java – JScrollpane使用可变大小的内容调整大小

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,则应扩展视口内容以填满整个视口.

看起来像一个简单的概念,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,getMinimumSize().width-1,getMinimumSize().height-1);
            g.setColor(Color.BLUE);
            g.drawRect(0,getPreferredSize().width-1,getPreferredSize().height-1);
        }

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

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

调整对话框的大小触发ComponentListener,它显式地设置视口视图的首选大小,触发组件验证.然而,调整大小会导致抖动滚动条.有没有更清洁的方法来做到这一点？

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

当视口大时,我返回true为getScrollableTracksViewportWidth(),告诉JScrollPane填充视图与我的组件.当视口很小时,我返回false,所以滚动条出现.

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(),getPreferredSize().height-1);
            g.drawString("Preferred/Minimum Size",getPreferredSize().height/2);
            g.setColor(Color.GREEN);
            g.drawLine(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 direction) {
            return visibleRect.width;
        }

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

        public boolean getScrollableTracksViewportHeight() {
            return true;
        }

    }
}

解决方法

（编辑：安卓应用网）

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