垂直滚动条 setValue 始终将其设置为 90

Question

I'm saving the state of two scrollbars and loading it with these two methods:

private void saveScrollPosition() {
    scrollY = scrollPane.getVerticalScrollBar().getValue();
    scrollX = scrollPane.getHorizontalScrollBar().getValue();
    System.out.println("Saved: " + scrollX + "," + scrollY);
}

private void loadScrollPosition() {
    scrollPane.getVerticalScrollBar().setValue(scrollY);
    scrollPane.getHorizontalScrollBar().setValue(scrollX);
    System.out.println("Should load: " + scrollX + "," + scrollY);
    System.out.println("Loaded: " + scrollPane.getHorizontalScrollBar().getValue() + "," + scrollPane.getVerticalScrollBar().getValue());
}

The horizontal scrollbar is doing what it is supposed to do but the vertical is always set to 90.

Console:
Saved: 185,882
Should load: 185,882
Loaded: 185,90

Found a tip in a forum to create a new Runnable method and start it with

SwingUtilities.invokeLater(doScroll);

but it didn't work out.

I wonder what I'm doing wrong...

Answer 1

I had to update my contentPane first. Then the vertical scrollbar got updated to the correct values. Idk why it worked with the horizontal scrollbar...

Before:

loadScrollPosition();  
contentPane.updateUI();

After

contentPane.updateUI();
loadScrollPosition();

Hope this helps

Answer 2

I just had the same problem. If somebody still has this problem, here is my situation:

My JScrollPane gets constructed new every time and at this moment the maximum of the VerticalScrollBar was set to 100, so it couldn't accept a higher value.

I fixed it by saving the maximum before constructing the new JScrollPane and then set it to the new Object.

if (scrollPane != null) {
    scrollPos = scrollPane.getVerticalScrollBar().getValue();
    maxScrollPos = scrollPane.getVerticalScrollBar().getMaximum();
}
scrollPane = new JScrollPane(panel);
if (scrollPos != null && maxScrollPos != null) {
    scrollPane.getVerticalScrollBar().setMaximum(maxScrollPos);
    scrollPane.getVerticalScrollBar().setValue(scrollPos);
}