我想在一张图片上画一个矩形框 矩形框写好了 继承了Jpanel 但是只要add到frame上 就会覆盖原来的内容
有什么办法不覆盖吗？ 两者都保留
下面代码main函数里 先add一个videoArea 然后再add矩形框的时候 就会覆盖原来的 有什么办法不覆盖吗 求教
```import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.*;
import java.awt.event.*;
public class DrawSketch extends JPanel implements MouseMotionListener {
private static final int recW = 75;
private static final int MAX = 1;
private Rectangle[] rect = new Rectangle[MAX];
private int numOfRecs = 0;
private int currentSquareIndex = -1;
public DrawSketch() {
addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent evt) {
int x = evt.getX();
int y = evt.getY();
currentSquareIndex = getRec(x, y);
if (currentSquareIndex < 0) // not inside a square
{
add(x, y);
}
}
// @Override
//
// public void mouseClicked(MouseEvent evt) {
//
// int x = evt.getX();
//
// int y = evt.getY();
//
// if (evt.getClickCount() >= 2) {
//
// remove(currentSquareIndex);
//
// }
//
// }
//
});
addMouseMotionListener(this);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
for (int i = 0; i < numOfRecs; i++) {
((Graphics2D) g).draw(rect[i]);
}
}
public int getRec(int x, int y) {
for (int i = 0; i < numOfRecs; i++) {
if (rect[i].contains(x, y)) {
return i;
}
}
return -1;
}
public void add(int x, int y) {
if (numOfRecs < MAX) {
rect[numOfRecs] = new Rectangle(x, y, recW, recW);
currentSquareIndex = numOfRecs;
numOfRecs++;
repaint();
}
}
@Override
public void remove(int n) {
if (n < 0 || n >= numOfRecs) {
return;
}
numOfRecs--;
rect[n] = rect[numOfRecs];
if (currentSquareIndex == n) {
currentSquareIndex = -1;
}
repaint();
}
@Override
public void mouseMoved(MouseEvent event) {
int x = event.getX();
int y = event.getY();
if (getRec(x, y) >= 0) {
setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
} else {
setCursor(Cursor.getDefaultCursor());
}
}
@Override
public void mouseDragged(MouseEvent event) {
int x = event.getX();
int y = event.getY();
System.out.println(x+"---"+y);
if (currentSquareIndex >= 0) {
Graphics graphics = getGraphics();
graphics.setXORMode(getBackground());
graphics.setColor(Color.RED);
((Graphics2D) graphics).draw(rect[currentSquareIndex]);
rect[currentSquareIndex].x = x;
rect[currentSquareIndex].y = y;
((Graphics2D) graphics).draw(rect[currentSquareIndex]);
graphics.dispose();
}
}
public static void main(String[] args) {
JFrame jFrame = new JFrame();
jFrame.setTitle("");
jFrame.setSize(1000, 500);
jFrame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
JLabel videoArea = new JLabel("load a video,please",JLabel.CENTER);
videoArea.setFont(new Font("",Font.BOLD,40));
videoArea.setBounds(new Rectangle(0, 0, 856, 480));
videoArea.setBorder(new EmptyBorder(0, 0, 0, 0));
Container cPane = jFrame.getContentPane();
cPane.add(videoArea);
cPane.add(new DrawSketch());
jFrame.setVisible(true);
}
}
