I am creating and application in Java using Netbeans. I have 1 jFrame on which there is few jmenus and a jdesktoppane and jinternalframes. Now my problem is I am not able to set jInternalFrame at the centre of jDesktopPane. I gor some help from stackoverflow post which is mentioned like this
Dimension desktopSize = desktopPane.getSize();
Dimension jInternalFrameSize = jInternalFrame.getSize();
jInternalFrame.setLocation((desktopSize.width - jInternalFrameSize.width)/2,
(desktopSize.height- jInternalFrameSize.height)/2);
I changed this according to my use like this -
Dimension desktopSize = this.getDesktopPane().getSize(); // Line No. 29
Dimension jInternalFrameSize = this.getSize();
this.setLocation((desktopSize.width - jInternalFrameSize.width)/2,
(desktopSize.height- jInternalFrameSize.height)/2);
But my code is throwing NullPointerException -
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at newUserReg.(newUserReg.java:29) at smsMDI.mnuNewUserActionPerformed(smsMDI.java:278) at smsMDI.access$000(smsMDI.java:16) at smsMDI$2.actionPerformed(smsMDI.java:97) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.AbstractButton.doClick(AbstractButton.java:376) at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833) at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877) at java.awt.Component.processMouseEvent(Component.java:6504) at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) at java.awt.Component.processEvent(Component.java:6269) at java.awt.Container.processEvent(Container.java:2229) at java.awt.Component.dispatchEventImpl(Component.java:4860) at java.awt.Container.dispatchEventImpl(Container.java:2287) at java.awt.Component.dispatchEvent(Component.java:4686) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422) at java.awt.Container.dispatchEventImpl(Container.java:2273) at java.awt.Window.dispatchEventImpl(Window.java:2713) at java.awt.Component.dispatchEvent(Component.java:4686) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707) at java.awt.EventQueue.access$000(EventQueue.java:101) at java.awt.EventQueue$3.run(EventQueue.java:666) at java.awt.EventQueue$3.run(EventQueue.java:664) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87) at java.awt.EventQueue$4.run(EventQueue.java:680) at java.awt.EventQueue$4.run(EventQueue.java:678) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:677) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105) at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
If any one can explain or show me the right way to do this, that will be a great help for me.