Help me with Java

Kudzė · December 23, 2015

Hi guys, so I'm making my game in Java JFrame I'm working on button that would exist in jPanel and i get an error:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

at Kudze.SpaceLifeGame.Graphics.Button.updateOnClick(Button.java:71)

at Kudze.SpaceLifeGame.Graphics.Scenes.MainMenuScene.mousePressed(MainMenuScene.java:113)

at Kudze.SpaceLifeGame.Graphics.Scenes.SceneHandler.mousePressed(SceneHandler.java:78)

at Kudze.SpaceLifeGame.Graphics.MainWindow$3.mousePressed(MainWindow.java:106)

at java.awt.Component.processMouseEvent(Unknown Source)

at java.awt.Component.processEvent(Unknown Source)

at java.awt.Container.processEvent(Unknown Source)

at java.awt.Window.processEvent(Unknown Source)

at java.awt.Component.dispatchEventImpl(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$500(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$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.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$JavaSecurityAccessImpl.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)

So strangest thing is that in start it was all working fine, but then I wanted to make my code more optimised and then it worked but when i added another button i get that error

Here's my button code:

package Kudze.SpaceLifeGame.Graphics; import java.awt.Graphics;import java.awt.Image;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.MouseEvent; import javax.swing.SwingUtilities; public class Button extends GraphicsHelper { ActionListener clickListener;Image imageNoHighLight;Image imageYesHighLight; boolean highlighted = false; public boolean isButtonVisible = true;public boolean isButtonActive = true; int Bx = 0;int By = 0;int Bwidth = 0;int Bheight = 0; public Button(Image image, Image imageHighLighted, ActionListener listenerOnClick) {imageNoHighLight = image;imageYesHighLight = imageHighLighted;} /*---------------------------------------------------------------------------------*/ public Image getImageNoHighLight() {return imageNoHighLight;} public Image getImageYesHighLight() {return imageYesHighLight;}  public int getButtonX() {return Bx;} public int getButtonY() {return By;} public int getButtonWidth() {return Bwidth;} public int getButtonHeight() {return Bheight;} /*---------------------------------------------------------------------------------*/  public void update(MouseEvent e) {if(e == null) return; if(e.getX() > Bx && e.getX() < Bx+Bwidth && e.getY() > By+(Bheight/2) && e.getY() < By+(Bheight*1.65)) highlighted = true;else highlighted = false;} public void updateOnClick(MouseEvent e) {if(SwingUtilities.isLeftMouseButton(e) && highlighted == true) {clickListener.actionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, "onButtonClicked")); //Error is here}} /*---------------------------------------------------------------------------------*/ public void draw(Graphics g, int x, int y, int width, int height) {Bx = x;By = y;Bwidth = width;Bheight = height; if(highlighted == true) {g.drawImage(imageYesHighLight, x, y, width, height, null);} else {g.drawImage(imageNoHighLight, x, y, width, height, null);}}}