Question

我尝试在JTextField内添加JFrame。但它没有在窗口中显示。我使用以下代码将文本字段添加到框架中：

public static void main(String[] args) throws Exception {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        JFrame frame = new JFrame();
        frame.setTitle("Auto Completion Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBounds(200, 200, 500, 400);

        ArrayList<String> items = new ArrayList<String>();
        Locale[] locales = Locale.getAvailableLocales();
        for (int i = 0; i < 100; i++) {
            String item = ""+i+"item";
            items.add(item);
        }
        JTextField txtInput = new JTextField();
        setupAutoComplete(txtInput, items);
        txtInput.setColumns(30);
        frame.getContentPane().setLayout(new FlowLayout());
        frame.getContentPane().add(txtInput, BorderLayout.NORTH);
        frame.setSize(1000,700);
        frame.setVisible(true);
    }

我用于自动填充文字的方法如下：

 private static boolean isAdjusting(JComboBox cbInput) {
        if (cbInput.getClientProperty("is_adjusting") instanceof Boolean) {
            return (Boolean) cbInput.getClientProperty("is_adjusting");
        }
        return false;
    }

    private static void setAdjusting(JComboBox cbInput, boolean adjusting) {
        cbInput.putClientProperty("is_adjusting", adjusting);
    }

    public static void setupAutoComplete(final JTextField txtInput, final ArrayList<String> items) {
        final DefaultComboBoxModel model = new DefaultComboBoxModel();
        final JComboBox cbInput = new JComboBox(model) {
            public Dimension getPreferredSize() {
                return new Dimension(super.getPreferredSize().width, 0);
            }
        };
        setAdjusting(cbInput, false);
        for (String item : items) {
            model.addElement(item);
        }
        cbInput.setSelectedItem(null);
        cbInput.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (!isAdjusting(cbInput)) {
                    if (cbInput.getSelectedItem() != null) {
                        txtInput.setText(cbInput.getSelectedItem().toString());
                    }
                }
            }
        });

        txtInput.addKeyListener(new KeyAdapter() {

            @Override
            public void keyPressed(KeyEvent e) {
                setAdjusting(cbInput, true);
                if (e.getKeyCode() == KeyEvent.VK_SPACE) {
                    if (cbInput.isPopupVisible()) {
                        e.setKeyCode(KeyEvent.VK_ENTER);
                    }
                }
                if (e.getKeyCode() == KeyEvent.VK_ENTER || e.getKeyCode() == KeyEvent.VK_UP || e.getKeyCode() == KeyEvent.VK_DOWN) {
                    e.setSource(cbInput);
                    cbInput.dispatchEvent(e);
                    if (e.getKeyCode() == KeyEvent.VK_ENTER) {
                        txtInput.setText(cbInput.getSelectedItem().toString());
                        cbInput.setPopupVisible(false);
                    }
                }
                if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
                    cbInput.setPopupVisible(false);
                }
                setAdjusting(cbInput, false);
            }
        });
        txtInput.getDocument().addDocumentListener(new DocumentListener() {
            public void insertUpdate(DocumentEvent e) {
                updateList();
            }

            public void removeUpdate(DocumentEvent e) {
                updateList();
            }

            public void changedUpdate(DocumentEvent e) {
                updateList();
            }

            private void updateList() {
                setAdjusting(cbInput, true);
                model.removeAllElements();
                String input = txtInput.getText();
                if (!input.isEmpty()) {
                    for (String item : items) {
                        if (item.toLowerCase().startsWith(input.toLowerCase())) {
                            model.addElement(item);
                        }
                    }
                }
                cbInput.setPopupVisible(model.getSize() > 0);
                setAdjusting(cbInput, false);
            }
        });
        txtInput.setLayout(new BorderLayout());
        txtInput.add(cbInput, BorderLayout.SOUTH);
    }

我是java swing应用程序开发的新手。你能建议我这么做吗？

Answer 1

不是将组合框添加到JTextField，而是通过向其添加面板将其添加到框架中。

删除：

frame.getContentPane().setLayout(new FlowLayout()); frame.getContentPane().add(txtInput,BorderLayout.NORTH);

为什么要将布局设置为流动并将文本字段添加为borderlayout？

向框架添加主面板：

JPanel mainapnel = new JPanel(new BorderLayout());
frame.add(mainpanel);

将JTextField添加到面板：

mainpanel.add(txtInput, BorderLayout.NORTH);

修改

撤消设置JTextField的布局，而不是将ComboBox添加到JTextfield，将其添加到面板：

mainpanel.add(cbInput, BorderLayout.CENTER);

添加JTextField到JFrame没有在java中显示

1 个答案: