GetGraphics() problem

Question

hello guys,
I have some problem in Swing pl help,
What i have to do is draw a image on the JFrame so this is what i did
1. created a class
2. created the JFrame
3. got the image using getImage()
4. tried drawing it using drawImage()
but the image is not drawn
Here is the code
import java.awt.*;
import javax.swing.*;
class canvas12
     JFrame jf;
     Image img;
     Toolkit tk;
     Container cp;
     canvas12()
          jf= new JFrame("hello");
          tk = Toolkit.getDefaultToolkit();
          img = tk.getImage(getClass().getResource("puyo_blue.png"));
          jf.setVisible(true);
          jf.repaint();
     public void repaint()
          Graphics g;
          g = jf.getGraphics();
          System.out.println(g);
          g.drawImage(img,12,34,null);          
     public static void main(String args[])
          canvas12 c=new canvas12();
}now the above class is not totaly correct i know i should have used the paintComponent() method must have subclassed JComponent, the class name is also unappropriate
but i want to do it using repaint() i know there is some error in my code because of which i 'm having problem drawing the image(one should not be using paint() when wortking with Swing)
what i lack is the concept behind the drawing of image i read books but i'm still not clear with the concepts pl help me understand the concept
Pl if you could correct my code and help me understand the point where i'm lacking i would be very gratefull

Answer 1

this is the below code of some other person i downloaded
import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;
// Referenced classes of package Puyo:
//            PuyoLogic, Ball
public class PuyoWindow
    implements KeyListener
    JFrame mainFrame;
    Canvas paintCanvas;
    JLabel labelScore;
    PuyoLogic puyoLogic;
    public Image puyoImages[];
    private Image doubleBuffer;
    public static final int boardWidth = 6;
    public static final int boardHeight = 12;
    public static final int ballWidth = 32;
    public static final int ballHeight = 32;
    public static final int canvasWidth = 192;
    public static final int canvasHeight = 384;
    public PuyoWindow()
        puyoLogic = null;
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        puyoImages = new Image[4];
        puyoImages[0] = toolkit.getImage(getClass().getResource("images/puyo_red.png"));
        puyoImages[1] = toolkit.getImage(getClass().getResource("images/puyo_green.png"));
        puyoImages[2] = toolkit.getImage(getClass().getResource("images/puyo_blue.png"));
        puyoImages[3] = toolkit.getImage(getClass().getResource("images/puyo_yellow.png"));
        mainFrame = new JFrame("PuyoWindow");
        Container cp = mainFrame.getContentPane();
        labelScore = new JLabel("Score:");
        cp.add(labelScore, "North");
        paintCanvas = new Canvas();
        paintCanvas.addKeyListener(this);
        paintCanvas.setSize(192, 384);
        cp.add(paintCanvas, "Center");
        JPanel panelButtom = new JPanel();
        panelButtom.setLayout(new BorderLayout());
        JLabel labelHelp = new JLabel("Start: S; Pause: P/SPACE", 0);
        panelButtom.add(labelHelp, "North");
        labelHelp = new JLabel("Speed: PgUp, PgDn", 0);
        panelButtom.add(labelHelp, "Center");
        labelHelp = new JLabel("Move/Rotate: Arrow keys", 0);
        panelButtom.add(labelHelp, "South");
        cp.add(panelButtom, "South");
        mainFrame.addKeyListener(this);
        //mainFrame.pack();
        mainFrame.setResizable(false);
        //mainFrame.setTitle("Puyo");
        mainFrame.setDefaultCloseOperation(3);
        mainFrame.setVisible(true);
        beginPuyo();
    public void keyPressed(KeyEvent e)
        int keyCode = e.getKeyCode();
        if(puyoLogic.running)
            switch(keyCode)
            case 38: // '&'
                puyoLogic.rotateCW();
                break;
            case 40: // '('
                puyoLogic.rotateCCW();
                break;
            case 37: // '%'
                puyoLogic.moveLeft();
                break;
            case 39: // '\''
                puyoLogic.moveRight();
                break;
            case 33: // '!'
                puyoLogic.speedUp();
                break;
            case 34: // '"'
                puyoLogic.speedDown();
                break;
            case 32: // ' '
            case 80: // 'P'
                puyoLogic.changePauseState();
                break;
        if(keyCode == 83 || keyCode == 10)
            puyoLogic.running = true;
            beginPuyo();
    public void keyReleased(KeyEvent keyevent)
    public void keyTyped(KeyEvent keyevent)
    public void repaint()
        Graphics g = paintCanvas.getGraphics();
        if(doubleBuffer != null)
            Graphics g2 = doubleBuffer.getGraphics();
            g2.setColor(Color.WHITE);
            g2.fillRect(0, 0, 192, 384);
            drawBalls(g2);
            g2.dispose();
            g.drawImage(doubleBuffer, 0, 0, null);
        } else
            doubleBuffer = paintCanvas.createImage(192, 384);
        updateScore();
    private int color2ImageIndex(int color)
        return color - 1;
    private void drawBalls(Graphics g)
label0:
label1:
                if(puyoLogic == null)
                    break label0;
                int i = 0;
                do
                    PuyoLogic _tmp = puyoLogic;
                    if(i >= 2)
                        break label1;
                    g.drawImage(puyoImages[color2ImageIndex(puyoLogic.droppingBalls.color)], (puyoLogic.droppingBalls[i].x - 1) * 32, (12 - puyoLogic.droppingBalls[i].y) * 32, null);
i++;
} while(true);
for(int i = 1; i < 7; i++)
for(int j = 1; j < 13; j++)
PuyoLogic _tmp1 = puyoLogic;
if(puyoLogic.accumBalls[i][j] != 0)
g.drawImage(puyoImages[color2ImageIndex(puyoLogic.accumBalls[i][j])], (i - 1) * 32, (12 - j) * 32, null);
private void updateScore()
if(puyoLogic != null)
String s = (new StringBuilder()).append("Score: ").append(puyoLogic.score).toString();
labelScore.setText(s);
private void beginPuyo()
if(puyoLogic == null || !puyoLogic.running)
puyoLogic = new PuyoLogic(this);
(new Thread(puyoLogic)).start();
public static void main(String args[])
PuyoWindow puyoWin = new PuyoWindow();
i know he has mixed Swing with AWT now what i want to know is that what wrong do i do that i do not get my images drawn & the above code gets the images drawn