换行的JTextArea报告JDialog包的首选大小不正确？

Question

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.BoxLayout;
import javax.swing.JDialog;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.Scrollable;

public class DisplayPopup extends JDialog {

    public DisplayPopup() {

        JPanel actual = new JPanel(); 
        actual.setLayout(new BoxLayout(actual, BoxLayout.Y_AXIS));
        actual.setOpaque(false);

        JTextArea jta = new JTextArea();
        jta.setText("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed ac dictum magna. Nam sed mattis sem. Donec tortor felis, finibus in lectus fringilla, semper finibus turpis. ");
        jta.setFont(new java.awt.Font("Arial", 0, 18));
        jta.setForeground(new java.awt.Color(204, 204, 204));
        jta.setLineWrap(true);
        jta.setWrapStyleWord(true);
        jta.setEditable(false);
        jta.setBackground(new Color(45,45,45));
        jta.setHighlighter(null);
        actual.add(jta);

        PopupScroll ps = new PopupScroll(actual);

        JScrollPane scroll = new JScrollPane(); 
        scroll.getViewport().add(ps);

        setModalityType(java.awt.Dialog.ModalityType.MODELESS);
        setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        setResizable(false);
        setLocationRelativeTo(null);
        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(scroll);

        pack();
    }

    public static void launch() {
        DisplayPopup dp = new DisplayPopup();
        dp.setVisible(true);
    }

    public static void main(String[] args) {                                                    
        javax.swing.SwingUtilities.invokeLater(DisplayPopup::launch);                                                                                       
    } 

    private class PopupScroll extends JPanel implements Scrollable {

        public PopupScroll(JPanel jp) {
            setBackground(Color.PINK);
            setLayout(new BorderLayout());
            add(jp);
        }

        @Override
        public Dimension getPreferredScrollableViewportSize() {
            return new Dimension(500,Math.min((int)getPreferredSize().getHeight(),700));
        }

        @Override
        public int getScrollableUnitIncrement(Rectangle arg0, int arg1, int arg2) {
            return 1;
        }

        @Override
        public int getScrollableBlockIncrement(Rectangle arg0, int arg1, int arg2) {
            return 1;
        }

        @Override
        public boolean getScrollableTracksViewportWidth() {
            return true; 
        }

        @Override
        public boolean getScrollableTracksViewportHeight() {
            return false;
        }

    }

}

Answer 1

做了一些更改,我看到文本显示在3行上：

pack();
pack();

是的，这是正确的，我添加了第二个包（）。第一个包似乎识别宽度，第二个包导致文本被包装。

然而，我也不得不改变：

//actual.setLayout(new BoxLayout(actual, BoxLayout.Y_AXIS));
actual.setLayout(new BorderLayout());

//actual.setLayout(new BoxLayout(actual, BoxLayout.Y_AXIS));
RelativeLayout rl = new RelativeLayout(RelativeLayout.Y_AXIS);
rl.setFill( true );
actual.setLayout( rl );