Πρόβλημα σε πρόγραμμα JAVA!

LeoPao13 · 25 Μαΐου 2012

Γεια σας! Είμαι καινούριος στην Java και δεν μπορώ να βρω τι πρόβλημα έχει το πρόγραμμα που εχω φτιάξει για εργασία στην σχολή..Όταν το εκτελώ μου βγάζει

run:

Exception in thread "main" java.lang.NullPointerException

at java.awt.Container.addImpl(Container.java:1090)

at java.awt.Container.add(Container.java:410)

at javax.swing.JPopupMenu.add(JPopupMenu.java:288)

at javax.swing.JMenu.add(JMenu.java:579)

at myfirsteditor.Myfirsteditor.<init>(Myfirsteditor.java:96)

at myfirsteditor.Myfirsteditor.main(Myfirsteditor.java:55)

Java Result: 1

BUILD SUCCESSFUL (total time: 1 second)

Ο κώδικας είναι:

>package myfirsteditor;
/**
*
* @author
*  
*/
import java.awt.event.*;
import java.awt.*;
import javax.swing.event.*;
import javax.swing.*;
import java.io.*;
import java.lang.*;

public class Myfirsteditor extends JFrame{
   Container cp;
   JMenuBar menuBar;
   JMenu fileMenu, settingsMenu;
   JMenuItem fileNew,fileOpen,fileSave,fileExit;
   JMenuItem editCopy,editPaste,editCut;
   JMenuItem settingsUppercase,settingsLowercase;
   MenuItemHandler handler;
   
   JFileChooser chooser;
   File file;
   FileReader input;
   FileWriter output;
   BufferedReader reader;
   
   GridLayout gl;
   JPanel p1,p2,p3;
   JTextField tf1,tf2;
   JTextArea ta;
   JComboBox combo;
   JList list;
   JScrollPane ScrollPaneArea;
   JButton b1;
   
   ActionListener handle=new ButtonHandler();
   JRadioButton rb1,rb2,rb3,rb4,rb5,rb6;
   ButtonGroup radio,radio1;    
   
   Font f;
   String vFont="TimesRoman";
   int vSize=14;
   int vBold=Font.PLAIN;
   int vItalic=Font.PLAIN;
   int character;
   String vIType1=Font.SERIF;
   String mFonts[];
   String numbers[]={"6","8","10","12","14","16","18","20","22","24"};
   int size[]={6,8,10,12,14,16,18,20,22,24};
   
   public static void main(String[] args) {
       Myfirsteditor Editor  = new Myfirsteditor();
       Editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       Editor.setSize(400,500);
       Editor.setLocation(200, 200);
       Editor.setResizable(false);
       Editor.setVisible(true);
   }
   
public Myfirsteditor()
{
   super("Editor");
   MenuItemHandler handlers=new MenuItemHandler();
   menuBar=new JMenuBar();
   //1
   fileMenu=new JMenu("File");
   fileNew=new JMenuItem("New");
   fileNew.addActionListener(handlers);
   fileMenu.add(fileNew);
   //2
   fileOpen=new JMenuItem("Open");
   fileOpen.addActionListener(handlers);
   fileMenu.add(fileOpen);
   //3
   fileSave=new JMenuItem("Save");
   fileSave.addActionListener(handlers);
   fileMenu.add(fileSave);
   //4
   fileExit=new JMenuItem("Exit");
   fileExit.addActionListener(handlers);
   fileMenu.add(fileExit);
   
   menuBar.add(fileMenu);
   
   settingsMenu=new JMenu("Edit");
   //1
   editCopy=new JMenuItem("Copy");
   editCopy.addActionListener(handlers);
   settingsMenu.add(editCopy);
   //2
   editCut=new JMenuItem("Paste");
   editCut.addActionListener(handlers);
   settingsMenu.add(editPaste);
   //3
   editPaste=new JMenuItem("Cut");
   editPaste.addActionListener(handlers);
   settingsMenu.add(editCut);
   
   menuBar.add(settingsMenu);
   
