如何在 JPanel 中查看 JLabel 数组

Question

This is my click action:

  succ.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent arg0) {
                int x=0;
                int i;
               labelpanel.revalidate();
               labelpanel.repaint();
            for (i=status; i<status+5; i++){

                RidimIcon locand = new RidimIcon();
                labelapp.get(i).setBounds(74+x, 1, 80, 90);

                labelapp.get(i).setIcon(locand.newicona(pathicon[i], labelapp.get(i)));
                labelpanel.add(labelapp.get(i));

                    x=x+120;
               }
                status=status+5; //change status
            }

         });

"Labelpanel" is an array of JLabel:

    try {
        ResultSet rs = Datainter.eseguiQuery(query);
        while(rs.next())
        {

            pathicon[contatore] = rs.getString("locandina");

            JLabel tmplabel = new JLabel();
            labelapp.add(tmplabel);

            labelapp.get(contatore).setIcon(new ImageIcon(pathicon[contatore]));
            contatore++;

        }


    } catch (SQLException e) {
        e.printStackTrace();
    }

i want to create programm that see 5 image at click. I have an array labels with 50 images, when i click first time i see 1 - 5 labels[1-5], when i click second time i see labels[5-10], third time [10-11] etc.. Why i see only first 5 labelapp when i click on "succ"? How can i see other 5 labelapp when i click again and leave first 5 images in panel?

(with RemoveAll i cant see my last Jlabels:

             prec.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                int x=0;
                int i;
                    labelpanel.removeAll();
                        for (i=status; i<status-5; i--){

                            RidimIcon locand = new RidimIcon();
                            labelapp.get(i).setBounds(74+x, 1, 80, 90);
                            labelapp.get(i).setIcon(locand.newicona(pathicon[i], labelapp.get(i)));
                            labelpanel.add(labelapp.get(i));

                                x=x+120;

                        }
                        labelpanel.revalidate();
                        labelpanel.repaint();

                        status=status-5;
            } 
        });

Answer 1

Use removeAll() to remove all previous labels from the labelPanel . Then add new labels and call revalidate() and repaint() .

public void mouseClicked(MouseEvent arg0) {
     int x=0;
     int i;

     labelpanel.removeAll();
     for (i=status; i<status+5; i++){

         RidimIcon locand = new RidimIcon();
         labelapp.get(i).setBounds(74+x, 1, 80, 90);

         labelapp.get(i).setIcon(locand.newicona(pathicon[i], labelapp.get(i)));
         labelpanel.add(labelapp.get(i));

         x=x+120;
      }

      labelpanel.revalidate();
      labelpanel.repaint();

      status=status+5; //change status
      if(status > 17) {
          status = 17;
      }
}

And some advices;

• Use naming conventions .
• Do not use null layout. why-is-it-frowned-upon-to-use-a-null-layout-in-swing