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私は、あなたがカスタムの形や線をペイントして画面の周りを動かすことができるプログラムを作ることになっている宿題に取り組んでいます。PaintComponentがJPanelにペイントされない[宿題]
元々私は塗装に公的な塗料（g）を使用していましたが、再塗装をしたときに形状がちらついていました。
そのため、私はpaintComponent（g）に切り替えました。しかし、私が形を描こうとすると何も現れません。これは私のJpanelの上に絵を描いていないからだと思う。
myフレームの3行のborderLayoutに3つのJpanelがあります。
[ボタンのJPanel]
[ボックスのJPanelを描画]
[JPanelの座標]
私が描きたいパネルが自然にボックスJPanelのドローです。しかしあなたの代わりに、GUIにメインのインスタンスを追加することはありません - ここ
は、私は現在、
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();
}
}
ありがとうございました。私はdrawBox JPanelを一括して取り除き、代わりにフレームに 'this'を追加しました。 – GreenFerret95