   JPanel panel=new JPanel(new BorderLayout());
   //tf1=new JTextField(20);
   //pl.add(tf1,BorderLayout.SOUTH);
   //cp.add(pl,BorderLayout.SOUTH);
   setJMenuBar(menuBar);
   
   ComboHandler handler1=new ComboHandler();
   ListHandler handler2=new ListHandler();
   CheckRadioHandler handler3=new CheckRadioHandler();
   
   cp=getContentPane();
   gl=new GridLayout(4,1);
   cp.setLayout(gl);
   
   //Πρώτο πάνελ με το πεδίο κειμένου
   p1=new JPanel();
   tf2=new JTextField("This is the text:",20);
   
   //Δημιούργησε μία περιοχή κειμένου
   ta=new JTextArea("Write a word...");
   ta.setFont(new Font("Serif", Font.ITALIC, 16));
   ta.setLineWrap(true);    //Επιτρεπτή αναδίπλωση γραμμής κειμένου
   ta.setWrapStyleWord(true); //Επιτρεπτή αναδίπλωση λέξης
   
   ta.setBorder(
           BorderFactory.createCompoundBorder(
               BorderFactory.createCompoundBorder(
                               BorderFactory.createTitledBorder("Write your text"),
                               BorderFactory.createEmptyBorder(4,4,4,4)),
               ta.getBorder()));
   
   ScrollPaneArea = new JScrollPane(ta);
   ScrollPaneArea.setVerticalScrollBarPolicy(
                 JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
   ScrollPaneArea.setPreferredSize(new Dimension(250, 250));
   BorderFactory.createCompoundBorder(
                 BorderFactory.createCompoundBorder(
                               BorderFactory.createTitledBorder("Text Area"),
                               BorderFactory.createEmptyBorder(4,4,4,4)),
               ScrollPaneArea.getBorder());
   
   p1.add(tf2);
   p1.add(ta);
   p1.add(ScrollPaneArea);
   
   //Δεύτερο πάνελ με τα RadioButtons
   radio=new ButtonGroup();
   p2=new JPanel();
   rb1=new JRadioButton("TimesRoman 14",true);
   rb2=new JRadioButton("Arial 10",false);
   rb3=new JRadioButton("Courier 18",false);
   combo=new JComboBox(numbers);//
   combo.setMaximumRowCount(3);//
   
   radio.add(rb1);
   radio.add(rb2);
   radio.add(rb3);
   rb1.addItemListener(handler3);
   rb2.addItemListener(handler3);
   rb3.addItemListener(handler3);
   combo.addItemListener(handler1);
   
   GraphicsEnvironment env =GraphicsEnvironment.getLocalGraphicsEnvironment();
   mFonts=env.getAvailableFontFamilyNames();
   
   list =new JList(mFonts);
   list.setVisibleRowCount(4);
   list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
   list.addListSelectionListener(handler2);
   ScrollPaneArea=new JScrollPane(list);
   
   p2.add(rb1);
   p2.add(rb2);
   p2.add(rb3);
   p2.add(combo);
   p2.add(ScrollPaneArea);
   
   //Τρίτο πάνελ
   radio1=new ButtonGroup();
   p3=new JPanel();
   rb4=new JRadioButton("Πράσινο",true);
   rb5=new JRadioButton("Κόκκινο",false);
   rb6=new JRadioButton("Μπλε",false);
   radio1.add(rb4);
   radio1.add(rb5);
   radio1.add(rb6);
   rb4.addItemListener(handler3);
   rb5.addItemListener(handler3);
   rb6.addItemListener(handler3);
   p3.add(rb4);
   p3.add(rb5);
   p3.add(rb6);
   
   //Τρίτο πανελ
   p3=new JPanel();
   b1=new JButton("Καρκινική;");
   b1.addActionListener(handle);//
   p3.add(b1);
   cp=getContentPane();
   gl=new GridLayout(4,1);
   cp.setLayout(gl);

   cp.add(p1);
   cp.add(p2);
   cp.add(p3);
   panel.add(tf2,BorderLayout.SOUTH);
     cp.add(tf2,BorderLayout.SOUTH);
}
   
   private class ListHandler implements ListSelectionListener{
       @Override
    public void valueChanged(ListSelectionEvent e){
        vFont=mFonts[list.getSelectedIndex()];
          f=new Font(vFont,vBold+vItalic,vSize);
          tf2.setFont(f);
          ta.setFont(f);
             ta.repaint();
          tf2.repaint();
    }

