我正在尝试绘制以随机位置为中心的实心圆圈，并用一条线连接圆圈。到中心之间的距离显示在线条上，每当您调整框架大小时，圆圈都会重新显示在新的随机位置。我被困在如何显示距离？任何帮助表示赞赏，并提前感谢。这是代码（我设法做的）：
public class Test extends JFrame {
public Test() {
add(new LineConnectingTheTwoCircles());
}
// Panel class
class LineConnectingTheTwoCircles extends JPanel {
//Default constructor
LineConnectingTheTwoCircles() {
}
/* Override paintComponent (getting access to the panel's Graphics
class) */
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int radius = 15;
// getting coordinates of circle 1
int x1 = (int) (Math.random() * (getWidth()));
int y1 = (int) (Math.random() * (getHeight()));
// getting coordinates of circle 2
int x2 = (int) (Math.random() * (getWidth()));
int y2 = (int) (Math.random() * (getWidth()));
// Setting color and drawing a filled circles (1 & 2)
g.setColor(Color.BLUE);
g.fillOval(x1 - radius, y1 - radius, 2 * radius, 2 * radius);
g.drawString("1", x1 - 25, y1);
g.setColor(Color.RED);
g.fillOval(x2 - radius, y2 - radius, 2 * radius, 2 * radius);
g.drawString("2", x2 - 25, y2);
connectingTheTwoCircles(g, x1, y1, x2, y2);
}
// Connecting the two circles from the center
private void connectingTheTwoCircles(Graphics g, int x1, int y1,
int x2, int y2) {
//Distance between the circles centered
double D = Math.sqrt((Math.pow((y2 - y1), 2))
+ (Math.pow((x2 - x1), 2)));
//Getting the coordinates for the line l
int x11 = x1;
int y11 = y1;
int x21 = x2;
int y21 = y2;
g.setColor(Color.BLACK);
g.drawLine(x11, y11, x21, y21);
}
public double getDistance(double x1, double y1, double x2, double y2) {
return Math.sqrt((Math.pow((y2 - y1), 2))
+ (Math.pow((x2 - x1), 2)));
}
}
public static void main(String[] args) {
// Frame declaration
Test frame = new Test();
/*
* Invoking some methods, to set a title on the title bar, to specifier
* the size of the frame to centre it on the screen, to tell the program
* to terminate when the frame is closed and finally to display it
*/
frame.setTitle("This is a test");
frame.setSize(300, 300);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}