P-R-W
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How to use Grouplayout in Java
Hello,
On the website from Oracle, there is an example how to use the GroupLayout manager: http://download.oracle.com/javase/tutorial/uiswing/examples/layout/FindProject/src/layout/Find.java
When I run this one in Netbeans it runs fine, but when I want to use it within my program I get a NullPointerException. What I do is, from a menu from another frame I start a new frame with:
Settings settingsFrame = new Settings("Settings");
The Settings class is attached.
What do I forget or what do I do wrong?
Thanks
On the website from Oracle, there is an example how to use the GroupLayout manager: http://download.oracle.com/javase/tutorial/uiswing/examples/layout/FindProject/src/layout/Find.java
When I run this one in Netbeans it runs fine, but when I want to use it within my program I get a NullPointerException. What I do is, from a menu from another frame I start a new frame with:
Settings settingsFrame = new Settings("Settings");
The Settings class is attached.
What do I forget or what do I do wrong?
Thanks
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
import java.awt.event.*;
import java.awt.Component;
import javax.swing.*;
import javax.swing.GroupLayout.*;
public class Settings extends JFrame {
private Alignment LEADING;
private Alignment BASELINE;
public Settings(String titel) {
super(titel);
setVisible(true);
addWindowListener(new VensterHandler());
JLabel label = new JLabel("Find What:");
JTextField textField = new JTextField();
JCheckBox caseCheckBox = new JCheckBox("Match Case");
JCheckBox wrapCheckBox = new JCheckBox("Wrap Around");
JCheckBox wholeCheckBox = new JCheckBox("Whole Words");
JCheckBox backCheckBox = new JCheckBox("Search Backwards");
JButton findButton = new JButton("Find");
JButton cancelButton = new JButton("Cancel");
// remove redundant default border of check boxes - they would hinder
// correct spacing and aligning (maybe not needed on some look and feels)
caseCheckBox.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
wrapCheckBox.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
wholeCheckBox.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
backCheckBox.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
try {
UIManager.setLookAndFeel(
"javax.swing.plaf.metal.MetalLookAndFeel");
// "com.sun.java.swing.plaf.motif.MotifLookAndFeel");
//UIManager.getCrossPlatformLookAndFeelClassName());
} catch (Exception ex) {
ex.printStackTrace();
}
GroupLayout layout = new GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setAutoCreateGaps(true);
layout.setAutoCreateContainerGaps(true);
layout.setHorizontalGroup(layout.createSequentialGroup()
.addComponent(label)
.addGroup(layout.createParallelGroup(LEADING)
.addComponent(textField)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(LEADING)
.addComponent(caseCheckBox)
.addComponent(wholeCheckBox))
.addGroup(layout.createParallelGroup(LEADING)
.addComponent(wrapCheckBox)
.addComponent(backCheckBox))))
.addGroup(layout.createParallelGroup(LEADING)
.addComponent(findButton)
.addComponent(cancelButton))
);
layout.linkSize(SwingConstants.HORIZONTAL, findButton, cancelButton);
layout.setVerticalGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(BASELINE)
.addComponent(label)
.addComponent(textField)
.addComponent(findButton))
.addGroup(layout.createParallelGroup(LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(BASELINE)
.addComponent(caseCheckBox)
.addComponent(wrapCheckBox))
.addGroup(layout.createParallelGroup(BASELINE)
.addComponent(wholeCheckBox)
.addComponent(backCheckBox)))
.addComponent(cancelButton))
);
setTitle("Find");
pack();
}
private class VensterHandler extends WindowAdapter {
public void windowClosing(WindowEvent e) {
dispose();
}
}
}
This is waht I see with that code.
