Implementing a dynamic Scrollable JPopupMenu
Hi,
I wanna make a scrollable JPopupMenu. What I am looking for is I am making a custom popup Menu which extends JPopupMenu. I would be overriding the add method.
I dont want to add a list or a combo box to my JPopupMenu. I want to change the layout itself .. i.e. there is a function in the Container.class which gets called when we try to add a menuitem dynamically to the JPopupMenu
Function Name:
protectedvoid addImpl(Component comp, Object constraints,int index)
Snippet which i am looking in the function
if (layoutMgrinstanceof LayoutManager2){
((LayoutManager2)layoutMgr).addLayoutComponent(comp, constraints);
}
Is there a way while addiing menu items dynamically that I can set the layout to scrollable and hence the menuitems when added are in a scrollpane automatically.. Hence I what i get also is a Scrollable JPopupMenu
# 1
well, this is implementation of PopupMenu with scroll
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GraphicsConfiguration;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.JSeparator;
public class ScrollPopupMenu extends JPopupMenu {
private static final long serialVersionUID = 1;
private JPanel panelMenus = null;
private JScrollPane scroll = null;
public ScrollPopupMenu(GraphicsConfiguration gc) {
super();
scroll = new JScrollPane();
panelMenus = new JPanel();
panelMenus.setLayout(new GridLayout(0,1));
scroll.setViewportView(panelMenus);
scroll.setBorder(null);
scroll.setMaximumSize(new Dimension(scroll.getMaximumSize().width,
this.getToolkit().getScreenSize().height -
this.getToolkit().getScreenInsets(gc).top -
this.getToolkit().getScreenInsets(gc).bottom - 4));
super.add(scroll);
}
public void show(Component invoker, int x, int y) {
this.pack();
panelMenus.validate();
int maxsize = scroll.getMaximumSize().height;
int realsize = panelMenus.getPreferredSize().height;
int sizescroll = 0;
if (maxsize < realsize) {
sizescroll = scroll.getVerticalScrollBar().getPreferredSize().width;
}
scroll.setPreferredSize(new Dimension(
scroll.getPreferredSize().width + sizescroll,
scroll.getPreferredSize().height));
super.show(invoker, x, y);
}
public void add(JButton menuItem) {
panelMenus.add(menuItem);
}
public void addSeparator() {
panelMenus.add(new JSeparator());
}
}
It is very basic, but this to help you, If you want to test, you compile this class:
import javax.swing.SwingUtilities;
import javax.swing.JPanel;
import javax.swing.JFrame;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JLabel;
public class FramePopupMenu extends JFrame {
private static final long serialVersionUID = 1;
private JPanel jContentPane = null;
private JButton btnPopup = null;
private JTextField txtNumElem = null;
private JLabel lblNumElem = null;
private JButton getBtnPopup() {
if (btnPopup == null) {
btnPopup = new JButton();
btnPopup.setText("Ver men?popup");
btnPopup.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ScrollPopupMenu mnu = new ScrollPopupMenu(FramePopupMenu.this.getGraphicsConfiguration());
int n = Integer.parseInt(getTxtNumElem().getText());
for (int i=0;i<n;i++)
mnu.add(new JButton("Men?" + (i+1)));
mnu.show(btnPopup, btnPopup.getWidth(), 0);
}
});
}
return btnPopup;
}
private JTextField getTxtNumElem() {
if (txtNumElem == null) {
txtNumElem = new JTextField();
txtNumElem.setColumns(3);
txtNumElem.setText("60");
}
return txtNumElem;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
FramePopupMenu thisClass = new FramePopupMenu();
thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
thisClass.setVisible(true);
}
});
}
public FramePopupMenu() {
super();
initialize();
}
private void initialize() {
this.setSize(274, 109);
this.setContentPane(getJContentPane());
this.setTitle("Scroll en un men?popup");
}
private JPanel getJContentPane() {
if (jContentPane == null) {
lblNumElem = new JLabel();
lblNumElem.setText("N鷐ero de elementos del Men?);
FlowLayout flowLayout = new FlowLayout();
flowLayout.setHgap(8);
flowLayout.setVgap(8);
jContentPane = new JPanel();
jContentPane.setLayout(flowLayout);
jContentPane.add(getBtnPopup(), null);
jContentPane.add(lblNumElem, null);
jContentPane.add(getTxtNumElem(), null);
}
return jContentPane;
}
}
>
