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Thread: Trying to display text from file in JTextArea. Please Help.

  1. #1
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    Default Trying to display text from file in JTextArea. Please Help.

    I'm trying to display some text in a JTextArea I have set up in a simple GUI. Easy right? That's what I thought, but I'm clearly not that advanced at Java. The hook is the information I want to display in the JTextArea is in a text file (file.txt).

    Right now I have a main class and a class called TextArea that houses the GUI and two methods. In the main class I have set up a simple array with some text in it, and I'm able to get it to display in the JTextArea. Basically the code all works fine, the only thing I can't figure out and need to change is have the information in the array coming from a text file. So if anyone can help me figure this out I'd really appreciate it.

    Here's my code for the Main class

    package texttoarraylist;
     
    import java.util.*;
    import java.io.*;
     
    /**
     *
     * @author RJ
     */
    public class Main {
     
        /**
         * @param args the command line arguments
         */
        public static void main(String[] args) {
     
         String dvds [] = {"text1", "text2"};
     
            ArrayList myList = new ArrayList();
            for (int sub = 0; sub < dvds.length; sub++){
                myList.add(dvds[sub]);
            }
     
            TextArea one = new TextArea();
            one.setVisible(true);
            one.setShowText(myList);
     
        }
    }

    And here's the code for the TextArea Class

    package texttoarraylist;
     
    /**
     *
     * @author RJ
     */
    public class TextArea extends javax.swing.JFrame {
     
        /** Creates new form TextArea */
        public TextArea() {
            initComponents();
        }
     
        /** This method is called from within the constructor to
         * initialize the form.
         * WARNING: Do NOT modify this code. The content of this method is
         * always regenerated by the Form Editor.
         */
        @SuppressWarnings("unchecked")
        // <editor-fold defaultstate="collapsed" desc="Generated Code">
        private void initComponents() {
     
            jScrollPane1 = new javax.swing.JScrollPane();
            textArea = new javax.swing.JTextArea();
     
            setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
     
            textArea.setColumns(20);
            textArea.setEditable(false);
            textArea.setLineWrap(true);
            textArea.setRows(5);
            jScrollPane1.setViewportView(textArea);
     
            javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
            getContentPane().setLayout(layout);
            layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(20, 20, 20)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 272, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(108, Short.MAX_VALUE))
            );
            layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(22, 22, 22)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 257, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(21, Short.MAX_VALUE))
            );
     
            pack();
        }// </editor-fold>
     
     
         private java.util.ArrayList getShowText(){
            //go to tShow and get its text, put it into one string
            String dvd = textArea.getText();
     
            java.util.ArrayList myList = new java.util.ArrayList();
            java.util.StringTokenizer one = new java.util.StringTokenizer(dvd, "\n");
     
            while(one.hasMoreElements()){
                myList.add(one.nextToken());
            }
     
     
            return myList;
        }
     
     
     
        public void setShowText(java.util.ArrayList myList){
     
            String show = new String();
            for (int sub = 0; sub < myList.size(); sub++)
                show += myList.get(sub) + "\n";
     
            textArea.setText(show);
        }
     
        /**
        * @param args the command line arguments
        */
        public static void main(String args[]) {
            java.awt.EventQueue.invokeLater(new Runnable() {
                public void run() {
                    new TextArea().setVisible(true);
                }
            });
        }
     
        // Variables declaration - do not modify
        private javax.swing.JScrollPane jScrollPane1;
        private javax.swing.JTextArea textArea;
        // End of variables declaration
     
    }


  2. #2
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    Default Re: Trying to display text from file in JTextArea. Please Help.

    See the following link for all the nitty gritty on File IO: Lesson: Basic I/O (The Java™ Tutorials > Essential Classes)
    For text files, see Reading, Writing, and Creating Files (The Java™ Tutorials > Essential Classes > Basic I/O) , which gives some basic code for how to read a file line by line.

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    Default Re: Trying to display text from file in JTextArea. Please Help.

    Isn't there some quick solution to this though? Like, I think I'm only missing a little piece of the code. Can't you do some version of:

    String dvds [] = new BufferedReader(fileName("file.txt"));

    This is obviously not working, but isn't there something like that that can just take a text file and throw it into an ArrayList, or an Array and then the Array into an ArrayList?

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    Cool Re: Trying to display text from file in JTextArea. Please Help.

