使用图像制作自定义JScrollBar

Question

因此,我使用Java Swing为我的应用程序构建UI,并使用自定义图像来替换丑陋的Java,自定义图像具有样式,并且非常容易集成到Java Swing中.

现在我的问题是我需要在应用程序中使用a JScrollBar,JScrollPane我真的不想使用默认的Java Scroll Bar甚至本机OS Scroll Bar.

我只是希望能够将自定义图像作为滚动条的背景和图像作为滚动条的拇指.

如何使用图像制作自定义JScrollBar？

Answer 1

我写了一个示例,演示如何为滚动条的拇指和背景(称为轨道)设置自定义图像.您需要两个文件thumb.png以及track.png类文件所在位置的自定义图像.我还对图像进行了一些缩放以适应滚动条.只是尝试一下这段代码.我更改了滚动条的宽度(setPreferredSize)以更好地查看图像.

基本点是,你必须创建自己的类MyUi扩展BasicScrollBarUI和覆盖paintThumb和paintTrack,并与个性化的滚动条setUI(new MyUI):

import java.awt.*;
import java.io.FileReader;
import java.io.IOException;
import javax.swing.*;
import javax.swing.plaf.metal.MetalScrollBarUI;
import javax.imageio.ImageIO;
import java.io.File;
import java.awt.geom.AffineTransform;


public class CustomScrollbarUIExample {
  public static void main(String[] args) {
    JScrollPane before = makeExamplePane();
    JScrollPane after = makeExamplePane();  

    JScrollBar sb=after.getVerticalScrollBar();
    sb.setPreferredSize(new Dimension(50, Integer.MAX_VALUE));
    sb.setUI(new MyScrollbarUI());

    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    Container c = f.getContentPane();
    c.setLayout(new GridLayout(2, 1, 0, 1));
    c.add(before);
    c.add(after);
    f.setSize(450, 400);
    f.setVisible(true);
  }

  private static JScrollPane makeExamplePane() {
    String exampleText= "Lorem ipsum dolor sit amet,\n consetetur sadipscing elitr,\n sed diam nonumy eirmod \ntempor invidunt ut labore et dolore \nmagna aliquyam erat,\n sed diam voluptua. At vero eos et accusam et \njusto duo dolores et ea rebum. Stet clita\n kasd gubergren, no sea\n takimata sanctus est Lorem ipsum dolor sit amet.\n Lorem ipsum dolor sit amet,\n consetetur sadipscing elitr, sed diam\n nonumy eirmod tempor invidunt \nut labore et dolore\n magna aliquyam erat, sed diam voluptua.\n At vero eos et accusam et justo \nduo\n dolores et ea rebum. Stet clita kasd gubergren, no sea\n takimata sanctus est Lorem\n ipsum dolor sit amet. Lorem ipsum dolor\n sit amet, consetetur sadipscing elitr,\n sed diam nonumy\n eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos\n et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est \nLorem ipsum dolor sit amet.Duis\n autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel\n illum dolore eu feugiat nulla facilisis at vero eros et \naccumsan et iusto odio \ndignissim qui blandit praesent luptatum zzril delenit augue\n duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer\n adipiscing elit, sed diam nonummy nibh euismod \ntincidunt ut laoreet\n dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam,\n quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea\n commodo consequat. Duis autem vel eum iriure \ndolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla \nfacilisis at vero eros et accumsan et iusto odio dignissim qui blandit\n praesent luptatum zzril delenit augue duis dolore \nte feugait nulla facilisi.";
    JTextArea text = new JTextArea(exampleText);
    JScrollPane scroll = new JScrollPane(text);
    return scroll;
  }

  static class MyScrollbarUI extends MetalScrollBarUI {
    private Image imageThumb, imageTrack;
    MyScrollbarUI() {
        try {
            imageThumb = ImageIO.read(new File("thumb.png"));
            imageTrack = ImageIO.read(new File("track.png"));
        } catch (IOException e){}
    }

    @Override
    protected void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds) {        
        g.translate(thumbBounds.x, thumbBounds.y);
        g.setColor( Color.red );
        g.drawRect( 0, 0, thumbBounds.width - 2, thumbBounds.height - 1 );
        AffineTransform transform = AffineTransform.getScaleInstance((double)thumbBounds.width/imageThumb.getWidth(null),(double)thumbBounds.height/imageThumb.getHeight(null));
        ((Graphics2D)g).drawImage(imageThumb, transform, null);
        g.translate( -thumbBounds.x, -thumbBounds.y );
    }

    @Override
    protected void paintTrack(Graphics g, JComponent c, Rectangle trackBounds) {        
        g.translate(trackBounds.x, trackBounds.y);
        ((Graphics2D)g).drawImage(imageTrack,AffineTransform.getScaleInstance(1,(double)trackBounds.height/imageTrack.getHeight(null)),null);
        g.translate( -trackBounds.x, -trackBounds.y );
    }

  }
}

有关更多信息,请参阅sourcefile MetalScrollBarUI.java.

Answer 2

按钮仍然是一个小的灰色区域,但我不知道如何删除这个.

这是@ halex示例的一个变体,它删除按钮并让图形上下文进行缩放.我添加了一个虚假图像,使示例自包含.

import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.plaf.metal.MetalScrollBarUI;

/** @see http://stackoverflow.com/a/12270067/230513 */
public class CustomScrollbarUIExample {

    public static void main(String[] args) {
        JScrollPane before = makeExamplePane();
        JScrollPane after = makeExamplePane();
        JScrollBar sb = after.getVerticalScrollBar();
        sb.setUI(new MyScrollbarUI());
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setLayout(new GridLayout(0,1));
        f.add(before);
        f.add(after);
        f.pack();
        f.setSize(320, 240);
        f.setVisible(true);
    }

    private static JScrollPane makeExamplePane() {
        JTextArea text = new JTextArea(16, 16);
        text.append("Lorem ipsum dolor sit amet…");
        JScrollPane scroll = new JScrollPane(text);
        return scroll;
    }

    static class MyScrollbarUI extends MetalScrollBarUI {

        private Image imageThumb, imageTrack;
        private JButton b = new JButton() {

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(0, 0);
            }

        };

        MyScrollbarUI() {
            imageThumb = FauxImage.create(32, 32, Color.blue.darker());
            imageTrack = FauxImage.create(32, 32, Color.lightGray);
        }

        @Override
        protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
            g.setColor(Color.blue);
            ((Graphics2D) g).drawImage(imageThumb,
                r.x, r.y, r.width, r.height, null);
        }

        @Override
        protected void paintTrack(Graphics g, JComponent c, Rectangle r) {
            ((Graphics2D) g).drawImage(imageTrack,
                r.x, r.y, r.width, r.height, null);
        }

        @Override
        protected JButton createDecreaseButton(int orientation) {
            return b;
        }

        @Override
        protected JButton createIncreaseButton(int orientation) {
            return b;
        }
    }

    private static class FauxImage {

        static public Image create(int w, int h, Color c) {
            BufferedImage bi = new BufferedImage(
                w, h, BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = bi.createGraphics();
            g2d.setPaint(c);
            g2d.fillRect(0, 0, w, h);
            g2d.dispose();
            return bi;
        }
    }
}