這是我第一次創建 Gui，我對如何創建交互感到困惑。我正在嘗試在組合框為單個時實現單一選擇模式，而在組合框被放置在多個時實現多個。我把它們放在多行注釋上。有任何想法嗎？//交互//選擇“單個”時，JLIST會更改，因此只能選擇一個項目。//選擇“多個”時，JLIST會更改，因此可以選擇多個項目//當一個國家或多個國家被選中時，JLabel 會改變以反映新的選擇public class GuiTest {public static String[] Countries = {"Africa", "Haiti", "USA", "Poland", "Russia", "Canada", "Mexico", "Cuba"};public static String[] Selection = {"Single", "Multiple"};JPanel p = new JPanel();JButton b = new JButton("Testing");JComboBox jc = new JComboBox(Selection);JList jl = new JList(Countries);private static void constructGUI() { JFrame.setDefaultLookAndFeelDecorated(true); JFrame frame = new JFrame(); frame.setTitle("Countries Selection"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // add a JLabel that says Welcome JLabel label = new JLabel("Selected Items:"); frame.add(label); frame.pack(); JComboBox jc = new JComboBox(Selection); frame.add(jc); frame.pack(); frame.setVisible(true); JList jl = new JList(Countries); frame.add(jl); frame.pack(); JComponent panel = new JPanel(); panel.setLayout(new FlowLayout()); panel.add(new JLabel("Choose Selection Mode:")); panel.add(jc); frame.add(panel, BorderLayout.NORTH); frame.add(jl, BorderLayout.WEST); frame.add(label, BorderLayout.SOUTH);}public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { constructGUI(); } });}}
2 回答
小唯快跑啊
TA貢獻1863條經驗 獲得超2個贊
它會是這樣的：
jc.addActionListener((evt) -> {
if ("Single".equals(jc.getSelectedItem())) {
jl.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
int[] sel = jl.getSelectedIndices();
if (sel != null && sel.length > 1) {
jl.setSelectedIndex(sel[0]);
}
} else {
jl.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
}
});
jl.addListSelectionListener((evt) -> {
StringBuilder buf = new StringBuilder();
for (Object o: jl.getSelectedValuesList()) {
if (buf.length() > 0) {
buf.append(", ");
}
buf.append(o);
}
label.setText(buf.toString());
});
jc.setSelectedItem("Single");
慕的地8271018
TA貢獻1796條經驗 獲得超4個贊
您應該開始將模式添加到 ComboBox：
comboBoxCategoria.addItem("Single",0);
comboBoxCategoria.addItem("Multiple",1);
然后在你的 ComboBox 中添加一個 ActionListener 來修改列表選擇模式
jc.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if(jc.getSelectedItem().equals("Single")){
jl.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
}else{//must equals
jl.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
}
}
});
最后在列表上添加一個 MouseListener 以檢測列表選擇的變化并更改 JLabel 以反映新的選擇
jl.addMouseListener(new MouseAdapter() {
@Override
public void mouseReleased(MouseEvent e) {
label.setText(list.getSelectedValuesList().toString());
}
});
編輯：您還應該添加一個 KeyListener 來更新標簽，因為可以通過箭頭鍵更改選擇
jl.addKeyListener(new KeyAdapter() {
@Override
public void keyReleased(KeyEvent e) {
label.setText(list.getSelectedValuesList().toString());
}
});
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