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POUnknown exception in custom JButton, in java (swing)
 

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  1. POUnknown exception in custom JButton, in java (swing)
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    <p>I have tried to create a custom JButton. I tried to paint its caption via the paintComponent method but i did not like the font rendering of this method. So I added a JLabel to my button which worked fine in first place but after removing the parts for the paintString stuff the compiler throws errors i do not know how to fix/solve. Also what can I improve?</p> <p><strong>The JButtons code:</strong></p> <pre><code>import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.awt.geom.Rectangle2D; class myImageButton extends JButton implements MouseListener { private Color fontColor = new Color(0x222); private Image btn = Toolkit.getDefaultToolkit().getImage("btn.png"); private Image btnHvr = Toolkit.getDefaultToolkit().getImage("btnhvr.png"); private Image btnDwn = Toolkit.getDefaultToolkit().getImage("btndwn.png"); private Image fallback = btn; private Image currentImage = btn; private JFrame parent; private JLabel label; private boolean mouseDown = false; private int captionWidth; private int captionHeight; private Font font = new Font("Open Sans", Font.PLAIN, 12); private FontMetrics fm = new FontMetrics(font) { }; myImageButton(String text, JFrame parent) { parent = parent; Rectangle2D bounds = fm.getStringBounds(text, null); captionWidth = (int) bounds.getWidth(); captionHeight = (int) bounds.getHeight(); addMouseListener(this); setBounds(0,0,79,28); setFont(font); label = new JLabel(text); this.add(label); } public void paintComponent(Graphics g) { g.setColor(parent.getBackground()); g.fillRect(0,0,getWidth(),getHeight()); g.drawImage(currentImage,0,0,parent); //g.setColor(fontColor); //g.drawString(caption, getWidth() / 2 - captionWidth / 2, getHeight() / 2 + captionHeight / 3); } public void paintBorder(Graphics g) { } public void mousePressed(MouseEvent e) { //mouse down currentImage = btnDwn; mouseDown = true; repaint(); } public void mouseReleased(MouseEvent e) { //mouse up currentImage = btnHvr; mouseDown = false; repaint(); } public void mouseEntered(MouseEvent e) { //hover on if (mouseDown) { currentImage = btnDwn; } else { currentImage = btnHvr; } repaint(); } public void mouseExited(MouseEvent e) { //hover off if (mouseDown) { currentImage = btnDwn; } else { currentImage = btn; } repaint(); } public void mouseClicked(MouseEvent e) { //click //should be managed by parent UI class } } </code></pre> <p><strong>The JFrames code:</strong></p> <pre><code>import javax.swing.*; import java.awt.*; import java.awt.event.*; public class Launch { public static void main (String[]args) { JFrame jf = new JFrame(); myImageButton cp = new myImageButton("Exit", jf); jf.setLayout(null); jf.setSize(640,480); jf.setResizable(false); jf.setLocationRelativeTo(null); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jf.add(cp); cp.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { myImageButton_ActionPerformed(evt); } }); cp.setLocation(50,50); jf.setVisible(true); } public static void myImageButton_ActionPerformed(ActionEvent evt) { System.out.println("Click"); } } </code></pre> <p><strong>The full exception stackTrace:</strong></p> <pre><code>Starte C:\Users\Selim\Desktop\Launch.java Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JLayeredPane.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source) at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source) at sun.awt.SunGraphicsCallback.runComponents(Unknown Source) at java.awt.Container.paint(Unknown Source) at java.awt.Window.paint(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JLayeredPane.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source) at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source) at sun.awt.SunGraphicsCallback.runComponents(Unknown Source) at java.awt.Container.paint(Unknown Source) at java.awt.Window.paint(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JLayeredPane.paint(Unknown Source) at javax.swing.JComponent.paintChildren(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent.paint(Unknown Source) at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source) at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source) at sun.awt.SunGraphicsCallback.runComponents(Unknown Source) at java.awt.Container.paint(Unknown Source) at java.awt.Window.paint(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent._paintImmediately(Unknown Source) at javax.swing.JComponent.paintImmediately(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent._paintImmediately(Unknown Source) at javax.swing.JComponent.paintImmediately(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent._paintImmediately(Unknown Source) at javax.swing.JComponent.paintImmediately(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at myImageButton.paintComponent(myImageButton.java:38) at javax.swing.JComponent.paint(Unknown Source) at javax.swing.JComponent.paintToOffscreen(Unknown Source) at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source) at javax.swing.RepaintManager$PaintManager.paint(Unknown Source) at javax.swing.RepaintManager.paint(Unknown Source) at javax.swing.JComponent._paintImmediately(Unknown Source) at javax.swing.JComponent.paintImmediately(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at javax.swing.RepaintManager$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source) at javax.swing.RepaintManager.access$1000(Unknown Source) at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(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.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) </code></pre> <p>Thanks in advance!</p> <p>Selim</p>
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    1. USSelim
    1. USSelim
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    1. CODon't post links to code please, copy the relevant parts to your question.
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      1. POUnknown exception in custom JButton, in java (swing)
      1. USMaroun
    2. COi did thanks for the advice
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      1. POUnknown exception in custom JButton, in java (swing)
      1. USSelim
    3. CONice nested scroll bars :D
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      1. POUnknown exception in custom JButton, in java (swing)
      1. USMaroun
 

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