Question

我正在编写一些代码来创建文本的彩色可视化。以下管理可视化面板，并且（正确地）从程序中的其他位置调用setCT（String c）方法。

不幸的是，只有在调整窗口大小时才会发生所需的可视化。在那之前，vis面板保持黑色！到底是怎么回事？我已尝试使用validate（）方法，并根据其他指南创建一个新的Runnable（），但无济于事。这是我的代码：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;

import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class Visualiser extends JPanel implements ActionListener {

    /**
     * 
     */
    private static final long serialVersionUID = -3936526023655045114L;
    public static final Color DEFAULT_BG_COL = Color.black;
    private static Color bgCol;
    private static String ct;
    private static BufferedImage stat;
    private static boolean doVis=false;
    private Timer refreshTimer=new Timer(100, this);

    public Visualiser() {
        this(200, 250);
    }

    public Visualiser(int w, int h) {

        super.setSize(new Dimension(w, h));
        super.setPreferredSize(new Dimension(w, h));
        bgCol = Visualiser.DEFAULT_BG_COL;      
        super.setBackground(bgCol);
        stat = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
        refreshTimer.start();


    }


    /*public void paint(Graphics g) {
     * REPLACED BY paintComponent() METHOD AS PER SUGGESTION
        super.paint(g);
        if (Visualiser.doVis==true) {
            System.out.println("passed doVis test");
            doVis(g);
        }

    }*/

    public void paintComponent(Graphics g) {
        if(Visualiser.doVis) {
            doVis(g);
        }
    }

    public Color getBGCol() {
        return bgCol;
    }

    public void setBGCol(Color b) {
        bgCol = b;
        super.setBackground(bgCol);
    }

    public void doVis(Graphics g) {
        // all of my code to actually paint the visualisation is here
        //doStatic(g);
        // establish the block size and height using length of the string
        int numBlocks = 3*ct.length();
        if (numBlocks != 0) {
            int blockSize = (int) Math.sqrt((this.getWidth()*this.getHeight())/numBlocks) ;
            Graphics2D g2 = stat.createGraphics();
            int blocksX=Math.round(this.getWidth()/blockSize);
            int blocksY=Math.round(this.getHeight()/blockSize);
            char chars[]=ct.toCharArray();
            int c=0;
            int cc=0;
            for(int i = 1; i< blocksX; i++) {
                for(int j=1; j<blocksY; j++) {
                    cc=c+4;
                    if(cc < chars.length) {
                        //System.out.println("char length is: " + chars.length + " and c is: " + c);
                        g2.setColor(new Color((int) chars[c]%255, (int) chars[c+1]%255, (int)chars[c+2]%255));
                        //System.out.println("color: " + g2.getColor().toString());
                    }
                    g2.fill(new Rectangle2D.Double(i*blockSize, j*blockSize, blockSize, blockSize));
                    c++;
                }
            }

            g.drawImage(stat, 0, 0, this);
        }




    }

    private void doStatic(Graphics g) {
        Graphics2D g2 = stat.createGraphics();
        int x=this.getWidth();
        int y=this.getHeight();
        //System.out.println("x, y: " + x + " " + y);
        for (int i=1; i<x; i++) {
            for(int j=1; j<y; j++) {
                g2.setColor(new Color(getRandom(0, 255), getRandom(0,255), getRandom(0,255)));
                g2.fill(new Rectangle2D.Double(i, j, 1, 1));
            }
        }
        g.drawImage(stat,  0, 0, this);

    }


    private int getRandom(int min, int max) {
        int random = min + (int) (Math.random() * (max - min));

        return random;

    }


    public void setCT(String c) {
        Visualiser.doVis=true;
        ct=c;
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                System.out.println("got to the new runnable thingie");

                repaint();
            }
        });


    }

    public void actionPerformed(ActionEvent e) {
        if(e.getSource().equals(this.refreshTimer)) {
            // the timer is the source so do some refreshing!

            repaint();
        }

    }




}

doVis和ct变量都是public static boolean＆amp;分别为此（Visualiser）类的字符串和paint方法在决定绘制内容之前检查doVis值。这部分还可以。它迫使Java进行适当的重绘，这就是问题所在！

Answer 1

当你扩展JPanel时，快速，简单和干净的方式来实现你想要的是覆盖你进行渲染的JPanel.paintComponent()方法。

如果你想自动刷新你的GUI，那么我建议你选择不时调用JPanel.validate()的摇摆计时器。您的面板可能如下所示：

public class TextRendererPanel extends JPanel{
   protected void paintComponent(Graphics g){
       // Do your rendering stuff here.
   }
}

创建完成后，面板可以像这样刷新：

TextRendererPanel textRendererPanel = new TextRendererPanel();
textRendererPanel.invalidate();

这是一个tutorial关于挥杆计时器，你可以从这开始。

Java：无法重绘（）？

1 个答案: