JComboBox更改下拉式弹出式窗口

问题描述

基本上是一个的弹出式窗口，显示在其派生的JTextField，如何从JComboBox弹出窗口的方向改变方向，并在顶部/底部显示JComboBox的弹出窗口。

basically is popup for a JComboBox displayed below its derived JTextField, how can change direction from bellowed orientations for JComboBox's popup and display JComboBox's popup on the top/over that

编辑：基本JComboBox的代码示例

code example for basic JComboBox

import java.awt.Dimension;
import javax.swing.*;
import javax.swing.plaf.basic.BasicComboBoxRenderer;

public class HighRowCombo {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new HighRowCombo().makeUI();
            }
        });
    }

    public void makeUI() {
        Object[] data = {"One", "Two with text", "Three with long text, with long text,with long text "};
        JComboBox comboBox = new JComboBox(data);
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.add(comboBox);
        frame.pack();
        BasicComboBoxRenderer renderer = (BasicComboBoxRenderer) comboBox.getRenderer();
        Dimension size = renderer.getPreferredSize();
        size.height += 50;
        renderer.setPreferredSize(size);
        frame.setVisible(true);
    }
}

编辑第二。 MacOX代码

EDIT 2nd. Code for MacOX

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

public class TestHighRow {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
                } catch (Exception e) {
                    e.printStackTrace();
                }
                new TestHighRow().makeUI();
            }
        });
    }

    public void makeUI() {
        Object[] data = {"One", "Two", "Three"};
        JComboBox comboBox = new JComboBox(data);
        comboBox.setPreferredSize(comboBox.getPreferredSize());
        comboBox.setRenderer(new HighRowRenderer(comboBox.getRenderer()));
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(comboBox);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static class HighRowRenderer implements ListCellRenderer {

        private final ListCellRenderer delegate;
        private int height = -1;

        public HighRowRenderer(ListCellRenderer delegate) {
            this.delegate = delegate;
        }

        @Override
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
            Component component = delegate.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            Dimension size = component.getPreferredSize();
            if (height == -1) {
                height = size.height + 50;
            }
            size.height = height;
            component.setPreferredSize(size);
            if (component instanceof JLabel) {
                ((JLabel) component).setHorizontalTextPosition(JLabel.CENTER);
            }
            return component;
        }
    }
}

推荐答案

尝试在组合框弹出窗口中找到的setPopupAbove（）方法/ a>。

Try the setPopupAbove() method found in Combo Box Popup.

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