将Scrollbar添加到Combobox Java

Question

我有这个代码运行得很好但是我在组合框的弹出框中添加滚动条有一点问题。 1. Doese有谁知道问题出在哪里？ 2.是否也可以在组合框中添加过滤器？

JComboBox<?> comboBox;
ComboBoxModel<?> model;
JTextComponent editor;


boolean selecting=false;
boolean hidePopupOnFocusLoss;
boolean hitBackspace=false;
boolean hitBackspaceOnSelection;

KeyListener editorKeyListener;
FocusListener editorFocusListener;

public AutoCompletion(final JComboBox<?> comboBox) {
    this.comboBox = comboBox;
    model = comboBox.getModel();
    comboBox.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            if (!selecting) highlightCompletedText(0);
        }
    });
    comboBox.addPropertyChangeListener(new PropertyChangeListener() {
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getPropertyName().equals("editor")) configureEditor((ComboBoxEditor) e.getNewValue());
            if (e.getPropertyName().equals("model")) model = (ComboBoxModel<?>) e.getNewValue();
        }
    });
    editorKeyListener = new KeyAdapter() {
        public void keyPressed(KeyEvent e) {
            if (comboBox.isDisplayable()) comboBox.setPopupVisible(true);
            hitBackspace=false;
            switch (e.getKeyCode()) {

                case KeyEvent.VK_BACK_SPACE : hitBackspace=true;
                hitBackspaceOnSelection=editor.getSelectionStart()!=editor.getSelectionEnd();
                break;
                // ignore delete key
                case KeyEvent.VK_DELETE : e.consume();
                comboBox.getToolkit().beep();
                break;
            }
        }
    };

    hidePopupOnFocusLoss=System.getProperty("java.version").startsWith("1.5");

    editorFocusListener = new FocusAdapter() {
        public void focusGained(FocusEvent e) {
            highlightCompletedText(0);
        }
        public void focusLost(FocusEvent e) {

            if (hidePopupOnFocusLoss) comboBox.setPopupVisible(false);
        }
    };
    configureEditor(comboBox.getEditor());

    Object selected = comboBox.getSelectedItem();
    if (selected!=null) setText(selected.toString());
    highlightCompletedText(0);
}

public static void enable(JComboBox<?> comboBox) {

    comboBox.setEditable(true);

    new AutoCompletion(comboBox);
}

void configureEditor(ComboBoxEditor newEditor) {
    if (editor != null) {
        editor.removeKeyListener(editorKeyListener);
        editor.removeFocusListener(editorFocusListener);
    }

    if (newEditor != null) {
        editor = (JTextComponent) newEditor.getEditorComponent();
        editor.addKeyListener(editorKeyListener);
        editor.addFocusListener(editorFocusListener);
        editor.setDocument(this);
    }
}

public void remove(int offs, int len) throws BadLocationException {

    if (selecting) return;
    if (hitBackspace) {

        if (offs>0) {
            if (hitBackspaceOnSelection) offs--;
        } else {

            comboBox.getToolkit().beep(); 
        }
        highlightCompletedText(offs);
    } else {
        super.remove(offs, len);
    }
}

public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {

    if (selecting) return;

    super.insertString(offs, str, a);

    Object item = lookupItem(getText(0, getLength()));
    if (item != null) {
        setSelectedItem(item);
    } else {

        item = comboBox.getSelectedItem();

        offs = offs-str.length();

        comboBox.getToolkit().beep(); 
    }
    setText(item.toString());

    highlightCompletedText(offs+str.length());
}

private void setText(String text) {
    try {

        super.remove(0, getLength());
        super.insertString(0, text, null);
    } catch (BadLocationException e) {
        throw new RuntimeException(e.toString());
    }
}

private void highlightCompletedText(int start) {
    editor.setCaretPosition(getLength());
    editor.moveCaretPosition(start);
}

private void setSelectedItem(Object item) {
    selecting = true;
    model.setSelectedItem(item);
    selecting = false;
}

private Object lookupItem(String pattern) {
    Object selectedItem = model.getSelectedItem();

    if (selectedItem != null && startsWithIgnoreCase(selectedItem.toString(), pattern)) {
        return selectedItem;
    } else {

        for (int i=0, n=model.getSize(); i < n; i++) {
            Object currentItem = model.getElementAt(i);

            if (currentItem != null && startsWithIgnoreCase(currentItem.toString(), pattern)) {
                return currentItem;
            }
        }
    }

    return null;
}


private boolean startsWithIgnoreCase(String str1, String str2) {
    return str1.toUpperCase().startsWith(str2.toUpperCase());
}

这是滚动条的代码：

public void adjustScrollBar(JComboBox<?> comboBox) {
    this.comboBox = comboBox;
    if (comboBox.getItemCount() == 0) return;
    Object comp = comboBox.getUI().getAccessibleChild(comboBox, 0);
    if (!(comp instanceof JPopupMenu)) {
        return;
    }
    JPopupMenu popup = (JPopupMenu) comp;
    JScrollPane scrollPane = (JScrollPane) popup.getComponent(0);
    scrollPane.setHorizontalScrollBar(new JScrollBar(JScrollBar.HORIZONTAL));
    scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
}

Answer 1

好像你正试图在弹出窗口中添加一个水平滚动条。如果是，请查看Combo Box Popup以获得一个解决方案。