Question

Im new in Java socket and i try to develop a small game through socket, everything is ok on server but in client , i got trouble when i create a list of JLabel to show a letter “_” for each letter of word

Ok i show my code you will see what trouble i got.

my Snippett code like this:

List<JLabel>labels;

 private void getWordLabels(String word){
        char[] chars  = word.toCharArray();
        System.out.println(chars);
        int gapBetweenLetter = 300/chars.length;
        labels = new ArrayList<JLabel>();

        for(int i =0; i< chars.length ;i++){

           // JLabel l = new JLabel("_");
            labels.add(new JLabel());
            labels.get(i).setText("_");
            //this.add(l);
            //l.setBounds(10, 10, 10, 10);
            //l.show();
            this.removeAll();
            this.revalidate();
            this.repaint();
            labels.get(i).setBounds((i*gapBetweenLetter) + 10, 100, 50, 50);

            this.add(labels.get(i));

            labels.get(i).show();
             initComponents();

        /* labels.add(new JLabel("_"));
        this.add(labels.get(i));
        //labels[i].setText("_");
        System.out.println(labels.get(i));
        * */


    }
}
    }

but i got null pointer exception, i don’t know why?

Someone can help me or show what wrong in my code.

Thank you!

Answer 1

Can’t see anything obvious, so I’d start by refactoring to

for(int i =0; i< chars.length ;i++){
        JLabel l = new JLabel("_");
        labels.add(l);
        this.add(l);
        //labels[i].setText("_");
        System.out.println(l);
    }

which may help you to see the problem. It also avoids repeating the get(i) [probably not expensive on an ArrayList, but still]

BTW: what type is ‘this’?