 }
   private class ComboHandler implements ItemListener{
       @Override
    public void itemStateChanged(ItemEvent e){
        vSize=size[combo.getSelectedIndex()];
          f=new Font(vFont,vBold+vItalic,vSize);
          tf2.setFont(f);
          tf2.repaint();
          ta.setFont(f);
             ta.repaint();
    }

 }
   private class CheckRadioHandler implements ItemListener{
       @Override
    public void itemStateChanged(ItemEvent e){
      if (e.getSource()==rb4)
           ta.setForeground(Color.GREEN);
      
       else if (e.getSource()==rb5)
           ta.setForeground(Color.RED);
       
       else if (e.getSource()==rb6)
           ta.setForeground(Color.BLUE);
       
      else if (e.getSource()==rb1)
        {vFont="TimesRoman";vSize=14;}

      else if (e.getSource()==rb2)
        {vFont="Arial";vSize=10;}

      else if (e.getSource()==rb3)
        {vFont="Courier";vSize=18;}

      f=new Font(vFont+vIType1,vBold+vItalic,vSize);
      tf2.setFont(f);
      tf2.repaint();
      ta.setFont(f);
      ta.repaint();
      }
  }
   class MenuItemHandler implements ActionListener {
       @Override
     public void actionPerformed(ActionEvent e){
       if (e.getSource() ==fileExit)
         System.exit(0);
       else if (e.getSource()==fileOpen)
        {int result=chooser.showOpenDialog(null);
         String s=chooser.getSelectedFile().getPath();
         
      JOptionPane.showMessageDialog(null, "Choose:" + s,"Results",JOptionPane.INFORMATION_MESSAGE);
      
      try{
          file=new File(s);
          input=new FileReader(file);
      reader=new BufferedReader(input);
      //output=new FileWriter(file);
      String line;
      line=reader.readLine();
      while(line !=null){
          System.out.println(line);
          line=reader.readLine();
      }
      reader.close();
      //output.close();
      }

      catch(Exception exc) {
         System.out.println("ERROR");
      }
      }
      else if (e.getSource()==fileSave)
      { int result=chooser.showSaveDialog(null);
        String s=chooser.getSelectedFile().getPath();
        JOptionPane.showMessageDialog(null, "Choose:" + s,"Results",JOptionPane.INFORMATION_MESSAGE);

       try{
          file=new File(s);
          output=new FileWriter(file);
          String tar=ta.getText();
          output.write(tar);
          output.close();
          }
     catch(Exception exc) {
          System.out.println("ERROR");
          String cmd=e.getActionCommand();
          tf2.setText(cmd);
       }
     }
     }
   }
   class ButtonHandler implements ActionListener {
       @Override
     public void actionPerformed(ActionEvent evt) {
       System.out.println ("The current text is: " + evt.getActionCommand());
       if (evt.getSource() instanceof TextField) {
           TextField tf2 = (TextField)evt.getSource();
           StringBuffer sb = new StringBuffer (evt.getActionCommand());
           ta.setText (sb.reverse().toString());
           }
       }
   }
}

pantpesl2 · 25 Μαΐου 2012

Καλησπέρα φίλε μου, αυτό που παρατήρησα είναι ότι έχεις "ανακατέψει" λίγο το cut με το paste.

>
//2
editCut=new JMenuItem("Cut");
editCut.addActionListener(handlers);
settingsMenu.add(editCut);
//3
editPaste=new JMenuItem("Paste");
editPaste.addActionListener(handlers);
settingsMenu.add(editPaste);

Το λάθος είναι στο ότι χρησιμοποίησες το editPaste πριν το αρχικοποιήσεις (settingsMenu.add(editPaste).

