java - JXMultiSplitPane 在 slider 调整期间导致重新绘制？

Question

在 JXMultiSplitPane 中调整拆分器期间，我似乎经常收到重绘请求. (见下面的程序)

为什么？

我有 setContinuousLayout(false)。

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澄清一下:我知道重绘应该发生在拆分 Pane 大小调整之后。但是在拆分器调整期间，没有调整任何大小；分离器在屏幕上四处移动。

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import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import org.jdesktop.swingx.JXMultiSplitPane;
import org.jdesktop.swingx.MultiSplitLayout;

public class MultiVerticalPane<T extends Component> extends JPanel
{
    final private List<T> components;
    public MultiVerticalPane(List<? extends T> components,
            List<Double> weights)
    {
        this.components = new ArrayList<T>(components);
        final int n = this.components.size();
        if (weights != null && weights.size() != n)
            throw new IllegalArgumentException(
                    "weights and components should have same length");

        JXMultiSplitPane msp = new JXMultiSplitPane();
        msp.setContinuousLayout(false);
        msp.getMultiSplitLayout().setModel(createSplitModel(weights));
        int i = 0;
        for (T component : components)
        {
            msp.add(component, nodeTitle(i++));
        }

        setLayout(new BorderLayout());
        add(msp, BorderLayout.CENTER);
    }
    private MultiSplitLayout.Split createSplitModel(
            List<Double> weights) 
    {
        LinkedList<MultiSplitLayout.Node> nodes = 
            new LinkedList<MultiSplitLayout.Node>();
        int i = 0;
        double wtot = 0;
        for (double w : weights)
        {
            wtot += w;
        }
        for (double w : weights)
        {           
            if (i > 0)
                nodes.addFirst(new MultiSplitLayout.Divider());
            MultiSplitLayout.Leaf leaf = 
                new MultiSplitLayout.Leaf(nodeTitle(i++));
            leaf.setWeight(w/wtot);
            nodes.addFirst(leaf);
        }
        MultiSplitLayout.Split split = 
            new MultiSplitLayout.Split();
        split.setRowLayout(false);
        split.setChildren(nodes);
        return split;
    }
    private String nodeTitle(int i) {
        return String.format("%02d", i);
    }

    /************ test methods *************/

    private interface Painter
    {
        public void paint(Graphics g, Rectangle bounds);
    }

    static private class RelativeGraphics
    {
        final private Graphics g;
        final private double xofs;
        final private double yofs;
        final private double xscale;
        final private double yscale;
        private double cx;
        private double cy;

        public RelativeGraphics(Graphics g, Rectangle bounds)
        {
            this.g = g;
            this.cx = 0;
            this.cy = 0;
            this.xofs = bounds.getMinX();
            this.yofs = bounds.getMaxY();
            this.xscale = bounds.getWidth();
            this.yscale = -bounds.getHeight();
        }
        public void moveTo(double x, double y)
        {
            this.cx = x;
            this.cy = y;
        }
        public void lineTo(double x, double y)
        {
            this.g.drawLine(
                (int)(this.cx*this.xscale+this.xofs),
                (int)(this.cy*this.yscale+this.yofs),
                (int)(x*this.xscale+this.xofs),
                (int)(y*this.yscale+this.yofs)
            );
            moveTo(x,y);
        }           
        public void rmoveTo(double dx, double dy)
        {
            moveTo(this.cx+dx, this.cy+dy);
        }           
        public void rlineTo(double dx, double dy)
        {
            lineTo(this.cx+dx, this.cy+dy);
        }           
    }

    // adapted from http://en.wikipedia.org/wiki/Hilbert_curve#Java
    static private class HilbertCurve
    {
        final private RelativeGraphics rg;
        final private double d;
        public HilbertCurve(RelativeGraphics rg, int level)
        {
            this.rg = rg;
            double d0 = 1.0;
            for (int i = level; i > 0; i--)
                d0 /= 2;
            this.d = d0;
            rg.rmoveTo(d0/2, d0/2);
            drawCurveUp(level);
        }
        private void drawCurveUp(int n) 
        {           
            if (n > 0) {
                drawCurveLeft(n-1);    this.rg.rlineTo(0, this.d);
                drawCurveUp(n-1);      this.rg.rlineTo(this.d, 0);
                drawCurveUp(n-1);      this.rg.rlineTo(0, -this.d);
                drawCurveRight(n-1);
            }
        }

        private void drawCurveLeft(int n)
        {
            if (n > 0) {
                drawCurveUp(n-1);      this.rg.rlineTo(this.d, 0);
                drawCurveLeft(n-1);    this.rg.rlineTo(0, this.d);
                drawCurveLeft(n-1);    this.rg.rlineTo(-this.d, 0);
                drawCurveDown(n-1);
            }
        }

        private void drawCurveRight(int n)
        {
            if (n > 0) {
                drawCurveDown(n-1);     this.rg.rlineTo(-this.d, 0);
                drawCurveRight(n-1);    this.rg.rlineTo(0, -this.d);
                drawCurveRight(n-1);    this.rg.rlineTo(this.d, 0);
                drawCurveUp(n-1);
            }
        }

        private void drawCurveDown(int n)
        {
            if (n > 0) {
                drawCurveRight(n-1);    this.rg.rlineTo(0, -this.d);
                drawCurveDown(n-1);     this.rg.rlineTo(-this.d, 0);
                drawCurveDown(n-1);     this.rg.rlineTo(0, this.d);
                drawCurveLeft(n-1);
            }
        }
    }

    static private class HilbertPainter implements Painter
    {
        final private int level;
        public HilbertPainter(int level) { this.level = level; }
        @Override public void paint(Graphics g, Rectangle bounds) {
            new HilbertCurve(
                new RelativeGraphics(g,
                    new Rectangle(new Point(0,0),bounds.getSize())),
                this.level);
        }
    }

    static private class PainterPanel extends JPanel
    {
        final private Painter painter;

        public PainterPanel(Painter painter)
        {
            this.painter = painter;
            setBackground(Color.WHITE);
            setForeground(Color.RED);
        }
        @Override public void paintComponent(Graphics g) 
        {
            super.paintComponent(g);
            this.painter.paint(g, getBounds());
        }
    }

    public static void main(String[] args) { test(); }
    private static void test() 
    {
        JFrame frame = new JFrame("MultiVerticalPane test");
        List<JPanel> panels = new ArrayList<JPanel>();
        List<Double> weights = Arrays.asList(1.0,1.0,2.0,4.0,8.0);

        for (int i = 0; i < 5; ++i)
        {
            panels.add(new PainterPanel(new HilbertPainter(i+4)
                {
                    int count = 0;
                    @Override public void paint(Graphics g, 
                            Rectangle bounds)
                    {
                        super.paint(g, 
                            new Rectangle(bounds.getLocation(),
                                new Dimension(bounds.width, 
                                    bounds.height-10)));
                        g.drawString(String.format("%d", this.count++),
                                0, bounds.height);
                    }
                }
            ));
        }       
        MultiVerticalPane<Component> mvp = 
            new MultiVerticalPane<Component>(panels, weights);
        mvp.setPreferredSize(new Dimension(360,720));
        frame.setContentPane(mvp);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

Answer 1

看起来 setContinuousLayout() 影响 revalidate()，而不是 repaint()。