I have a JScrollPane containing a JPanel. I fill this JPanel with many buttons.
Is there any possibility to get the currently shown buttons?
I know I can access the children of a JPanel via jpanel.getComponents()
but those are all components in this pane; I want only the ones that are currently on screen.
As already commented to @mKorbel's answer:
JComponents have an API to get their currently visible part independently of how/where exactly they are currently shown, so the "something" is the JComponent's visibleRect:
Rectangle visibleRect = myPanel.getVisibleRect();
for (Component child : myPanel.getComponents()) {
Rectangle childBounds = child.getBounds();
if (childBounds.intersects(visibleRect)) {
// do stuff
}
}
I assume that this container is already visible on the screen, then I suggest
1) to extract JViewPort from JScrollPane,
2) addChangeListener to JViewPort
3) each visible JComponent(s)
returns Rectangle
4) and Rectangle#intersects returns Boolean
value if is JComponent(s)
visible or not in JViewPort
How about asking the components if they're visible:
for ( Component component : jpanel.getComponents() ) {
if ( component instanceof JButton && component.isShowing() ) {
// We've found a button that is showing...
}
}
Component#isShowing()
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