Java Swing:鼠标悬停在JComboBox项目上的文本？

Question

在Swing中,有没有办法为JComboBox中的每个项目定义鼠标悬停文本(或工具提示文本)？

Answer 1

有一个比ToolTipComboBox已经给出的答案更好的方法来做到这一点.

首先,做一个自定义ListCellRenderer:

package com.example;

import javax.swing.*;
import java.awt.*;
import java.util.List;

public class ComboboxToolTipRenderer extends DefaultListCellRenderer {
    List<String> tooltips;

    @Override
    public Component getListCellRendererComponent(JList list, Object value,
                        int index, boolean isSelected, boolean cellHasFocus) {

        JComponent comp = (JComponent) super.getListCellRendererComponent(list,
                value, index, isSelected, cellHasFocus);

        if (-1 < index && null != value && null != tooltips) {
            list.setToolTipText(tooltips.get(index));
        }
        return comp;
    }

    public void setTooltips(List<String> tooltips) {
        this.tooltips = tooltips;
    }
}

然后像这样使用它:

JComboBox comboBox = new JComboBox();
ComboboxToolTipRenderer renderer = new ComboboxToolTipRenderer();
comboBox.setRenderer(renderer);
...
//make a loop as needed
comboBox.addItem(itemString);
tooltips.add(tooltipString);
...
renderer.setTooltips(tooltips);

Answer 2

我喜欢MountainX解决方案的简单性,但不喜欢缺少封装.另一种具有更多移动部件的解决方案,但它们非常简单且可重复使用.

界面:

public interface ToolTipProvider {
    public String getToolTip();
}

包装类:

public class ToolTipWrapper implements ToolTipProvider {
    final Object value;
    final String toolTip;

    public ToolTipWrapper(Object value, String toolTip) {
        this.value = value;
        this.toolTip = toolTip;
    }

    @Override
    public String getToolTip() {
        return toolTip; 
    }

    @Override
    public String toString() {
        return value.toString();
    }

}

和MountainX的渲染器的变体:

public class ToolTipRenderer extends DefaultListCellRenderer {

    @Override
    public Component getListCellRendererComponent(JList list, Object value,
            int index, boolean isSelected, boolean cellHasFocus) {
         JComponent component = (JComponent) super.getListCellRendererComponent(list, value, index, isSelected,
                cellHasFocus);
         String tip = null;
         if (value instanceof ToolTipProvider) {
             ToolTipProvider ttp = (ToolTipProvider) value;
             tip = ttp.getToolTip();
         }
         list.setToolTipText(tip);
         return component;
    }
}

现在添加:

combobox.addItem(new ToolTipWrapper(itemString,tooltipString) );