固定了JComboBox的长度，下拉菜单的内容显示不全！怎么改变下拉菜单的长度

Question

我固定了JComboBox的长度，由于下拉菜单的内容很长所以显示不全！怎么改变下拉菜单的长度，或者用什么办法让它能显示出来

Answer 1

小弟的blog上有关于这个源码,可以去看下, 不知道是不是可以用在你的应用上.
http://blog.csdn.net/bradwoo8621

Answer 2

下拉菜单的长度好象设置不了。
解决方法 或者增加JComboBox的长度
或者可以把JComboBox设置成可编辑的
这样用户就可以得到那个超长的内容了

Answer 3

我现在用的方法是使用ToolTip，给每个下拉菜单选项加上ToolTip，超长的部分在ToolTip上就可以看到了

Answer 4

添加ToolTip，只需要给JComboBox添加一个Renderer，
继承BasicComboBoxRenderer类，重写其方法
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus)
    class CustomComboBoxRenderer extends BasicComboBoxRenderer
    {
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected,
                boolean cellHasFocus)
        {
            if (isSelected)
            {
                setBackground(list.getSelectionBackground());
                setForeground(list.getSelectionForeground());
                if (-1 < index)
                {
                    list.setToolTipText((value == null) ? null : value.toString());
                }
            }
            else
            {
                setBackground(list.getBackground());
                setForeground(list.getForeground());
            }
            setFont(list.getFont());
            setText((value == null) ? "" : value.toString());
            return this;
        }
    }接着设置RenderercomboBox.setRenderer(new CustomComboBoxRenderer());

Answer 5

//下面这段代码在JDK1.4测试通过，或许对你有用
package testtools;import java.awt.*;
import javax.swing.*;import javax.swing.plaf.basic.*;public class TestJComboBoxJTable {    public static void main(String[] args) {
        class myCombo
            extends JComboBox {
            public myCombo() {
                super();
                setUI(new myComboUI());
            } //end of default constructor            class myComboUI
                extends BasicComboBoxUI {
                protected ComboPopup createPopup() {
                    BasicComboPopup popup = new BasicComboPopup(comboBox) {
                        protected JScrollPane createScroller() {
                            return new JScrollPane(list,
                                ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
                                ScrollPaneConstants.
                                HORIZONTAL_SCROLLBAR_AS_NEEDED);
                        } //end of method createScroller
                    };
                    return popup;
                } //end of method createPopup
            } //end of inner class myComboUI
        }
        JFrame aFrame = new JFrame();
        myCombo JComboBox1 = new myCombo();
        JComboBox1.setPreferredSize(new Dimension(20, 20));
        JComboBox1.setMaximumSize(new Dimension(30, 20));
        String[] aArr = {
            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
            "BBAAAAAAAAAAA", "CCCCC", "DDDDDDDDDDDDD", "EEEEEEEEEEEE",
            "FFFFFFFFFFFFFFFFFFFFFFFFFFFF",
            "GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG",
            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", "BBAAAAAAAAAAA",
            "CCCCC", "DDDDDDDDDDDDD", "EEEEEEEEEEEE",
            "FFFFFFFFFFFFFFFFFFFFFFFFFFFF",
            "GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG"};
        for (int i = 0; i < aArr.length; ++i)
            JComboBox1.addItem(aArr[i]);
        aFrame.getContentPane().add(JComboBox1);
        aFrame.getContentPane().setSize(100, 100);
        aFrame.pack();
        aFrame.setVisible(true);
    }
}