当帧太小而无法显示所有JList时,如何让滚动条出现在JList上？

Question

每当帧的大小调整为对于List本身而言太小时,我想让JList上出现一个滚动条.到目前为止,这是我的代码.运行它,调整框架大小,并注意JList上没有滚动条的显示方式.

import java.awt.Dimension;

import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;


public class JListScroll extends JPanel{

JScrollPane listScrollPane;

public JListScroll() {
    String[] stringArray = {"Testing","This","Stuff"};
    JList<String> rowList = new JList<String>(stringArray);
    listScrollPane = new JScrollPane();
    listScrollPane.getViewport().setView(rowList);
    this.setSize(new Dimension(75,200));
    this.add(listScrollPane);
    this.doLayout();
}

public static void main(String[] args){
    JFrame frame = new JFrame();
    JListScroll scrollPanel = new JListScroll();
    frame.add(scrollPanel);
    frame.setVisible(true);
    frame.setSize(new Dimension(75,300));
}

}

请注意如何添加JScrollPane,但当窗口变得非常小时,列表中不会显示滚动条.这是我想要解决的问题.

提前致谢!

Answer 1

• JPanel实现了FlowLayout

• FlowLayout仅接受PreferredSize(在您的情况下由setSize硬编码)

• 没有指定FlowLayout,没有实现任何调整大小的JComponents(由FlowLayout布局)和容器,JComponent不可调整大小,保持原样

• 不想评论你在这里发布的代码,看到差异,相当不错的低级别

import java.awt.BorderLayout;
import java.awt.Dimension;    
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class JListScroll {

    private JFrame frame = new JFrame();
    private JPanel panel = new JPanel();
    private JScrollPane listScrollPane = new JScrollPane();
    private String[] stringArray = {"Testing", "This", "Stuff"};
    private JList rowList = new JList(stringArray);

    public JListScroll() {
        rowList.setVisibleRowCount(2);
        listScrollPane.setViewportView(rowList);
        panel.setLayout(new BorderLayout());
        panel.add(listScrollPane);
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // EDIT 
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JListScroll jListScroll = new JListScroll();
            }
        });
    }
}