find.PNG
find.PNG
ASKER
Only changed some of the order of the statements. For example, I placed "setVisible(true);" on top. This way, i saw it does create a frame. My guess the problem lies in the fact that I start it from another frame
No, I just placed the main method from find into your code - without any other fram - it still gives error
ASKER
To be a bit more precise: i copied everything into a class I have reused for several other frames. I then took out the bits that I think i don't need. For example the public static void main(String args[]). When I got the error, i started to shuffle a bit to see if it would go further, but no luck. The error I get is:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep tion
at javax.swing.GroupLayout$Pa rallelGrou p.setChild Size(Group Layout.jav a:2523)
at javax.swing.GroupLayout$Pa rallelGrou p.setValid Size(Group Layout.jav a:2511)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1977)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1977)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout.ca lculateAut opadding(G roupLayout .java:1058 )
at javax.swing.GroupLayout.pr epare(Grou pLayout.ja va:1037)
at javax.swing.GroupLayout.pr eferredLay outSize(Gr oupLayout. java:857)
at java.awt.Container.preferr edSize(Con tainer.jav a:1616)
at java.awt.Container.getPref erredSize( Container. java:1601)
at javax.swing.JComponent.get PreferredS ize(JCompo nent.java: 1629)
at javax.swing.JRootPane$Root Layout.pre ferredLayo utSize(JRo otPane.jav a:903)
at java.awt.Container.preferr edSize(Con tainer.jav a:1616)
at java.awt.Container.getPref erredSize( Container. java:1601)
at javax.swing.JComponent.get PreferredS ize(JCompo nent.java: 1629)
at java.awt.BorderLayout.pref erredLayou tSize(Bord erLayout.j ava:702)
at java.awt.Container.preferr edSize(Con tainer.jav a:1616)
at java.awt.Container.getPref erredSize( Container. java:1601)
at java.awt.Window.pack(Windo w.java:665 )
at General.Settings.<init>(Se ttings.jav a:95)
at tech2.Menu$settingsHandler .actionPer formed(Men u.java:161 )
at javax.swing.AbstractButton .fireActio nPerformed (AbstractB utton.java :1995)
at javax.swing.AbstractButton $Handler.a ctionPerfo rmed(Abstr actButton. java:2318)
at javax.swing.DefaultButtonM odel.fireA ctionPerfo rmed(Defau ltButtonMo del.java:3 87)
at javax.swing.DefaultButtonM odel.setPr essed(Defa ultButtonM odel.java: 242)
at javax.swing.AbstractButton .doClick(A bstractBut ton.java:3 57)
at javax.swing.plaf.basic.Bas icMenuItem UI.doClick (BasicMenu ItemUI.jav a:1170)
at javax.swing.plaf.basic.Bas icMenuItem UI$Handler .mouseRele ased(Basic MenuItemUI .java:1211 )
at java.awt.Component.process MouseEvent (Component .java:6038 )
at javax.swing.JComponent.pro cessMouseE vent(JComp onent.java :3260)
at java.awt.Component.process Event(Comp onent.java :5803)
at java.awt.Container.process Event(Cont ainer.java :2058)
at java.awt.Component.dispatc hEventImpl (Component .java:4410 )
at java.awt.Container.dispatc hEventImpl (Container .java:2116 )
at java.awt.Component.dispatc hEvent(Com ponent.jav a:4240)
at java.awt.LightweightDispat cher.retar getMouseEv ent(Contai ner.java:4 322)
at java.awt.LightweightDispat cher.proce ssMouseEve nt(Contain er.java:39 86)
at java.awt.LightweightDispat cher.dispa tchEvent(C ontainer.j ava:3916)
at java.awt.Container.dispatc hEventImpl (Container .java:2102 )
at java.awt.Window.dispatchEv entImpl(Wi ndow.java: 2429)
at java.awt.Component.dispatc hEvent(Com ponent.jav a:4240)
at java.awt.EventQueue.dispat chEvent(Ev entQueue.j ava:599)
at java.awt.EventDispatchThre ad.pumpOne EventForFi lters(Even tDispatchT hread.java :273)
at java.awt.EventDispatchThre ad.pumpEve ntsForFilt er(EventDi spatchThre ad.java:18 3)
at java.awt.EventDispatchThre ad.pumpEve ntsForHier archy(Even tDispatchT hread.java :173)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 68)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 60)
at java.awt.EventDispatchThre ad.run(Eve ntDispatch Thread.jav a:121)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep tion
at javax.swing.GroupLayout$Pa rallelGrou p.setChild Size(Group Layout.jav a:2523)
at javax.swing.GroupLayout$Pa rallelGrou p.setValid Size(Group Layout.jav a:2511)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1977)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSizeNotP referred(G roupLayout .java:2059 )
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1987)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout.ca lculateAut opadding(G roupLayout .java:1058 )
at javax.swing.GroupLayout.la youtContai ner(GroupL ayout.java :897)
at java.awt.Container.layout( Container. java:1432)
at java.awt.Container.doLayou t(Containe r.java:142 1)
at java.awt.Container.validat eTree(Cont ainer.java :1519)
at java.awt.Container.validat eTree(Cont ainer.java :1526)
at java.awt.Container.validat eTree(Cont ainer.java :1526)
at java.awt.Container.validat eTree(Cont ainer.java :1526)
