Opening another JFrame with a button?

Question

This is my code. When I run my program and click btnShop the current frame disposes, but the shop frame doesn't open.

btnShop.addActionListener(new ActionListener() {

                        @Override
                        public void actionPerformed(ActionEvent e) {
                            frame.dispose();
                            Shopframe.setVisible(true);

                                }
                            });``

This is the error I get hen I click the button.

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at MainFrame$6.actionPerformed(MainFrame.java:457)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$400(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

I have been playing around with different methods etc. for over an hour. I just can't get this to work. All I want to do is open the shop frame. Anyone have any ideas as to what I'm doing wrong here?

most likely `ShopFrame` is `null`. You'll have to create the frame before using it. — , May 14 '15 at 20:20
`I did create it.` Please provide more code that includes where/how this is created. — copeg, May 14 '15 at 20:24
apparently you didn't. debug the code, to see if `ShopFrame` is `null`. i bet it is — , May 14 '15 at 20:27
I have a main class and a shop class. The shop frame is created in the shop class, and the shop class extends the main class. — NemoLKLK, May 14 '15 at 20:28
1) See [The Use of Multiple JFrames, Good/Bad Practice?](http://stackoverflow.com/q/9554636/418556) 2) Use a [`CardLayout`](http://download.oracle.com/javase/8/docs/api/java/awt/CardLayout.html) as shown in [this answer](http://stackoverflow.com/a/5786005/418556). 3) For better help sooner, post an [MCVE](http://stackoverflow.com/help/mcve) (Minimal Complete Verifiable Example) or [SSCCE](http://www.sscce.org/) (Short, Self Contained, Correct Example). — Andrew Thompson, May 14 '15 at 20:44
.. 4) See [What is a stack trace, and how can I use it to debug my application errors?](http://stackoverflow.com/q/3988788/418556) & [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/q/218384/418556) — Andrew Thompson, May 14 '15 at 20:45

score 0 · Answer 1 · edited May 14 '15 at 20:46

0

Try on to instantiate the JFrame that you want to open:

btnShop.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        frame.dispose();
        //**add this
        Shopframe name = new ShopFrame();
        //***
        name.setVisible(true);

    }
});

edited May 14 '15 at 20:46

Andrew Thompson

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answered May 14 '15 at 20:26

HolyFav

1

@huseyintugrulbuyukisik It sure doesn't. All of them should run on the Event Dispatch Thread, of which there is only ever one. – Andrew Thompson May 15 '15 at 03:18

Opening another JFrame with a button?

1 Answers1