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Thread: Somethink with ArrayList

  1. #1
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    Default Somethink with ArrayList

    Hello guys. I started learning Java with book for beginners ("Head First Java"). And now I have a problem with code from one task. My compilation program show me that problem with ArrayList (later QuizCard and cardList everywhere). I don't know how fix it. Help me. Thanks.

     
     
    import javax.swing.*;
    import java.util.*;
    import java.awt.*;
    import java.io.*;
    import java.awt.event.*;
     
    public class QuizCardBuilder {
     
    	private JTextArea question;
    	private JTextArea answer;
    	private ArrayList<QuizCard> cardList;
    	private JFrame frame;
     
      public static void main(String[] args) {
    	  QuizCardBuilder builder = new QuizCardBuilder();
    	  builder.go();
      }
     
      public void go() {
     
    	  frame = new JFrame("Quiz Card Builder");
    	  JPanel mainPanel = new JPanel();
    	  Font bigFont = new Font("sanserif", Font.BOLD, 24);
    	  question = new JTextArea(6,20);
    	  question.setLineWrap(true);
    	  question.setWrapStyleWord(true);
    	  question.setFont(bigFont);
     
    	  JScrollPane qScroller = new JScrollPane(question);
    	  qScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    	  qScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
     
    	  answer = new JTextArea(6,20);
    	  answer.setLineWrap(true);
    	  answer.setWrapStyleWord(true);
    	  answer.setFont(bigFont);
     
    	  JScrollPane aScroller = new JScrollPane(answer);
    	  aScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    	  aScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
     
    	  JButton nextButton = new JButton("Next Card");
     
    	  cardList = new ArrayList<QuizCard>();
     
    	  JLabel qLabel = new JLabel("Question:");
    	  JLabel aLabel = new JLabel("Answer:");
     
    	  mainPanel.add(qLabel);
    	  mainPanel.add(qScroller);
    	  mainPanel.add(aLabel);
    	  mainPanel.add(aScroller);
    	  mainPanel.add(nextButton);
    	  nextButton.addActionListener(new NextCardListener());
    	  JMenuBar menuBar = new JMenuBar();
    	  JMenu fileMenu = new JMenu("File");
    	  JMenuItem newMenuItem = new JMenuItem("New");
    	  JMenuItem saveMenuItem = new JMenuItem("Save");
    	  newMenuItem.addActionListener(new NewMenuListener());
     
    	  saveMenuItem.addActionListener(new SaveMenuListener());
    	  fileMenu.add(newMenuItem);
    	  fileMenu.add(saveMenuItem);
    	  menuBar.add(fileMenu);
     
          frame.setJMenuBar(menuBar);
          frame.getContentPane().add(BorderLayout.CENTER, mainPanel);
    	  frame.setSize(500,600);
    	  frame.setVisible(true);
      }
     
      public class NextCardListener implements ActionListener {
    	public void actionPerformed(ActionEvent ev) {
    		QuizCard card = new QuizCard(question.getText(), answer.getText());
    		cardList.add(card);
    		clearCard();
     
    	}
      }
     
      public class SaveMenuListener implements ActionListener {
    	public void actionPerformed(ActionEvent ev) {
    		QuizCard card = new QuizCard(question.getText(), answer.getText());
    		cardList.add(card);
     
    		JFileChooser fileSave = new JFileChooser();
    		fileSave.showSaveDialog(frame);
    		saveFile(fileSave.getSelectedFile());
     
    	}
      }
     
      public class NewMenuListener implements ActionListener {
    		public void actionPerformed(ActionEvent ev) {
    			cardList.clear();
    			clearCard();
     
    		}
    	  }
     
      private void clearCard() {
    	  question.setText(" ");
    	  answer.setText(" ");
    	  question.requestFocus();
      }
     
      private void saveFile(File file) {
    	  try {
    		  BufferedWriter writer = new BufferedWriter(new FileWriter(file));
     
    		  for(QuizCard card:cardList) {
    			  writer.write(card.getQuestion()+"/");
    			  writer.write(card.getAnswer()+"\n");
    		  }
    		  writer.close();
    	  } catch(IOException ex) {
    		  System.out.println("couldn't write the cardList out");
    		  ex.printStackTrace();
    	  }
      }
     
     
     
    }


  2. #2
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    Default Re: Somethink with ArrayList

    Welcome to the forum! Thanks for taking the time to learn how to post code correctly. If you haven't already, please read this topic to learn other useful info for new members.

    If you're asking for help with an error, please post the entire text of the error message.

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