0, 104, 114));

this is job of JScrollPane's LayoutManager

--

____________

http://reader.imagero.com the best java image reader.

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kodonne2 - 08 Jan 2004 20:52 GMT

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xarax - 09 Jan 2004 16:05 GMT

> There is a short example below - I added all of my properties too for each - just in case something I'm doing in JList is nullifing what I'm doing in

JScrollPane or vice versa? Thanks in advance for any help!

> JList jList1;
> JScrollPane scrollPane = new JScrollPane(jList1);
[quoted text clipped - 3 lines]
>
> scrollPane.setBounds(38,117,120,114);

You don't need these:

> scrollPane.setAutoscrolls(true);
> scrollPane.createVerticalScrollBar();
> scrollPane.setWheelScrollingEnabled(true);
> scrollPane.setNextFocusableComponent(jList1);
> scrollPane.setEnabled(true);

> jList1.setEnabled(true);
> jList1.setAutoscrolls(true);

Forget these:

> jList1.setDebugGraphicsOptions(0);
> jList1.setDoubleBuffered(false);
> jList1.setNextFocusableComponent(scrollPane);
> jList1.setRequestFocusEnabled(true);

> jList1.setFixedCellHeight(-1);
> jList1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
> jList1.setBounds(new Rectangle(0, 0, 104, 114));

Don't know what LayoutManager you're using...

> this.getContentPane().add(scrollPane, null);

> scrollPane.add(jList1);

Don't use JScrollPane.add(). Use JScrollPane.setViewportView() instead.

Read the Swing JavaDoc.

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kodonne2 - 08 Jan 2004 21:46 GMT

Okay - I've finally got it!

I took off the scrollBar.add(jList1) at the bottom and made sure that I didn't have more than one declaration of scrollBar. I also didn't define scrollBar until after I added the list to jList1.

if anyone else is having the same problem - e-mail me at the address used in my first post and I can help (this took me so long to figure out that I don't anyone to have to spend this much time if I can help out).

KO

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JScroll not working with JList

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