Open a window-popup from JMenuItem java

Question

I have a JMenu with a JMenuItem, and when I click on this, I need to open a JFrame or window, in other words a component with inside JButton, JTextField,...

How can i do this ?

Answer 1

You can create the JFrame in the same way you created your initial JFrame, and call

setVisible(true);

in the ActionListener of your JMenuItem to make it visible when the menu is clicked.

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If you want it to be modal (original frame cannot be accessed unless the new window is closed), you can use a JDialog instead, setting modal to true in the constructor, or calling setModal(true).

Answer 2

I write in answer for good code view:

If i use a JFrame i got this error: "java.lang.IllegalArgumentException: adding a window to a container".

That's my code in actionPerformed method:

PopupFactory factory = PopupFactory.getSharedInstance();
JFrame frame = new JFrame();
frame.setLayout(null);
frame.setBounds(428, 99, 185, 155);

final JButton button = new JButton();
button.setText("Button");
button.setBounds(10, 93, 111, 25);
frame.getContentPane().add(button);

final Popup popup = factory.getPopup(null, frame, 200, 200);
popup.show();

Answer 3

You are confusing "popups" and "windows".

A popup is generally shown when you right click on some object. The popup will display a list of actions that can be performed on that object. For example a text field might have "cut", "copy" and "paste". Read the section from the Swing tutorial on "Bringing Up a Popup Menu" for more information.

A window is used to display other Swing components in a JFrame or JDialog.

Given that you are invoking this Action from a menu item I think you probably want to create and display a modal JDialog, not a JFrame or popup.

Also, while reading the tutorial, read the section on "Using Layout Managers". Using null layouts is not the best way to create a dialog.