javax.swing.plaf.basic.BasicComboPopup#getInvoker ( )源码实例Demo

private 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);
        //TODO should not be hardcoded
        popup.setLocation(location.x + 5, location.y + 35);
    }
}
 

protected void customizePopup(BasicComboPopup popup) {
  scrollPane = getScrollPane(popup);
  popupWider(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();

  int height = comboBox.getSize().height;
  popup.setLocation(location.x, location.y + height - 1);
  popup.setLocation(location.x, location.y + height);
}
 

protected int getScrollBarWidth(BasicComboPopup popup, JScrollPane scrollPane) {
  // 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.
  JComboBox<?> comboBox = (JComboBox) popup.getInvoker();

  if (comboBox.getItemCount() > comboBox.getMaximumRowCount()) {
    return scrollPane.getVerticalScrollBar().getPreferredSize().width;
  }
  else {
    return 0;
  }
}
 

private int getScrollBarWidth(BasicComboPopup popup, JScrollPane scrollPane) {
    int scrollBarWidth = 0;
    @SuppressWarnings("unchecked")
    JComboBox<E> comboBox = (JComboBox<E>) popup.getInvoker();

    if (comboBox.getItemCount() > comboBox.getMaximumRowCount()) {
        JScrollBar vertical = scrollPane.getVerticalScrollBar();
        scrollBarWidth = vertical.getPreferredSize().width;
    }

    return scrollBarWidth;
}