Java“无法为最终变量赋值”

时间:2014-06-09 10:31:26

标签: java variables

public class Quiz {

    private static void homePage() {
        JFrame homePage = new JFrame("QUIZ");
        Container c = homePage.getContentPane();
        homePage.setVisible(true);
        homePage.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        homePage.setBounds(600,180,700,400);
        homePage.setResizable(false);
        homePage.setContentPane(c);

        JLabel benvenuto = new JLabel("Benvenuto!");
        benvenuto.setFont(new Font("Serif", Font.BOLD, 30));
        benvenuto.setBounds(265,0,180,120);
        benvenuto.setOpaque(true);

        JLabel label1 = new JLabel("Inserisci il tuo nome:");
        label1.setBounds(215,100,120,100);
        label1.setOpaque(true);

        JTextArea areaNome = new JTextArea();
        areaNome.setEditable(true);
        areaNome.setFont(new Font("Serif", Font.BOLD, 16));
        areaNome.setBounds(345,142,120,20);
        javax.swing.border.Border borderP = BorderFactory.createLineBorder(Color.BLACK);
        areaNome.setBorder(borderP);

        JLabel labelStarting = new JLabel();
        labelStarting.setBounds(230,230,280,120);
        labelStarting.setForeground(Color.RED);

        JButton startButton = new JButton("Inizia");
        startButton.setBounds(280,200,120,50);
        startButton.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e)
            {
                String gt1 = areaNome.getText();
                try {
                    Thread.sleep(500);
                } catch (InterruptedException ex) {
                    Logger.getLogger(Quiz.class.getName()).log(Level.SEVERE, null, ex);
                }
                labelStarting.setText("Preparati "+gt1+", il gioco sta per iniziare.");

                JFrame quizPage = new JFrame("QUIZ");
                quizPage.setBounds(573,150,750,450);
                quizPage.setVisible(true);
                quizPage.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                quizPage.setResizable(false);
                Container c2 = quizPage.getContentPane();
                quizPage.setContentPane(c2);

                JLabel domanda1 = new JLabel("1) Qual è la capitale d'Italia?");
                domanda1.setBounds(0,0,280,120);

                JLabel domanda2 = new JLabel("2) Quanto fa 2^8?");
                domanda2.setBounds(0,55,280,120);   

                JLabel domanda3 = new JLabel("3) Quando è stata scoperta l'America da Colombo?");
                domanda3.setBounds(0,110,380,120);

                JLabel domanda4 = new JLabel("4) Dove si trova l'Empire State Building?");
                domanda4.setBounds(0,165,280,120);

                JLabel domanda5 = new JLabel("5) Qual è il nome dell'autore della Divina Commedia?");
                domanda5.setBounds(0,220,380,120);

                JLabel labelNull2 = new JLabel();
                labelNull2.setBounds(230,230,280,120);

                JTextArea r1 = new JTextArea();
                r1.setBounds(320,50,120,20);
                javax.swing.border.Border border1 = BorderFactory.createLineBorder(Color.BLACK);
                r1.setBorder(border1);

                JTextArea r2 = new JTextArea();
                r2.setBounds(320,105,120,20);
                javax.swing.border.Border border2 = BorderFactory.createLineBorder(Color.BLACK);
                r2.setBorder(border2);

                JTextArea r3 = new JTextArea();
                r3.setBounds(320,160,120,20);
                javax.swing.border.Border border3 = BorderFactory.createLineBorder(Color.BLACK);
                r3.setBorder(border3);

                JTextArea r4 = new JTextArea();
                r4.setBounds(320,217,120,20);
                javax.swing.border.Border border4 = BorderFactory.createLineBorder(Color.BLACK);
                r4.setBorder(border4);

                JTextArea r5 = new JTextArea();
                r5.setBounds(320,270,120,20);
                javax.swing.border.Border border5 = BorderFactory.createLineBorder(Color.BLACK);
                r5.setBorder(border5);

                JButton br1 = new JButton("Conferma");
                br1.setBounds(475,49,120,25);

                JButton br2 = new JButton("Conferma");
                br2.setBounds(475,105,120,25);

                JButton br3 = new JButton("Conferma");
                br3.setBounds(475,160,120,25);

                JButton br4 = new JButton("Conferma");
                br4.setBounds(475,216,120,25);

                JButton br5 = new JButton("Conferma");
                br5.setBounds(475,270,120,25);

                JLabel lp1 = new JLabel();
                lp1.setBounds(635,45,100,30);
                lp1.setForeground(Color.GREEN);

                JLabel lp2 = new JLabel();
                lp2.setBounds(635,103,100,30);
                lp2.setForeground(Color.GREEN);

                JLabel lp3 = new JLabel();
                lp3.setBounds(635,158,100,30);
                lp3.setForeground(Color.GREEN);

