[0M3G4]

I have tried doing ta.setText(""); but it still is failing, and placing the code before my append. I would like to clear out my JTextArea because I am building an Interpreter, and "clear" is an necessary command. I attached my projects code, basically I need a solution to clear the JTextArea ta, which system.out is being redirected to. If you have any other tips for me let me know... By the way, the "clear" command is interpreted in Interpreter > parseLine() in this block of code.

if (isCommand(token))
{
	//do command logic
	if (token.equals("clear")); //Execute logic to clear ta...
	System.out.println("this token ("+token+") is a command");
	return;
}

Just so you know, I am writing this purely for my own education, so it isn't schoolwork...

Attached File(s)

•  Hyperion.zip (1.99K)
  Number of downloads: 63

[pbl]

Whay a static JTextArea ? Not a very good practice

Simply pass the JTextArea as a parameter to the constructor of your other class so it will be able to access it

P.S.
post you code do to attach it

[0M3G4]

pbl, on 26 March 2012 - 05:00 PM, said:

Whay a static JTextArea ? Not a very good practice

Simply pass the JTextArea as a parameter to the constructor of your other class so it will be able to access it

P.S.
post you code do to attach it

Static because it is in my main class...
Would it be better if I put it in Interpreter? I am self-taught and still learning so I really don't know good practices v.s. bad practices...

Also what did you mean by "post you code do to attach it?"

[pbl]

Dont attach .zip files. Post your code using

Your main class our your main() method

The main() method, that hou haven't posted so it is just a guess, is just to start an application
shouldn't have more than few lines

class Main extend JFrame {
   
     private JTextField ta;    // not static
     Main() {
       .. the JFrame code here
     }

     public static void main(String[] args) {
        Main m = new Main();
        OtherClass oc = new OtherClass(m.ta);  // pass JTextField to other class
     }

[0M3G4]

OK, I have tried that and it doesn't work...

[pbl]

As clear as
"Mechanic, my car does not start. I changed a part, but it is still not starting"

[0M3G4]

pbl, on 26 March 2012 - 09:17 PM, said:

As clear as
"Mechanic, my car does not start. I changed a part, but it is still not starting"

I apologize for lack of clarity... I cannot get my JTextArea to clear...
This is currently my code to try and attempt to, but it still fails, the JTextArea still has text in it.

	public void clear() {
	try {
	  Document doc = textArea.getDocument();
	  doc.remove(0, doc.getLength());
	  textPane.setText(""); 
	} catch(Exception exc) {
	  System.out.println("Thar be an error on the horizon...");
      return;
	}
	}

Pardon my mistake, the above could should be:

	public void clear() {
	try {
	  Document doc = textArea.getDocument();
	  doc.remove(0, doc.getLength());
	  textArea.setText(""); 
	} catch(Exception exc) {
	  System.out.println("Thar be an error on the horizon...");
      return;
	}
	}

I am not sure how to edit these posts...

[pbl]

You are complicating your life for nothing

public void clear() {
  textArea.setText("");
}

will do it. You don't really need a method() for that type of thing

[0M3G4]

pbl, on 26 March 2012 - 10:16 PM, said:

You are complicating your life for nothing

public void clear() {
  textArea.setText("");
}

will do it. You don't really need a method() for that type of thing

I cannot get that to work... I put it just like that into my code and it fails, the text area STILL has text in it from before. I think it maybe because I am using my JTextArea as an output for System.out... I am so confused. I really would like to get this to work because the reason I switched over to this is because I needed the screen to be "clearable." OK, here is my "mainWindow" method.

Spoiler

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.text.*;

public class mainWindow extends JPanel {
	
private JFrame frame;
    public JTextPane textPane;
    private PipedOutputStream pipeOut;
    private PipedInputStream pipeIn;

    public mainWindow() {
        super(new BorderLayout());
		frame = new JFrame("Hyperion Interpreter");
        textPane = new JTextPane();
		textPane.setEditable(false);

		frame.add( new JLabel(" Output" ), BorderLayout.NORTH );
		frame.add( new JScrollPane( textPane ) );

		frame.setPreferredSize(new Dimension(300, 300));
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.pack();
		frame.setVisible( true );
		
        redirectSystemStreams();

        textPane.setBackground(Color.LIGHT_GRAY);
        //textPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    }

    private void updateTextPane(final String text) {
    SwingUtilities.invokeLater(new Runnable() {  
    public void run() {
	  append(text);
    }  
    });
    }
	
	public void clear() {
	try {
	  Document doc = textPane.getDocument();
	  doc.remove(0, doc.getLength());
	  textPane.setText(""); 
	} catch(Exception exc) {
	  System.out.println("Thar be an error on the horrizon...");
      return;
	}
	}
	
	private void append(String s) {
	try {
	  Document doc = textPane.getDocument();
      doc.insertString(doc.getLength(), s, null);
	} catch(Exception exc) {
      return;
	}
	}

    private void redirectSystemStreams() {
      OutputStream out = new OutputStream() {
        @Override
        public void write(final int B)/> throws IOException {
          updateTextPane(String.valueOf((char) B)/>);
        }

        @Override
        public void write(byte[] b, int off, int len) throws IOException {
          updateTextPane(new String(b, off, len));
        }

        @Override
        public void write(byte[] B)/> throws IOException {
          write(b, 0, b.length);
        }
      };

      System.setOut(new PrintStream(out, true));
      System.setErr(new PrintStream(out, true));
    }

}

Now here is my main:

Spoiler

import java.awt.event.*;
import java.io.*;

public class mainClass
{

public static void main(String args[]) throws InterruptedException
{
mainWindow mw = new mainWindow();
System.out.println("Hyperion Interpreter");
mw.textPane.setText("");
mw.clear();
return;
}

}

Now when I run this code, it still has "Hyperion Interpreter" in the TextPane/TextArea. I am not sure why but I cannot get it to work...

[farrell2k]

Did you never watch the movie GhostBusters??? You're not supposed to cross the streams!

Document doc = textPane.getDocument();
	  doc.remove(0, doc.getLength());
	  textPane.setText(""); 

This is redundant, as setText() calls doc.remove().

I don't fully understand why, but you redirecting System.out to that JTextpane interferes with its setText(). Why do that anyway?

[0M3G4]

farrell2k, on 27 March 2012 - 07:32 AM, said:

Did you never watch the movie GhostBusters??? You're not supposed to cross the streams!

Document doc = textPane.getDocument();
	  doc.remove(0, doc.getLength());
	  textPane.setText(""); 

This is redundant, as setText() calls doc.remove().

I didn't realize that, sorry. I was just trying both ways to see what would happen.

farrell2k, on 27 March 2012 - 07:32 AM, said:

I don't fully understand why, but you redirecting System.out to that JTextpane interferes with its setText(). Why do that anyway?

I am building a GUI frontend for a primarily console application, and I am too lazy to change all of the occurrences of System.out in it. I don't understand why either...