/*
* Adjust the width of the scrollpane used by the popup
*/
protected void popupWider(BasicComboPopup popup) {
JList list = popup.getList();
// Determine the maximimum width to use:
// a) determine the popup preferred width
// b) limit width to the maximum if specified
// c) ensure width is not less than the scroll pane width
int popupWidth =
list.getPreferredSize().width
+ 5 // make sure horizontal scrollbar doesn't appear
+ getScrollBarWidth(popup, scrollPane);
if (maximumWidth != -1) {
popupWidth = Math.min(popupWidth, maximumWidth);
}
Dimension scrollPaneSize = scrollPane.getPreferredSize();
popupWidth = Math.max(popupWidth, scrollPaneSize.width);
// Adjust the width
scrollPaneSize.width = popupWidth;
scrollPane.setPreferredSize(scrollPaneSize);
scrollPane.setMaximumSize(scrollPaneSize);
}
/*
* I can't find any property on the scrollBar to determine if it will be
* displayed or not so use brute force to determine this.
*/
protected boolean horizontalScrollBarWillBeVisible(
BasicComboPopup popup, JScrollPane scrollPane) {
JList list = popup.getList();
int scrollBarWidth = getScrollBarWidth(popup, scrollPane);
int popupWidth = list.getPreferredSize().width + scrollBarWidth;
return popupWidth > scrollPane.getPreferredSize().width;
}
protected void customizePopup(BasicComboPopup popup) {
scrollPane = getScrollPane(popup);
if (popupWider) popupWider(popup);
checkHorizontalScrollBar(popup);
// For some reason in JDK7 the popup will not display at its preferred
// width unless its location has been changed from its default
// (ie. for normal "pop down" shift the popup and reset)
Component comboBox = popup.getInvoker();
Point location = comboBox.getLocationOnScreen();
if (popupAbove) {
int height = popup.getPreferredSize().height;
popup.setLocation(location.x, location.y - height);
} else {
int height = comboBox.getPreferredSize().height;
popup.setLocation(location.x, location.y + height - 1);
popup.setLocation(location.x, location.y + height);
}
}
/*
* Get the scroll pane used by the popup so its bounds can be adjusted
*/
protected JScrollPane getScrollPane(BasicComboPopup popup) {
JList list = popup.getList();
Container c = SwingUtilities.getAncestorOfClass(JScrollPane.class, list);
return (JScrollPane) c;
}
/*
* I can't find any property on the scrollBar to determine if it will be
* displayed or not so use brute force to determine this.
*/
protected int getScrollBarWidth(BasicComboPopup popup, JScrollPane scrollPane) {
int scrollBarWidth = 0;
JComboBox comboBox = (JComboBox) popup.getInvoker();
if (comboBox.getItemCount() > comboBox.getMaximumRowCount()) {
JScrollBar vertical = scrollPane.getVerticalScrollBar();
scrollBarWidth = vertical.getPreferredSize().width;
}
return scrollBarWidth;
}
