如何在JPanel绘画方法的顶部添加图像？

Question

I am having trouble inserting an image on top of a paint method that I've written. I want to have images overlap the paint method at certain coordinates.

My code:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Polygon;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class testguipaint {

    public static void main(String[] args) {
        testguipaint img = new testguipaint();
    }   
    public testguipaint() {
        JFrame frame = new JFrame();
        frame.add(crafting, BorderLayout.CENTER);
        frame.setSize(442, 284);
        frame.setLocationRelativeTo(null);
        frame.setResizable(false);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(3);
    }

    static JPanel crafting = new JPanel() {
        public void paint(Graphics g) {
            Color darkGrey = new Color(153, 153, 153);
            g.setColor(darkGrey);
            g.fillRect(0, 0, 436, 252);
            Color lightGrey = new Color(198, 198, 198);
            g.setColor(lightGrey);
            g.fill3DRect(3, 3, 430, 246, true);
            g.setColor(darkGrey);
            g.fill3DRect(16, 16, 222, 222, true);
            g.fill3DRect(320, 78, 100, 100, true);
            g.fillRect(248, 121, 39, 12);
            Polygon triangle = new Polygon();
            triangle.addPoint(287, 103);
            triangle.addPoint(287, 151);
            triangle.addPoint(311, 127);
            g.fillPolygon(triangle);
            g.setColor(Color.white);
            g.fill3DRect(88, 16, 3, 222, true);
            g.fill3DRect(163, 16, 3, 222, true);
            g.fill3DRect(16, 88, 222, 3, true);
            g.fill3DRect(16, 163, 222, 3, true);
            //BufferedImage image = new ImageIO.read(new File("/minecraft jpeg's/Products/Bread.png"));
            //g.drawImage(image, 44, 191, null);
            //44, 191
        }
    };      
}

Answer 1

Just a suggestion, paint the images last in the paint component. This would allow the images to by drawn on top of the other objects. Also, I know that you were probably just testing something, but the first letter of every word in your class name should be capitalized.

Answer 2

not an answer how to overlay or overlap

1) testguipaint should be TestGuiPaint more about Java Naming Conventions here or here

2) Swing GUI rellated code should be wrapped into invokeLater() , more about in the Initial Threads

3) for painting in Swing JComponents there is method paintComponent() instead of paint() method, more about in the 2D Graphics

Answer 3

Condensing the imports only for short code here, implementing only 2 of the suggestions MKorbel made (1 and 3), extending JFrame for brevity too, removed instance from main, which was never used. Nothing you asked for.

But you surely don't want to have the image read over and over again from HDD, each time the Panel needs repainting. So we create an instance which holds an attribute, which is the image.

import java.awt.*;
import javax.swing.*;
import javax.swing.JPanel;
import java.awt.image.*;
import javax.imageio.*;
import java.io.*;

public class TestGuiPaint extends JFrame {

    public static void main (String [] args) {
        new TestGuiPaint ();
    }   
    public TestGuiPaint () {
    super ("TestGuiPaint"); 
        add (new CraftingPanel (), BorderLayout.CENTER);
        setSize (442, 284);
        setLocationRelativeTo (null);
        setResizable (false);
        setVisible (true);
        setDefaultCloseOperation (3);
    }

    class CraftingPanel extends JPanel {
    BufferedImage image = null;
        public CraftingPanel () {
        try {
            image = ImageIO.read (new File ("./maeander3.png"));
        } catch (java.io.IOException ioe) 
        {
            System.err.println (ioe.getMessage ());
        }       
        }

        public void paintComponent (Graphics g) {
            Color darkGrey = new Color (153, 153, 153);
            g.setColor (darkGrey);
            g.fillRect (0, 0, 436, 252);
            Color lightGrey = new Color (198, 198, 198);
            g.setColor (lightGrey);
            g.fill3DRect (3, 3, 430, 246, true);
            g.setColor (darkGrey);
            g.fill3DRect (16, 16, 222, 222, true);
            g.fill3DRect (320, 78, 100, 100, true);
            g.fillRect (248, 121, 39, 12);
            Polygon triangle = new Polygon ();
            triangle.addPoint (287, 103);
            triangle.addPoint (287, 151);
            triangle.addPoint (311, 127);
            g.fillPolygon (triangle);
            g.setColor (Color.white);
            g.fill3DRect (88, 16, 3, 222, true);
            g.fill3DRect (163, 16, 3, 222, true);
            g.fill3DRect (16, 88, 222, 3, true);
            g.fill3DRect (16, 163, 222, 3, true);
        g.drawImage (image, 44, 191, null);
        }
    };      
}

I hope you understand that I've chosen a different filename for the image. :)