ScrollBar在Swing中的JScrollpane中移动不流畅

Question

我有这样的情况。我有其viewportView是JPanel的滚动窗格，并且该JPanel的布局为BoxLayout。在此面板中，我添加了一个扩展JPanel的类，该类包含JComponents。

因此，在运行应用程序时，JScrollPane中将显示JComponents。这就是我的ScrollPane的形成方式。

这里的问题是，当数据超过大约750行时，滚动条开始出现问题。当通过鼠标滚轮上下滚动时，滚动不会平稳地移动，它突然在中间停止，然后再次开始，说它有一个急促的运动。我的问题是在这种情况下如何获得平滑的鼠标移动。

我的scrollPane是这样的

public JScrollPane getScrollPane() {
    if (scrollPane == null) {
        scrollPane = new JScrollPane();
        scrollPane.setSize(new Dimension(1000, 433));
        scrollPane.setLocation(new Point(10, 10));
        scrollPane.setColumnHeaderView(getHeaderOfRowPanel());
        scrollPane
                .setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        scrollPane.setViewportView(getScrollPanel());
        scrollPane
                .setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        scrollPane.getVerticalScrollBar().setUnitIncrement(
                unitIncrement);

    }
    return scrollPane;
}

private JPanel getScrollPanel() {
    if (scrollPanel == null) {
        scrollPanel = new JPanel();
        scrollPanel.setBorder(null);
        scrollPanel.setLayout(new BoxLayout(getScrollPanel(),
                BoxLayout.Y_AXIS));
    }
    return scrollPanel;
}


private class RowPanel extends JPanel {
//My components are here ..
//I add this Panel in scrollPanel
}

Answer 1

看一下JScrollBar.setUnitIncrement，因为与JPanels中的一堆JScollPane相比有不自然的滚动JList，JTable或者JTextArea

例

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

public class JScrollBarUnitIncrement {

    public static void main(String[] args) {
        final JFrame f = new JFrame("");
        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(2000, 1));
        for (int i = 0; i != 2000; i++) {
            JButton btn = new JButton("Button 2");
            panel.add(btn);
        }
        final JScrollPane sPane = new JScrollPane(panel);
        final int increment = 50;
        sPane.getVerticalScrollBar().setUnitIncrement(increment);
        KeyStroke kUp = KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0);
        KeyStroke kDown = KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0);
        sPane.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(kUp, "actionWhenKeyUp");
        sPane.getActionMap().put("actionWhenKeyUp", new AbstractAction("keyUpAction") {

            private static final long serialVersionUID = 1L;

            public void actionPerformed(ActionEvent e) {
                final JScrollBar bar = sPane.getVerticalScrollBar();
                int currentValue = bar.getValue();
                bar.setValue(currentValue - increment);
            }
        });
        sPane.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(kDown, "actionWhenKeyDown");
        sPane.getActionMap().put("actionWhenKeyDown", new AbstractAction("keyDownAction") {

            private static final long serialVersionUID = 1L;

            public void actionPerformed(ActionEvent e) {
                final JScrollBar bar = sPane.getVerticalScrollBar();
                int currentValue = bar.getValue();
                bar.setValue(currentValue + increment);
            }
        });
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(sPane);
        f.pack();
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                f.setVisible(true);
            }
        });
    }

    private JScrollBarUnitIncrement() {
    }
}