                JLabel lp4 = new JLabel();
                lp4.setBounds(635,213,100,30);
                lp4.setForeground(Color.GREEN);

                JLabel lp5 = new JLabel();
                lp5.setBounds(635,269,100,30);
                lp5.setForeground(Color.GREEN);

                JLabel lp11 = new JLabel();
                lp11.setBounds(635,45,100,30);
                lp11.setForeground(Color.RED);

                JLabel lp22 = new JLabel();
                lp22.setBounds(635,103,100,30);
                lp22.setForeground(Color.RED);

                JLabel lp33 = new JLabel();
                lp33.setBounds(635,158,100,30);
                lp33.setForeground(Color.RED);

                JLabel lp44 = new JLabel();
                lp44.setBounds(635,213,100,30);
                lp44.setForeground(Color.RED);

                JLabel lp55 = new JLabel();
                lp55.setBounds(635,269,100,30);
                lp55.setForeground(Color.RED);

                int number = 0;

                br1.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e)
                    {
                        String sr1 = r1.getText();
                        if(sr1.equals("Roma")||sr1.equals("roma")) {
                            lp1.setText("ESATTO");
                            number += 1;
                        }else {
                            lp11.setText("ERRATO");
                        }
                    }
                });

                br2.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e)
                    {
                        String sr2 = r2.getText();
                        if(sr2.equals("256")) {
                            lp2.setText("ESATTO");
                        }else {
                            lp22.setText("ESATTO");
                        }
                    }
                });

                br3.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e)
                    {
                        String sr3 = r3.getText();
                        if(sr3.equals("1492")) {
                            lp3.setText("ESATTO");
                        }else {
                            lp33.setText("ERRATO");
                        }
                    }
                });

                br4.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e)
                    {
                        String sr4 = r4.getText();
                        if(sr4.equals("New York")||sr4.equals("new york")) {
                            lp4.setText("ESATTO");
                        }else {
                            lp44.setText("ERRATO");
                        }
                    }
                });

                br5.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e)
                    {
                        String sr5 = r5.getText();
                        if(sr5.equals("Dante")||sr5.equals("dante")) {
                            lp5.setText("ESATTO");
                        }else {
                            lp55.setText("ERRATO");
                        }
                    }
                });

                JLabel risultato = new JLabel("Il tuo punteggio finale è: "+number+"/5");
                risultato.setBounds(10,320,300,60);


                c2.add(domanda1);
                c2.add(domanda2);
                c2.add(domanda3);
                c2.add(domanda4);
                c2.add(domanda5);
                c2.add(r1);
                c2.add(r2);
                c2.add(r3);
                c2.add(r4);
                c2.add(r5);
                c2.add(br1);
                c2.add(br2);
                c2.add(br3);
                c2.add(br4);
                c2.add(br5);
                c2.add(lp1);
                c2.add(lp2);
                c2.add(lp3);
                c2.add(lp4);
                c2.add(lp5);
                c2.add(lp11);
                c2.add(lp22);
                c2.add(lp33);
                c2.add(lp44);
                c2.add(lp55);
                c2.add(risultato);
                c2.add(labelNull2);
            }
        });



        JLabel labelNull = new JLabel();



        c.add(benvenuto);
        c.add(label1);
        c.add(areaNome);
        c.add(startButton);
        c.add(labelStarting);
        c.add(labelNull);

    }

    public static void main(String[] args) {
        homePage();
    }
}

在按钮br1的动作侦听器之前有变量(int number = 0;),如果9行向下,它会增加但它会给我一个错误:从内部类引用的局部变量必须是最终的或有效的final ...如果我让数字到最后(最终的int数= 0;)增加给我另一个错误:不能给最终变量号赋值...其中' s错误??

2 个答案:

答案 0 :(得分:0)

number方法之外定义您的homepage变量,这样可以正常工作而不是最终

修改 首先从int number = 0;方法中删除此homepage,然后在方法外定义数字:

public class Quiz {
   static int number = 0;

    private static void homePage() {
    //homepage body
    }
}

这应该使它编译

现在很少有评论

  1. 让你的方法非静态,我知道这只是你在玩,但静态方法和变量是编码错误的迹象。
  2. 你的号码实际上在做什么?只有你正在使用它的地方,就在这里

    JLabel risultato = new JLabel("Il tuo punteggio finale è: "+number+"/5");

    如果您的号码会更改,则此标签不会更新,为了使其正常工作,您需要更新标签内的文字

答案 1 :(得分:-1)

我学到的一个技巧是制作一个包含1个元素的数组。这样,你可以这样做:

final int[] number = { 0 };

number[0] = 4; // random number picked

现在您可以将值设置为最终变量:)