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| JComboBox<String> combo = new JComboBox<>(items);
class ComboBackgroundListener extends DefaultListCellRenderer implements PopupMenuListener {
private boolean popupVisible;
private Color comboselbg;
@Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
if ( comboselbg==null ) {
comboselbg=list.getSelectionBackground();
list.setSelectionBackground(combo.getBackground());
}
Component c=super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
if ( popupVisible && isSelected ) {
c.setBackground(comboselbg);
}
return c;
}
@Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
popupVisible=true;
}
@Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
popupVisible=false;
}
@Override
public void popupMenuCanceled(PopupMenuEvent e) {
popupVisible=false;
}
};
ComboBackgroundListener renderer = new ComboBackgroundListener();
combo.setRenderer(renderer);
combo.addPopupMenuListener(renderer); |
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