at java.awt.Container.validat e(Containe r.java:149 1)
at java.awt.Window.dispatchEv entImpl(Wi ndow.java: 2427)
at java.awt.Component.dispatc hEvent(Com ponent.jav a:4240)
at java.awt.EventQueue.dispat chEvent(Ev entQueue.j ava:599)
at java.awt.EventDispatchThre ad.pumpOne EventForFi lters(Even tDispatchT hread.java :273)
at java.awt.EventDispatchThre ad.pumpEve ntsForFilt er(EventDi spatchThre ad.java:18 3)
at java.awt.EventDispatchThre ad.pumpEve ntsForHier archy(Even tDispatchT hread.java :173)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 68)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 60)
at java.awt.EventDispatchThre ad.run(Eve ntDispatch Thread.jav a:121)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep tion
at javax.swing.GroupLayout$Pa rallelGrou p.setChild Size(Group Layout.jav a:2523)
at javax.swing.GroupLayout$Pa rallelGrou p.setValid Size(Group Layout.jav a:2511)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1977)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSizeNotP referred(G roupLayout .java:2059 )
at javax.swing.GroupLayout$Se quentialGr oup.setVal idSize(Gro upLayout.j ava:1987)
at javax.swing.GroupLayout$Gr oup.setSiz e(GroupLay out.java:1 553)
at javax.swing.GroupLayout.ca lculateAut opadding(G roupLayout .java:1058 )
at javax.swing.GroupLayout.la youtContai ner(GroupL ayout.java :897)
at java.awt.Container.layout( Container. java:1432)
at java.awt.Container.doLayou t(Containe r.java:142 1)
at java.awt.Container.validat eTree(Cont ainer.java :1519)
at java.awt.Container.validat eTree(Cont ainer.java :1526)
at java.awt.Container.validat eTree(Cont ainer.java :1526)
at java.awt.Container.validat e(Containe r.java:149 1)
at javax.swing.RepaintManager .validateI nvalidComp onents(Rep aintManage r.java:639 )
at javax.swing.SystemEventQue ueUtilitie s$Componen tWorkReque st.run(Sys temEventQu eueUtiliti es.java:12 7)
at java.awt.event.InvocationE vent.dispa tch(Invoca tionEvent. java:209)
at java.awt.EventQueue.dispat chEvent(Ev entQueue.j ava:597)
at java.awt.EventDispatchThre ad.pumpOne EventForFi lters(Even tDispatchT hread.java :273)
at java.awt.EventDispatchThre ad.pumpEve ntsForFilt er(EventDi spatchThre ad.java:18 3)
at java.awt.EventDispatchThre ad.pumpEve ntsForHier archy(Even tDispatchT hread.java :173)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 68)
at java.awt.EventDispatchThre ad.pumpEve nts(EventD ispatchThr ead.java:1 60)
at java.awt.EventDispatchThre ad.run(Eve ntDispatch Thread.jav a:121)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout.ca
at javax.swing.GroupLayout.pr
at javax.swing.GroupLayout.pr
at java.awt.Container.preferr
at java.awt.Container.getPref
at javax.swing.JComponent.get
at javax.swing.JRootPane$Root
at java.awt.Container.preferr
at java.awt.Container.getPref
at javax.swing.JComponent.get
at java.awt.BorderLayout.pref
at java.awt.Container.preferr
at java.awt.Container.getPref
at java.awt.Window.pack(Windo
at General.Settings.<init>(Se
at tech2.Menu$settingsHandler
at javax.swing.AbstractButton
at javax.swing.AbstractButton
at javax.swing.DefaultButtonM
at javax.swing.DefaultButtonM
at javax.swing.AbstractButton
at javax.swing.plaf.basic.Bas
at javax.swing.plaf.basic.Bas
at java.awt.Component.process
at javax.swing.JComponent.pro
at java.awt.Component.process
at java.awt.Container.process
at java.awt.Component.dispatc
at java.awt.Container.dispatc
at java.awt.Component.dispatc
at java.awt.LightweightDispat
at java.awt.LightweightDispat
at java.awt.LightweightDispat
at java.awt.Container.dispatc
at java.awt.Window.dispatchEv
at java.awt.Component.dispatc
at java.awt.EventQueue.dispat
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout.ca
at javax.swing.GroupLayout.la
at java.awt.Container.layout(
at java.awt.Container.doLayou
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Window.dispatchEv
at java.awt.Component.dispatc
at java.awt.EventQueue.dispat
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExcep
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Pa
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Se
at javax.swing.GroupLayout$Gr
at javax.swing.GroupLayout.ca
at javax.swing.GroupLayout.la
at java.awt.Container.layout(
at java.awt.Container.doLayou
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Container.validat
at java.awt.Container.validat
at javax.swing.RepaintManager
at javax.swing.SystemEventQue
at java.awt.event.InvocationE
at java.awt.EventQueue.dispat
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
at java.awt.EventDispatchThre
ASKER CERTIFIED SOLUTION
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ASKER
Thanks a lot! This worked. Can you also tell me why? I followed the import suggestions from Netbeans.
This one very similar form
http://download.oracle.com/javase/tutorial/uiswing/examples/layout/FindProject/src/layout/Find.java
works for me outside of Netbeans.
What did you change?
Open in new window