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我正在编写一个小程序来购买音乐。基本上它有 16 首歌曲，song1、song2、song3、song4 等作为复选框。用户应该能够选择他/她想要购买的歌曲，然后单击添加到购物车以显示购物车。根据在前一屏幕中所做的检查，购物车应该有标签。

例如：如果选中歌曲 1、3 和 5，购物车应显示三个标签 - 歌曲 1、3 和 5。

那么，如何在检查的基础上创建标签，而不必事先创建 16 个标签，从而弄得一团糟？我应该以某种方式使用数组吗？

这有点复杂，因为我已经在卡片布局中创建了复选框。我写了一个小程序（使用普通的旧记事本），带有单选按钮来选择一种流派。选择一个单选按钮会显示 4 首歌曲（这是我使用卡片的地方）。

   content_cat.setLayout(new BoxLayout(content_cat,                

                                BoxLayout.Y_AXIS));
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));
   category_label = new JLabel("Select the category");
   category_label.setAlignmentX(Component.CENTER_ALIGNMENT);
   content_cat.add(category_label);
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));
   pop = new JRadioButton("Pop");
   pop.setAlignmentX(Component.LEFT_ALIGNMENT);
   content_cat.add(pop);
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));
   rock = new JRadioButton("Rock");
   rock.setAlignmentX(Component.LEFT_ALIGNMENT);
   content_cat.add(rock);
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));
   jazz = new JRadioButton("Jazz");
   jazz.setAlignmentX(Component.LEFT_ALIGNMENT);
   content_cat.add(jazz);
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));
   hiphop = new JRadioButton("Hip hop");
   hiphop.setAlignmentX(Component.LEFT_ALIGNMENT);
   content_cat.add(hiphop);
   content_cat.add(Box.createRigidArea(new Dimension(0,30)));

   group = new ButtonGroup();
   group.add(pop);
   group.add(rock);
   group.add(jazz);
   group.add(hiphop);

   pop.addItemListener(this);
   rock.addItemListener(this);
   jazz.addItemListener(this);
   hiphop.addItemListener(this);


   //List Panel

   content_list = new Panel();
   gbc_content.gridx = 1;
   gbc_content.gridy = 0;
   gbc_content.weightx = 3;
   gbc_content.weighty = 1; 
   gbc_content.fill = GridBagConstraints.BOTH;
   content.add(content_list,gbc_content);

    content_list.setLayout(new GridBagLayout());

    //List Title Panel

    list_title = new Panel();
    gbc_list.gridx = 0;
    gbc_list.gridy = 0;
    gbc_list.weightx = 1;
    gbc_list.weighty = 1; 
    gbc_list.fill = GridBagConstraints.BOTH;
    content_list.add(list_title,gbc_list);
    list_label = new JLabel("List of CD's Available");
    list_title.add(list_label);

    //List Cards Panel

    list_card = new Panel();
    list_card.setLayout(new CardLayout());
    gbc_list.gridx = 0;
    gbc_list.gridy = 1;
    gbc_list.weightx = 1;
    gbc_list.weighty = 4; 
    gbc_list.fill = GridBagConstraints.BOTH;
    content_list.add(list_card,gbc_list);

    //Pop card

    card_pop = new Panel();
    card_pop.setLayout(new BoxLayout(card_pop,                     

                                               BoxLayout.Y_AXIS));
    card_pop.add(Box.createRigidArea(new Dimension(0,30)));
    pop1 = new JCheckBox("21 - Adele");
    pop1.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_pop.add(pop1);
    card_pop.add(Box.createRigidArea(new Dimension(0,30)));
    pop2 = new JCheckBox("D'elles - Celine Dion");
    pop2.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_pop.add(pop2);
    card_pop.add(Box.createRigidArea(new Dimension(0,30)));
    pop3 = new JCheckBox("Invincible - Michael Jackson");
    pop3.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_pop.add(pop3);
    card_pop.add(Box.createRigidArea(new Dimension(0,30)));
    pop4 = new JCheckBox("Speak Now - Taylor Swift");
    pop4.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_pop.add(pop4);
    card_pop.add(Box.createRigidArea(new Dimension(0,30)));

     //Rock card

    card_rock = new Panel();
    card_rock.setLayout(new BoxLayout(card_rock,                   

                                               BoxLayout.Y_AXIS));
    card_rock.add(Box.createRigidArea(new Dimension(0,30)));
    rock1 = new JCheckBox("Let It Be - Beatles");
    rock1.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_rock.add(rock1);
    card_rock.add(Box.createRigidArea(new Dimension(0,30)));
    rock2 = new JCheckBox("Viva la Vida - Coldplay");
    rock2.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_rock.add(rock2);
    card_rock.add(Box.createRigidArea(new Dimension(0,30)));
    rock3 = new JCheckBox("Meteora - Linkin Park");
    rock3.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_rock.add(rock3);
    card_rock.add(Box.createRigidArea(new Dimension(0,30)));
    rock4 = new JCheckBox("Dark Horse - Nickelback");
    rock4.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_rock.add(rock4);

