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Thread: Why doesn't JTextArea execute in this piece of code?

  1. #1
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    Default Why doesn't JTextArea execute in this piece of code?

    Hi I have the following code:
    JFrame jframe = new JFrame ();
        .........
        JTextArea ta = new JTextArea(20,40);  
       .........
          try {
            FileReader fr = new FileReader ("indice.txt");
            BufferedReader br = new BufferedReader (fr);	
            System.out.println ("O arquivo-indice existe!");
            ta.setText ("TESTE1");
            ta.setText ("O arquivo-indice existe!");
            ta.setText ("TESTE2");
            if (fm.checkFileList ())  
              //System.out.println ("Arquivo indice nao foi modificado. Nada a fazer");  
    	  ta.setText ("Arquivo indice nao foi modificado. Nada a fazer");
            else {
              //System.out.println ("Arquivo índice foi modificado. Atualizando arquivo índice de reserva: "); 
              ta.setText ("Arquivo índice foi modificado. Atualizando arquivo índice de reserva: "); 
              fm.printFileList();
            }

    As can be seen there is a
     ta.setText ("O arquivo-indice existe!");
    and two lines above there is
    System.out.println ("O arquivo-indice existe!")
    . Or, in another words, with the same content.
    This is because I am using the JTextArea to substitute the System.out.println
    The problem it is.......that JTextArea ain't showing anything! More specifically it doesn't show anything only in this piece of code. I added
    ta.setText ("TESTE1");
    and
    ta.setText ("TESTE2");
    to test it and they both also doesn't work. The
    System.out.println ("O arquivo-indice existe!");
    that it is previous to them work as a charm. And so does
    ta.setText
    that exists inside of the if-else clauses.........so what is going on?


  2. #2
    Super Moderator jps's Avatar
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    Default Re: Why doesn't JTextArea execute in this piece of code?

    I don't see where the text area is ever added to the frame.
    I don't see where the frame is ever set visible.
    The words "doesn't work" does not offer much insight to the problem. Try to explain exactly what does happen, and exactly what you want to happen. Also try to explain where in the code things seem to go unexpected.

    Does the frame even show? It is okay to post code snippets, (even encouraged to do so), but you should include enough code to get the complete picture. (In this case the code that adds ta to jframe and where jframe is setVisible)

  3. #3
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    Default Re: Why doesn't JTextArea execute in this piece of code?

    Quote Originally Posted by jps View Post
    I don't see where the text area is ever added to the frame.
    I don't see where the frame is ever set visible.
    It is okay to post code snippets, (even encouraged to do so), but you should include enough code to get the complete picture. (In this case the code that adds ta to jframe and where jframe is setVisible)
    More of the code:

        JFrame jframe = new JFrame ();
        jframe.setVisible (true);
        jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
        JTextArea ta = new JTextArea(20,40);  
        jframe.getContentPane().add(new JScrollPane(ta));  
        jframe.pack();
        if (args[2].equals ("bi")) {
          try {
            FileReader fr = new FileReader ("indice.txt");
            BufferedReader br = new BufferedReader (fr);	
            System.out.println ("O arquivo-indice existe!");
            ta.setText ("TESTE1");
            ta.setText ("O arquivo-indice existe!");
            ta.setText ("TESTE2");
            if (fm.checkFileList ())  
              //System.out.println ("Arquivo indice nao foi modificado. Nada a fazer");  
    	  ta.setText ("Arquivo indice nao foi modificado. Nada a fazer");
            else {
              //System.out.println ("Arquivo índice foi modificado. Atualizando arquivo índice de reserva: "); 
              ta.setText ("Arquivo índice foi modificado. Atualizando arquivo índice de reserva: "); 
              fm.printFileList();
            }

    The words "doesn't work" does not offer much insight to the problem. Try to explain exactly what does happen, and exactly what you want to happen. Also try to explain where in the code things seem to go unexpected.

    Does the frame even show?
    This code
    ta.setText ("TESTE1");
            ta.setText ("O arquivo-indice existe!");
            ta.setText ("TESTE2");

    doesn't show up in the window. The rest work as intended. Simple like that


    UPDATED: I figured out what it is the problem. It is showing only the last line. More precisely, it overwrites the last line when it receives a new one. So in my example it is gonna show what it is inside the if/else clause. But what I need to do so the frame keep the old lines?

    UPDATED2: I find out that the problem was that I was using SetText. Instead I should be using the append method

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