LeoPao13 · 25 Μαΐου 2012

Καλησπέρα φίλε μου, αυτό που παρατήρησα είναι ότι έχεις "ανακατέψει" λίγο το cut με το paste.
>
//2
editCut=new JMenuItem("Cut");
editCut.addActionListener(handlers);
settingsMenu.add(editCut);
//3
editPaste=new JMenuItem("Paste");
editPaste.addActionListener(handlers);
settingsMenu.add(editPaste);
Το λάθος είναι στο ότι χρησιμοποίησες το editPaste πριν το αρχικοποιήσεις (settingsMenu.add(editPaste).

Σωστό..το λάθος ήταν τελικα στους handlers! Τώρα δουλεύει

Το σωστό..

>package myfirsteditor;
/**
*
* @author 
* 
*/
import java.awt.event.*;
import java.awt.*;
import javax.swing.event.*;
import javax.swing.*;
import java.io.*;

public class Myfirsteditor extends JFrame{
Container cp;
JMenuBar menuBar;
JMenu fileMenu,editMenu,settingsMenu,helpMenu;
JMenuItem fileNew,fileOpen,fileSave,fileExit;
JMenuItem editCopy,editPaste,editCut;
JMenuItem settingsUppercase,settingsLowercase;
JMenuItem helpTutorial,helpOnline;
Myfirsteditor.MenuItemHandler handler;

JFileChooser chooser;
File file;
FileReader input;
FileWriter output;
BufferedReader reader;

GridLayout gl;
JPanel p1,p2,p3,p4;
JTextField tf1,tf2;
JTextArea ta;
JComboBox combo;
JList list;
JScrollPane ScrollPaneArea;
JButton b1;
StringBuffer sb;
ActionListener handle=new Myfirsteditor.ButtonHandler();
JRadioButton rb1,rb2,rb3,rb4,rb5,rb6;
ButtonGroup radio,radio1;

Font f;
String vFont="TimesRoman";
int vSize=14;
int vBold=Font.PLAIN;
int vItalic=Font.PLAIN;
int character;
String vIType1=Font.SERIF;
String mFonts[];
String numbers[]={"6","8","10","12","14","16","18","20","22","24"};
int size[]={6,8,10,12,14,16,18,20,22,24};

public static void main(String[] args) {
   Myfirsteditor Editor = new Myfirsteditor();
   Editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   Editor.setSize(400,500);
   Editor.setLocation(200, 200);
   //Editor.setResizable(false);
   Editor.setVisible(true);
}

public Myfirsteditor ()
{
   super("Editor");
   Myfirsteditor.MenuItemHandler handlers=new Myfirsteditor.MenuItemHandler();
   menuBar=new JMenuBar();
//1
   fileMenu=new JMenu("File");
   fileNew=new JMenuItem("New");
   fileNew.addActionListener(handlers);
   fileMenu.add(fileNew);
//2
   fileOpen=new JMenuItem("Open");
   fileOpen.addActionListener(handlers);
   fileMenu.add(fileOpen);
//3
   fileSave=new JMenuItem("Save");
   fileSave.addActionListener(handlers);
   fileMenu.add(fileSave);
//4
   fileExit=new JMenuItem("Exit");
   fileExit.addActionListener(handlers);
   fileMenu.add(fileExit);

   menuBar.add(fileMenu);

   editMenu=new JMenu("Edit");
//1
   editCopy=new JMenuItem("Copy");
   editCopy.addActionListener(handlers);
   editMenu.add(editCopy);
//2
   editCut=new JMenuItem("Cut");
   editCut.addActionListener(handlers);
   editMenu.add(editCut);
//3
   editPaste=new JMenuItem("Paste");
   editMenu.addSeparator();
   editPaste.addActionListener(handlers);
   editMenu.add(editPaste);
   

   menuBar.add(editMenu);
   
   settingsMenu=new JMenu("Settings");
//1
   settingsUppercase=new JMenuItem("Uppercase");
   settingsUppercase.addActionListener(handlers);
   settingsMenu.add(settingsUppercase);
//2
   settingsLowercase=new JMenuItem("Lowercase");
   settingsLowercase.addActionListener(handlers);
   settingsMenu.add(settingsLowercase);
   
   menuBar.add(settingsMenu);
   
   helpMenu=new JMenu("Help");
   
   helpTutorial=new JMenuItem("Tutorial");
   helpTutorial.addActionListener(handlers);
   helpMenu.add(helpTutorial);
   
   helpOnline=new JMenuItem("Online");
   helpOnline.addActionListener(handlers);
   helpMenu.add(helpOnline);
   
   menuBar.add(helpMenu);

