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I have a JScrollPane which contains a JPanel which has large height, This large JPanel contain more Jpanels in it as in the image. Some of those panels contains a JLabel which I used to show titles. At the top, there are JLabels which have numbers matching the title numbers in the title labels. What I need to do is when I click a label from the top label list the JScrollBar should scroll to the position where that label is placed.

I don't know whether this is possible or not, but if anyone know how to scroll to a specific position in a JScrollPane please assist me.

enter image description here

Harsha
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    I have found a solution and It works well what I did is, I get the Y position of the header label I need and then call follwing method of the JScrollPane, jScrollPane.getViewport().setViewPosition(new Point(0, [ Y position of the header label])); – Harsha Aug 24 '12 at 03:08

3 Answers3

9

Assuming you want the whole panel that contains the label as title to be visible:

Container parent = titleLabel.getParent();
parent.scrollRectToVisible(parent.getBounds());

There's no need to access the containing viewport/scrollPane except (there's always an except, isn't it :-)

  • the component the scrollRectToVisible is invoked on has a custom implementation (as f.i. text components
  • if the default location reached by that method isn't up to your liking

Edit

a code snippet for @MadProgrammer :-) - but too lazy to remove every trace of SwingX, so here we go:

final JLabel last = new JLabel("I'm the last");

int maxRow = 20;
int maxColumn = 10;

JComponent content = new JPanel(new GridLayout(maxRow, maxColumn));
for (int row = 0; row < maxRow; row++) {
    for (int column = 0; column < maxColumn; column++) {
        JComponent parent = new JPanel();
        JLabel label = new JLabel("i'm in " + row + "/" + column);
        if (row == (maxRow - 1) && column == (maxColumn - 1)) {
            label = last;
            last.setBorder(BorderFactory.createLineBorder(Color.RED));
        }
        parent.add(label);
        content.add(parent);
    }
}
JXFrame frame = wrapWithScrollingInFrame(content, "scroll");
Action action = new AbstractAction("scrollLastVisible") {

    @Override
    public void actionPerformed(ActionEvent e) {
        last.scrollRectToVisible(last.getBounds());
    }
};
addAction(frame, action);
show(frame, frame.getPreferredSize().width / 2, frame.getPreferredSize().height / 2);
kleopatra
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  • Ahh, I see know, definitely idiot on the out side. I was assuming that the rectangle was relative to the scroll pane. - I'll add that to my little black book of tricks. Thanks (now I feel like deleting my answer :P) – MadProgrammer Aug 24 '12 at 22:52
  • ps I know you don't need it but +1 - shame I can't vote for more ;) – MadProgrammer Aug 24 '12 at 22:58
  • That is not correct. `Container parent = titleLabel.getParent(); parent.scrollRectToVisible(parent.getBounds());` There is no method named scrollRectToVisible on the `Container` class. – searchengine27 Sep 25 '18 at 16:45
  • @searchengine27 yeah, you are right: that's a method on JComponent, needs a type-cast (which is safe enough because we know that we added it to a JPanel). Thanks for the heads-up, feel free to edit with the correction :) – kleopatra Sep 25 '18 at 17:19
7

It's doable.

You will need a reference to the JLabel in the header and where it links to in your view (JPanel). Once you have this link, you can need to determine the location of the JLabel within the 'JPanel'.

You can the use the JViewport.scrollRectToVisible(Rectangle) method to scroll to that location.

JLabel labelInPane = //... reference lookup
Rectangle bounds = labelInPane.getBounds();
// You may need to convert the point to meet the requirements of the parent container...
// bounds.setLocation(SwingUtilities.convertPoint(labelInPane, bounds.getPoint(), topLevelParentPaneInScrollPane));

scrollPane.getViewport().scrollRectToVisible(bounds);
MadProgrammer
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    or change Rectangle directly to JLabels bounds – mKorbel Aug 24 '12 at 05:44
  • @mKorbel You're right...Had it in my head that might have the possibility of moving the viewport so that the label would appear at the bottom of the scroll pane...but obviously that's just crazy talk :P – MadProgrammer Aug 24 '12 at 05:49
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    -1 for overly complicated (tsss ... yet another case of an extremely sticky error ;): label.scrollRectToVisible(label.getBounds()) is all that's needed .. – kleopatra Aug 24 '12 at 08:06
  • @kleopatra of course we're all assuming that the label in question lays on the top level container within the JViewport, if so, then yes, you are both correct & I agree, but if te label was contained in one or more other child containers, I don't believe it would, hence the component about converting the point BUT, you'd not need the view port visible bounds – MadProgrammer Aug 24 '12 at 08:42
  • not a matter of belief - it's a _fact_ the grand-however-deep-children are handled in the default implemenation ;-) – kleopatra Aug 24 '12 at 08:46
  • @kleopatra I'm sorry, I'm obviously just an idiot, but I can't get what you're saying to work (just spent 2 hours playing around with it). I may be misunderstanding what you're trying to say. I layout a `JPanel`, containing 100 `JPanels`, each with a single `JLabel`. Now according to how I understand what you are saying, I should be able to us `JLabel.getBounds` with `scrollRectToVisible` - I couldn't get this to work, in fact the only way I could get it to work was to convert the location of the `Component` with a reference to the viewport and pass that in - Am I missing something obvious :P – MadProgrammer Aug 24 '12 at 12:52
  • something wrong with the code you are not showing Just double-checked: works-for-me (will add a snippet to my answer) – kleopatra Aug 24 '12 at 13:46
  • @kleopatra ps - the problems not with the code, it's with the coder ;) – MadProgrammer Aug 24 '12 at 21:28
3

scrollRectToVisible dont't works for me. But, I solved this way:

AbstractNode a = pkmap.get(0);
scroll.getVerticalScrollBar().setValue(a.getY());
scroll.getHorizontalScrollBar().setValue(a.getX());
Alexandre Zanella
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