    Try something like this:



    JTextArea area = new JTextArea(30,30);
     
    String str = "";
    Scanner reader = new Scanner("File.txt");
     
    while (reader.hasNext())
    {
    str = str + reader.nextLine();
    }
    area.setText(str);

    I'm not sure what the array does.

    Are you storing each line as an index in the array?

    Also, ArrayList is generic.

    ArrayList<String> list = new ArrayList<String>();

    list.add("some words");

    // the above is how to add to an ArrayList.

    You could add it using the loop I showed above.

    As for your question in your last post, the answer is a no.

    A String array cannot be initialized to a BufferReader object, which is what that's doing.

    In fact, you can't even initialize just a plain old String to that either.

    You need to use a Scanner in any event.

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    Default Re: Trying to display text from file in JTextArea. Please Help.

    You need to use a Scanner in any event.
    No you don't need to use Scanner. In fact, a BufferedReader is just that: buffered (aka faster). And if you are doing string addition, recommend you use a StringBuffer or StringBuilder.

    String dvds [] = new BufferedReader(fileName("file.txt"));
    You cannot assign variables like that...you must loop through the file and read it. That link I provided above shows some simple code for how to do this, as does javapenguin's code above (although I recommend against using String addition and recommend using a BufferedReader)

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    Default Re: Trying to display text from file in JTextArea. Please Help.

    I've pretty much figured out all of the major issues I was having trouble with, thanks to the help from the people in these forums(thanks!). The info from my text file is displaying in the JTextArea but for some reason I can only get the last line of the file to display. There are 10 lines in the text file that I'm trying to display.

    Here's my updated code:

     
    public TextArea() {
            initComponents();
     
     
            try {
                FileReader one = new FileReader ("info.txt");
                BufferedReader buf = new BufferedReader(one);
     
                String line = "";
                StringTokenizer st = null;
                int lineNumber = 0, tokenNumber = 0;
                //textArea.setText(line);
     
                while ((line = buf.readLine()) != null) {
                    lineNumber++;
     
                    //break comma separated line using ","
                    st = new StringTokenizer(line, ",");
     
                    while (st.hasMoreTokens()) {
                        //display csv values
                        tokenNumber++;
                        line = ("Title: " + st.nextToken()
                                + "\n" + "Make:" + st.nextToken()
                                + "\n" + "Model:" + st.nextToken()
                                + "\n" + "Year:" + st.nextToken()
                                + "\n" + "Price:" + st.nextToken()
                                + "\n" + "Notes:" + st.nextToken()
                                + "\n" + "Details:" + st.nextToken()
                                + "\n");
     
                        textArea.setText(line);
                    }
     
                    //reset token number
                    tokenNumber = 0;
                    //textArea.setText(line);
                }
     
            } catch (FileNotFoundException e) {
                JOptionPane.showMessageDialog(this, "File not found");
            } catch (IOException e){
                JOptionPane.showMessageDialog(this, "Data not read");
            }

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    Default Re: Trying to display text from file in JTextArea. Please Help.

    The JTextArea.setText(..) method replaces the text. To append text to it, use the JTextArea.append(..) method.

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    Default Re: Trying to display text from file in JTextArea. Please Help.

    Hi,

    i have the same problem. I trying to display a text in JTextArea.
    @rjdelight : Did you find a solution?
    @All: or Here is my code. If somebody has an idea.
     
    private String string;
    	public MyDocument() {
    		try {
    			int offset = 0;
    			int x = 0;
    			for (int i = 0; i < 1024; i++) {
    				string = UUID.randomUUID().toString() + "\n";
    				if ((string != null) && (x < 10)) {
    					x++;
    				}
    				insertString(offset, string, null);
    				offset += string.length();
    			}
    		} catch (BadLocationException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
     
    	@Override
    	public String getText(int offset, int length) throws BadLocationException {
    		System.out.println(String.format("getText: Offset %d / Length: %d",
    				offset, length));
     
    		return super.getText(offset, length);
    	}
     
    	@Override
    	public void getText(int offset, int length, Segment seg)
    			throws BadLocationException {
    		System.out.println(String.format(
    				"getTextWithSegment: Offset %d / Length: %d", offset, length));
    		super.getText(offset, length, seg);
    	}
     
    	@Override
    	public int getLength() {
    		int length = super.getLength();
    		System.out.println("getLength: " + length);
    		return length;
    	}

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