   JPanel panel=new JPanel(new BorderLayout());
   //tf1=new JTextField(20);
   //pl.add(tf1,BorderLayout.SOUTH);
   //cp.add(pl,BorderLayout.SOUTH);
   setJMenuBar(menuBar);
   
Myfirsteditor.ComboHandler handler1=new Myfirsteditor.ComboHandler();
Myfirsteditor.ListHandler handler2=new Myfirsteditor.ListHandler();
Myfirsteditor.CheckRadioHandler handler3=new Myfirsteditor.CheckRadioHandler();

cp=getContentPane();
gl=new GridLayout(6,1);
cp.setLayout(gl);

//Πρώτο πάνελ με το πεδίο κειμένου
p1=new JPanel();
tf2=new JTextField("This is the text:",20);

//Δημιούργησε μία περιοχή κειμένου
ta=new JTextArea("Καρκινική λέξη...");
ta.setFont(new Font("Serif", Font.ITALIC, 16));
ta.setLineWrap(true); //Επιτρεπτή αναδίπλωση γραμμής κειμένου
ta.setWrapStyleWord(true); //Επιτρεπτή αναδίπλωση λέξης

ta.setBorder(
   BorderFactory.createCompoundBorder(
   BorderFactory.createCompoundBorder(
   BorderFactory.createTitledBorder("Text given"),
   BorderFactory.createEmptyBorder(4,4,4,4)),
ta.getBorder()));

ScrollPaneArea = new JScrollPane(ta);
   ScrollPaneArea.setVerticalScrollBarPolicy(
   JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
ScrollPaneArea.setPreferredSize(new Dimension(50,75));
   BorderFactory.createCompoundBorder(
   BorderFactory.createCompoundBorder(
   BorderFactory.createTitledBorder("Text Area"),
   BorderFactory.createEmptyBorder(4,4,4,4)),
ScrollPaneArea.getBorder());

p1.add(tf2);
p1.add(ta);
p1.add(ScrollPaneArea);

//Δεύτερο πάνελ με τα RadioButtons
radio=new ButtonGroup();
p2=new JPanel();
rb1=new JRadioButton("TimesRoman 14",true);
rb2=new JRadioButton("Arial 10",false);
rb3=new JRadioButton("Courier 18",false);
combo=new JComboBox(numbers);//
combo.setMaximumRowCount(3);//

radio.add(rb1);
radio.add(rb2);
radio.add(rb3);
rb1.addItemListener(handler3);
rb2.addItemListener(handler3);
rb3.addItemListener(handler3);
combo.addItemListener(handler1);

GraphicsEnvironment env =GraphicsEnvironment.getLocalGraphicsEnvironment();
mFonts=env.getAvailableFontFamilyNames();

list =new JList(mFonts);
list.setVisibleRowCount(4);
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.addListSelectionListener(handler2);
ScrollPaneArea=new JScrollPane(list);

p2.add(rb1);
p2.add(rb2);
p2.add(rb3);
p2.add(combo);
p2.add(ScrollPaneArea);

//Τρίτο πάνελ
radio1=new ButtonGroup();
//p3=new JPanel();
p4=new JPanel();
rb4=new JRadioButton("Πράσινο",true);
rb5=new JRadioButton("Κόκκινο",false);
rb6=new JRadioButton("Μπλε",false);
radio1.add(rb4);
radio1.add(rb5);
radio1.add(rb6);
rb4.addItemListener(handler3);
rb5.addItemListener(handler3);
rb6.addItemListener(handler3);
p4.add(rb4);
p4.add(rb5);
p4.add(rb6);

