JScrollpane 使用可变大小的内容调整大小

2022-09-04 22:49:09

我的可调整大小的JScrollPane的内容具有最小宽度。如果 JScrollPane 小于此宽度,则应显示水平滚动条。如果它大于此宽度,视口内容应展开以填充整个视口。

似乎是一个简单的概念,我有一些工作,但它感觉像一个黑客:

import javax.swing.*;
import java.awt.*;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;

public class SSBTest {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                final Component view = new MyView();
                final JScrollPane jScrollPane = new JScrollPane(view);
                jScrollPane.addComponentListener(new ComponentAdapter() {
                    @Override
                    public void componentResized(final ComponentEvent e) {
                        final Dimension minimumSize = view.getMinimumSize();
                        final int width = Math.max(minimumSize.width, jScrollPane.getViewport().getWidth());
                        view.setPreferredSize(new Dimension(width, minimumSize.height));
                    }
                });
                showInDialog(jScrollPane);
            }
        });
    }

    private static void showInDialog(final JScrollPane jScrollPane) {
        final JDialog dialog = new JOptionPane(jScrollPane).createDialog("JScrollPane Resize Test");
        dialog.setResizable(true);
        dialog.setModal(true);
        dialog.setVisible(true);
        System.exit(0);
    }

    private static final class MyView extends JPanel {
        @Override
        protected void paintComponent(final Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.RED);
            g.drawString("Dimensions are " + getSize(), 10, 20);
            g.drawRect(0, 0, getMinimumSize().width-1, getMinimumSize().height-1);
            g.setColor(Color.BLUE);
            g.drawRect(0, 0, getPreferredSize().width-1, getPreferredSize().height-1);
        }

        @Override
        public Dimension getMinimumSize() {
            return new Dimension(200, 200);
        }

        @Override
        public Dimension getPreferredSize() {
            return super.getPreferredSize();
        }
    }
}

调整对话框大小会触发 ComponentListener,该列表显式设置视口视图的首选大小,从而触发组件验证。但是,调整大小会导致滚动条抖动。有没有更清洁的方法可以做到这一点?

编辑:感谢 camickr 的 ScrollablePanel 链接,我修改了我的 JPanel 类来实现 Scrollable,并动态更改 getScrollableTracksViewportWidth() 的返回值。

当视区很大时,我返回 ,告诉 JScrollPane 用我的组件填充视图。当视口很小时,我返回,因此滚动条出现。truegetScrollableTracksViewportWidth()false

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

public class SSBTest {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                final Component view = new MyView();
                final JScrollPane jScrollPane = new JScrollPane(view);
                showInDialog(jScrollPane);
            }
        });
    }

    private static void showInDialog(final JScrollPane jScrollPane) {
        final JDialog dialog = new JOptionPane(jScrollPane).createDialog("JScrollPane Resize Test");
        dialog.setResizable(true);
        dialog.setModal(true);
        dialog.setVisible(true);
        System.exit(0);
    }

    private static final class MyView extends JPanel implements Scrollable {
        @Override
        protected void paintComponent(final Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.RED);
            g.drawString("MyView: " + getWidth() + "x" + getHeight(), 10, 20);
            g.drawRect(0, 0, getMinimumSize().width-1, getMinimumSize().height-1);
            g.setColor(Color.BLUE);
            g.drawRect(0, 0, getPreferredSize().width-1, getPreferredSize().height-1);
            g.drawString("Preferred/Minimum Size", 10, getPreferredSize().height/2);
            g.setColor(Color.GREEN);
            g.drawLine(0, 0, getWidth(), getHeight());
        }

        @Override
        public Dimension getMinimumSize() {
            return new Dimension(200, 200);
        }

        @Override
        public Dimension getPreferredSize() {
            return getMinimumSize();
        }

        public Dimension getPreferredScrollableViewportSize() {
            return getPreferredSize();
        }

        public int getScrollableUnitIncrement(final Rectangle visibleRect, final int orientation, final int direction) {
            return 10;
        }

        public int getScrollableBlockIncrement(final Rectangle visibleRect, final int orientation, final int direction) {
            return visibleRect.width;
        }

        public boolean getScrollableTracksViewportWidth() {
            final Container viewport = getParent();
            return viewport.getWidth() > getMinimumSize().width;
        }

        public boolean getScrollableTracksViewportHeight() {
            return true;
        }

    }
}

答案 1

不确定,但您可以使用可滚动面板。您可以配置组件大小调整(尝试使用 STRETCH)。代码适用于组件的首选大小,而不是最小大小,因此它可能不完全是您想要的。


答案 2