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

Code Java:

---

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

Code Java:

---

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
 
}

---

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.

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?

Try something like this:

Code java:

---

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.

Quote:

---

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.

Quote:

---

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)

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:

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");
        }

---

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

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.

Code :

---

 
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;
	}

---