Ich arbeite an einer Hausaufgabe, in der ich ein Programm erstellen soll, mit dem Sie benutzerdefinierte Formen und Linien malen und auf dem Bildschirm verschieben können.

Ursprünglich war ich mit öffentlichen voidpaint(g) zu malen, aber die Formen flackerten, als ich repaint rief.

Damit ich auf @ umgestiegen bpaintComponent(g). Wenn ich jedoch versuche, eine Form zu malen, wird nichts angezeigt. Ich glaube, das liegt daran, dass es nicht auf dem @ malJPanel.

Der Rahmen hat 3 Felder in einer 3-reihigenBorderLayout.

[Button JPanel]
[Draw Box JPanel]
[Coordinate Jpanel]

Das Panel, auf das ich zeichnen möchte, ist natürlich das Draw Box-Panel.

Hier ist der Code, den ich derzeit habe:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuBar;
import javax.swing.JPanel;

public class Main extends JPanel implements ActionListener, MouseListener, MouseMotionListener {

private String colors[] = { "Black", "Red", "Orange", "Yellow", "Green", "Blue" };
private String shapes[] = { "Ellipse", "Line", "Rectangle" };
private JMenuBar toolBar; // flow layout? OR box layout x-Axis
private JPanel drawBox;
private JPanel coordBox;
private JLabel coords;
private JButton undo = new JButton("Undo");
private JButton clear = new JButton("Clear");
private JComboBox color = new JComboBox(colors);
private JComboBox shape = new JComboBox(shapes);
private JCheckBox fill = new JCheckBox("Filled");

public Main() {
JFrame frame = new JFrame("Paint");
frame.setSize(400, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setLayout(new BorderLayout());

/*
 * SETUP TOOLBAR
 */
toolBar = new JMenuBar();
toolBar.setLayout(new GridLayout(1, 5));
toolBar.add(undo);
toolBar.add(clear);
toolBar.add(color);
toolBar.add(shape);
toolBar.add(fill);

/*
 * ADD ACTION LISTENERS TO BUTTONS
 */
undo.addActionListener(this);
clear.addActionListener(this);
color.addActionListener(this);
shape.addActionListener(this);
fill.addActionListener(this);

/*
 * SETUP DRAW BOX
 */
drawBox = new JPanel();
drawBox.setOpaque(true);
drawBox.setPreferredSize(new Dimension(600, 400));
drawBox.addMouseListener(this);
drawBox.addMouseMotionListener(this);

/*
 * SETUP COORDINATES
 */
coords = new JLabel();
coordBox = new JPanel();

coordBox.setBackground(new Color(211, 211, 211));
coordBox.setPreferredSize(new Dimension(drawBox.getWidth(), 25));

coords.setText("Coords: [0,0]");
coords.addMouseMotionListener(this);

coordBox.add(coords);

/*
 * ADD TO FRAME
 */

frame.add(toolBar, BorderLayout.NORTH);
frame.add(drawBox, BorderLayout.CENTER);
frame.add(coordBox, BorderLayout.SOUTH);

frame.pack();

}

public static void main(String[] args) {
Main m = new Main();
}

public void paintComponent(Graphics g) {
// super.paintComponent(g);
g.setColor(Color.BLACK);
g.fillRect(300, 300, 100, 100);

}

@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == undo) {
    System.out.println("Undo Last");
}

if (e.getSource() == clear) {
    System.out.println("clearing screen");
}
// COLOR DROP DOWN BOX
if (e.getSource() == color) {
    JComboBox cb = (JComboBox) e.getSource();
    String selected = (String) cb.getSelectedItem();
    switch (selected) {

    case "Red":
    System.out.println("switching to color red");
    //ellipse.setColor(Color.RED);

    break;

    case "Orange":
    System.out.println("switch to coor orange");
    //ellipse.setColor(Color.ORANGE);
    break;
    case "Yellow":
    System.out.println("switching to color yellow");
    break;
    case "Green":
    System.out.println("Switching to green");
    //ellipse.setColor(Color.GREEN);

    break;
    case "Blue":
    System.out.println("Switching to blue");
    break;
    default:
    System.out.println("NOthing selected");
    break;
    }
}
// SHAPE DROP DOWN BOX
if (e.getSource() == shape) {
    JComboBox cb = (JComboBox) e.getSource();
    String selected = (String) cb.getSelectedItem();
    switch (selected) {
    case "Ellipse":
    System.out.println("switching to ellipse");
    break;
    case "Line":
    System.out.println("switch to line");
    break;
    case "Rectangle":
    System.out.println("switching to rectangle");
    break;

    default:
    System.out.println("NOthing selected");
    break;
    }
}

if (e.getSource() == fill) {
    JCheckBox cb = (JCheckBox) e.getSource();
    if (cb.isSelected()) {
    System.out.println("Fill shape");
    //ellipse.setFilled(true);
    } else {
    System.out.println("Empty shape");
    //ellipse.setFilled(false);
    }
}

}

@Override
public void mouseClicked(MouseEvent arg0) {
// System.out.println("Mouse clicked");

}

@Override
public void mouseEntered(MouseEvent e) {
System.out.println("Mouse entered");
}

@Override
public void mouseExited(MouseEvent arg0) {
coords.setText("Coords: N/A");

}

@Override
public void mousePressed(MouseEvent arg0) {
System.out.println("Mouse pressed");

}

@Override
public void mouseReleased(MouseEvent arg0) {
System.out.println("Mouse Released");

}

@Override
public void mouseDragged(MouseEvent e) {
coords.setText("Coords: [" + e.getX() + "," + e.getY() + "]");
}

@Override
public void mouseMoved(MouseEvent e) {
coords.setText("Coords: [" + e.getX() + "," + e.getY() + "]");
// repaint();
// revalidate();

}
}