//Τρίτο πανελ
p3=new JPanel();
b1=new JButton("Καρκινική;");
b1.addActionListener(handle);//
p3.add(b1);

cp=getContentPane();
gl=new GridLayout(4,1);
cp.setLayout(gl);

cp.add(p1);
cp.add(p2);
cp.add(p3);
cp.add(p4);

panel.add(tf2,BorderLayout.SOUTH);
cp.add(tf2,BorderLayout.SOUTH);
}

private class ListHandler implements ListSelectionListener{
@Override
   public void valueChanged(ListSelectionEvent e){
       vFont=mFonts[list.getSelectedIndex()];
       f=new Font(vFont,vBold+vItalic,vSize);
       tf2.setFont(f);
       ta.setFont(f);
       ta.repaint();
       tf2.repaint();
       }
}

private class ComboHandler implements ItemListener{
@Override
   public void itemStateChanged(ItemEvent e){
       vSize=size[combo.getSelectedIndex()];
       f=new Font(vFont,vBold+vItalic,vSize);
       tf2.setFont(f);
       tf2.repaint();
       ta.setFont(f);
       ta.repaint();
       }
}

private class CheckRadioHandler implements ItemListener{
@Override
   public void itemStateChanged(ItemEvent e){
   if (e.getSource()==rb4)
       ta.setForeground(Color.GREEN);

   else if (e.getSource()==rb5)
       ta.setForeground(Color.RED);

   else if (e.getSource()==rb6)
       ta.setForeground(Color.BLUE);

   else if (e.getSource()==rb1)
       {vFont="TimesRoman";vSize=14;}

   else if (e.getSource()==rb2)
       {vFont="Arial";vSize=10;}

   else if (e.getSource()==rb3)
       {vFont="Courier";vSize=18;}

f=new Font(vFont+vIType1,vBold+vItalic,vSize);
tf2.setFont(f);
tf2.repaint();
ta.setFont(f);
ta.repaint();
 }
}

class MenuItemHandler implements ActionListener {
@Override
   public void actionPerformed(ActionEvent e){
   if (e.getSource() ==fileExit)
       System.exit(0);
   else if (e.getSource()==fileOpen)
       {int result=chooser.showOpenDialog(null);
   String s=chooser.getSelectedFile().getPath();

JOptionPane.showMessageDialog(null, "Choose:" + s,"Results",JOptionPane.INFORMATION_MESSAGE);

try{
       file=new File(s);
       input=new FileReader(file);
       reader=new BufferedReader(input);
       //output=new FileWriter(file);
       String line;
       line=reader.readLine();
       while(line !=null){
           System.out.println(line);
           line=reader.readLine();
       }
reader.close();
//output.close();
}

catch(Exception exc) {
       System.out.println("ERROR");
   }
}
else if (e.getSource()==fileSave)
{ 
  int result=chooser.showSaveDialog(null);
   String s=chooser.getSelectedFile().getPath();
JOptionPane.showMessageDialog(null, "Choose:" + s,"Results",JOptionPane.INFORMATION_MESSAGE);

try{
       file=new File(s);
       output=new FileWriter(file);
       String tar=ta.getText();
       output.write(tar);
       output.close();
}
catch(Exception exc) {
       System.out.println("ERROR");
       String cmd=e.getActionCommand();
tf2.setText(cmd);
           }
       }
   }
}
class ButtonHandler implements ActionListener {
@Override
public void actionPerformed(ActionEvent evt) {
   if (evt.getSource() == b1) {
       sb=new StringBuffer(tf2.getText()).reverse();
       String str=sb.toString();
       System.out.println(str +" "+tf2.getText()) ;
   if(str.equals(tf2.getText())){
       ta.setText(str);
JOptionPane.showMessageDialog(null, "Η λέξη είναι καρκινική!!","Results",JOptionPane.INFORMATION_MESSAGE);
}
else
JOptionPane.showMessageDialog(null, "Η λέξη δεν είναι καρκινική!!","Results",JOptionPane.INFORMATION_MESSAGE);
           }
       }
   }
}

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Πρόβλημα σε πρόγραμμα JAVA!

Προτεινόμενες αναρτήσεις

LeoPao13

pantpesl2

LeoPao13

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