java - JComboBox 对于 JFrame 来说太长

Question

我对 JComboBox 和长字符串有疑问。结果是 JComboBox 对于 JFrame 来说太长，因此它不会显示整个框。这里我有一些代码显示了我的问题:

    JFrame frame = new JFrame();
    frame.setSize(500, 500);
    JPanel panel = new JPanel();
    DesignGridLayout layout = new DesignGridLayout(panel);
    Vector<ArrayList<String>> content = new Vector<ArrayList<String>>();
    ArrayList<String> list = new ArrayList<String>();
    list.add("12345");
    list.add("abcde");
    list.add("12345");
    list.add("abcde");
    list.add("12345");
    list.add("abcde");
    list.add("12345");
    list.add("abcde");
    list.add("12345");
    list.add("abcde");
    list.add("12345");
    list.add("abcde");
    content.add(list);
    ComboBoxFullMenu<ArrayList<String>> combobox = new ComboBoxFullMenu<ArrayList<String>>(content);
    combobox.setRenderer(new DefaultListCellRenderer() {

        private static final long serialVersionUID = 1L;

        @Override
        public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) 
        {
            super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            ArrayList<String> array = (ArrayList<String>) value;
            if (!array.isEmpty())
            {
                String text = "";
                for (String info : array)
                {
                    text += info + "; ";
                }
                setText(text);
            }
            return this;
        }
    });
    AutoCompleteDecorator.decorate(combobox, new ObjectToStringConverter()
    {

        @Override
        public String getPreferredStringForItem(Object object)
        {
            if (object != null)
            {
                if (object instanceof ArrayList)
                {
                    ArrayList<String> list = (ArrayList<String>) object;
                    String text = "";
                    for (String info : list)
                    {
                        text += info + "; ";
                    }
                    return text;
                }
                else
                {
                    return object.toString();
                }
            }
            return null;
        }
    });
    layout.row().grid().add(combobox);
    frame.add(panel);
    frame.setVisible(true);

这是 ComboBoxFullMenu 类:

public class ComboBoxFullMenu<E> extends JComboBox<E>
{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public ComboBoxFullMenu(Vector<E> items) 
    {
        super(items);
        addActionListener(this);
    }

    public ComboBoxFullMenu()
    {
        super();
        addActionListener(this);
    }

    public ComboBoxFullMenu (DefaultComboBoxModel<E> defaultComboBoxModel)
    {
        super(defaultComboBoxModel);
        addActionListener(this);
    }

    /**
     * Small hack to get pop up menu size bigger enough to show items even though
     * the combo box size could be smaller
     * */
    private boolean layingOut = false; 

    @Override
    public void doLayout()
    { 
        try
        { 
            layingOut = true; 
            super.doLayout(); 
        }
        finally
        { 
            layingOut = false; 
        } 
    } 

    @Override
    public Dimension getSize()
    { 
        Dimension dim = super.getSize(); 
        if ( !layingOut ) 
        {
            dim.width = Math.max(dim.width, getPreferredSize().width);
        }
        return dim; 
    }
}

我还尝试使用 DefaultListCellRenderer 和 ObjectTroStringConverter 以较短的方式显示所选项目，但我需要查看下拉菜单中的所有信息，并且我认为 JComboBox 计算其关于最长项目的宽度？我希望您理解我的问题，否则请告诉我。

Answer 1

查看Combo Box Popup允许您控制弹出窗口的宽度。可以设置宽度

1. 最大字符串的大小，或
2. 指定最大宽度。

如果字符串大于指定宽度，您可以在弹出窗口中打开滚动。