    //Jazz card

    card_jazz = new Panel();
    card_jazz.setLayout(new BoxLayout(card_jazz,                   

                                               BoxLayout.Y_AXIS));
    card_jazz.add(Box.createRigidArea(new Dimension(0,30)));
    jazz1 = new JCheckBox("Come Sing With Me - Frank Sinatra");
    jazz1.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_jazz.add(jazz1);
    card_jazz.add(Box.createRigidArea(new Dimension(0,30)));
    jazz2 = new JCheckBox("Closer - Josh Groban");
    jazz2.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_jazz.add(jazz2);
    card_jazz.add(Box.createRigidArea(new Dimension(0,30)));
    jazz3 = new JCheckBox("Little Broken Hearts - Norah Jones");
    jazz3.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_jazz.add(jazz3);
    card_jazz.add(Box.createRigidArea(new Dimension(0,30)));
    jazz4 = new JCheckBox("Genius and Friends - Ray Charles");
    jazz4.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_jazz.add(jazz4);
    card_jazz.add(Box.createRigidArea(new Dimension(0,30)));

    //Hiphop card

    card_hiphop = new Panel();
    card_hiphop.setLayout(new BoxLayout(card_hiphop,               

                                               BoxLayout.Y_AXIS));
    card_hiphop.add(Box.createRigidArea(new Dimension(0,30)));
    hiphop1 = new JCheckBox("Curtis - 50 Cent");
    hiphop1.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_hiphop.add(hiphop1);
    card_hiphop.add(Box.createRigidArea(new Dimension(0,30)));
    hiphop2 = new JCheckBox("Freedom - Akon");
    hiphop2.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_hiphop.add(hiphop2);
    card_hiphop.add(Box.createRigidArea(new Dimension(0,30)));
    hiphop3 = new JCheckBox("Relapse - Eminem");
    hiphop3.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_hiphop.add(hiphop3);
    card_hiphop.add(Box.createRigidArea(new Dimension(0,30)));
    hiphop4 = new JCheckBox("Takin' Over");
    hiphop4.setAlignmentX(Component.LEFT_ALIGNMENT);
    card_hiphop.add(hiphop4);
    card_hiphop.add(Box.createRigidArea(new Dimension(0,30)));

    pop1.addItemListener(this);
    pop2.addItemListener(this);
    pop3.addItemListener(this);
    pop4.addItemListener(this);

    rock1.addItemListener(this);
    rock2.addItemListener(this);
    rock3.addItemListener(this);
    rock4.addItemListener(this);

    jazz1.addItemListener(this);
    jazz2.addItemListener(this);
    jazz3.addItemListener(this);
    jazz4.addItemListener(this);

    hiphop1.addItemListener(this);
    hiphop2.addItemListener(this);
    hiphop3.addItemListener(this);
    hiphop4.addItemListener(this);

  list_card.add(card_pop,POP);
  list_card.add(card_rock,ROCK);
  list_card.add(card_jazz, JAZZ);
  list_card.add(card_hiphop, HIPHOP);

底部有一个按钮可以“添加到购物车”。单击它时，它会打开一个带有购物车的新框架，这就是我要显示所选歌曲的地方。

这是事件处理代码

public void itemStateChanged(ItemEvent e)
{
 CardLayout cl = (CardLayout)(list_card.getLayout());
 if(e.getSource() == pop)
 cl.show(list_card, POP);
 if(e.getSource() == rock)
 cl.show(list_card,ROCK);
 if(e.getSource() == jazz)
 cl.show(list_card, JAZZ);
 if(e.getSource() == hiphop)
 cl.show(list_card, HIPHOP);
}

public void actionPerformed(ActionEvent e)
{
 if(e.getSource() == atc) //add to cart button
  {
   cart = new JFrame("Cart");
   cart.setVisible(true);
  }
}

所以基本上，使用 appletviewer 或网络浏览器打开小程序，选择每个流派下需要的歌曲，单击添加到购物车以显示购物车的框架。

抱歉复制粘贴这么多代码...

4

2 回答 2

0

像这样的东西怎么样：

创建歌曲：

ArrayList<String> songsSelection = new ArrayList();
ArrayList<Song> songs = new ArrayList();

//add all songs you want
songs.add( new Song(1, "Song 1")); 
songs.add( new Song(1, "Song 1")); 
songs.add( new Song(1, "Song 1"));

创建一个动作以识别选择，在这里您可以根据复选框状态删除或添加歌曲到选择

class SongAction implements ActionListener{
    public void actionPerformed(ActionEvent e) {
        JCheckBox temp = (JCheckBox)e.getSource();
        if (temp.isSelected())
            songsSelection.add(temp.getName());
        else
            songsSelection.remove(temp.getName());
        updateCart();
    }
}

创建复选框

for(Song s : songs){
    JCheckBox cb = new JCheckBox(s.getName());
    cb.addActionListener(new SongAction());
    frame.add( cb );
}

现在您可以在选择后更新您的购物车

public void updateCart(){
    panel.removeAll(); // clean the labels container
    for(String name : songsSelection ){
        panel.add(new JLable(name))
    }
}
于 2012-06-27T14:26:42.693 回答
0

在我看来，这里真正的问题是您是否需要使用标签？使用 JTextArea 来显示选择购买的歌曲不是同样有效且容易得多吗？

于 2012-06-27T16:13:04.363 回答