JtextArea zeigt nichts an!

[ioannis]

Hallo,

Ich habe folgenden Code und mir ist nicht ganz klar warum die JTextarea keinen Ausdruck "Das darf doch nicht wahr sein ausgibt!" Es geschiet nämlich garnichts. Das Frame wird komplet mit Grauer Farbe geladen, aber keine Text Area. Wenn ich das textInput =new JTextArea() auskommentiere dann läuft der weitere Teil des PRogramms wie gewünscht ab, ohne natürlich die JTextArea anzuzeigen..:-( Kann mir jemand weiterhelfen?

import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
    
   class Main {
    
    /** Creates a new instance of Main */
    public Main() {
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
     
      new TextCounterApplet().init();
    }
    
}
    
    public class TextCounterApplet extends JFrame 
                                      implements ActionListener {
    
         
  
       JTextArea textInput;     // For the user's input text.
       
       JLabel lineCountLabel;   // For displaying the number of lines.
       JLabel wordCountLabel;   // For displaying the number of words.
       JLabel charCountLabel;   // For displaying the number of chars.
    
    
       public void init() {
            JFrame f = new JFrame("United Colors"); 
     f.setVisible(true);
          f.setSize(500,500);
          f.setBackground(Color.RED);
         f.getContentPane().setBackground(Color.darkGray);
           
          textInput = new JTextArea("Das darf doch nicht war sein");
          // Setze die Schriftart
            Font schrift = new Font("SansSerif",Font.BOLD+Font.ITALIC,16);
            textInput.setFont(schrift);
      //textInput.setBackground(Color.white);
            
          
          /* Create the text input area and make sure it has a
             white background. */
          
          
         
          /* Create a panel to hold the button and three display
             labels.  These will be laid out in a GridLayout with
             4 rows and 1 column. */
          
          JPanel south = new JPanel();
          south.setBackground(Color.darkGray);
          south.setLayout( new GridLayout(4,1,2,2) );
          
          /* Create the button, set the applet to listen for
             clicks on the button, and add it to the panel. */
          
          JButton countButton = new JButton("Process the Text");
          countButton.addActionListener(this);
          south.add(countButton);
          
          /* Create each of the labels, set their colors, and
             add them to the panel. */
          
          lineCountLabel = new JLabel("  Number of lines:");
          lineCountLabel.setBackground(Color.white);
          lineCountLabel.setForeground(Color.blue);
          lineCountLabel.setOpaque(true);
          south.add(lineCountLabel);
          
          wordCountLabel = new JLabel("  Number of words:");
          wordCountLabel.setBackground(Color.white);
          wordCountLabel.setForeground(Color.blue);
          wordCountLabel.setOpaque(true);
          south.add(wordCountLabel);
          
          charCountLabel = new JLabel("  Number of chars:");
          charCountLabel.setBackground(Color.white);
          charCountLabel.setForeground(Color.blue);
          charCountLabel.setOpaque(true);
          south.add(charCountLabel);
          
          /* Use a BorderLayout on the applet.  Although a BorderLayout
             is the default, I want one with a vertical gap of two
             pixels, to let the dark gray background color show through. */
             
          //getContentPane().setLayout( new BorderLayout(2,2) );
             
          /* The text area is put into a JScrollPane to provide
             scroll bars for the TextArea, and the scroll pane is put in
             the Center position.  The panel that holds the button and
             labels is in the South position.  Note that the text area
             will be sized to fill the space that is left after the
             panel is assigned its preferred height. */
          
          textInput.setLineWrap(true);
    textInput.setWrapStyleWord(true);
         JScrollPane scroller = new JScrollPane(textInput);
         getContentPane().add(scroller, BorderLayout.CENTER);
          f.getContentPane().add(south, BorderLayout.SOUTH);
        
       } // end init();
       
       
       public  Insets getInsets() {
             // Leave a 2-pixel border around the edges of the applet.
          return new Insets(2,2,2,2);
       }
       
    ...
    ...
    ...
    ...

Vielen Dank

Ioannis

 

[Wildcard]

Von JFrame zu erben und dann einen JFrame zu instanzieren macht schonmal keinen Sinn.

 

[André Uhres]

class TextCounterApplet implements ActionListener {//<---------------------- kein extends
...
    public void init() {
        JFrame f = new JFrame("United Colors");
//        f.setVisible(true);//<-------------------------------------------- dies raus
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
...
        f.getContentPane().add(scroller, BorderLayout.CENTER);//<----------- f.
        f.getContentPane().add(south, BorderLayout.SOUTH);
        f.setVisible(true);//<---------------------------------------------- dies rein
    } // end init();
...
}

Der Fehler ist unter anderem, daß du den Frame zu früh sichtbar machst: f.setVisible(true);
alles was du danach noch zum Frame hinzufügst, wird nicht angezeigt,
ausser du machst zum Schluss nocht ein f.validate();
Hier ist es logischer, den setVisible einfach erst zum Schluss zu machen.

 

[ioannis]

Tatsächlich,

es funktioniert!

Vielen Dank